collections - osu.czhunka/vyuka/progobj/oop_8/java_8.pdf · 3 8.1 introduction • java collections...

1

CollectionsOutline

8.1 Introduction8.2 Collections Overview8.3 Class Arrays8.4 Interface Collection and Class Collections8.5 Lists8.6 Algorithms

8.6.1 Algorithm sort8.6.2 Algorithm shuffle8.6.3 Algorithms reverse, fill, copy, max and min8.6.4 Algorithm binarySearch

8.7 Sets8.8 Maps8.9 Synchronization Wrappers8.10 Unmodifiable Wrappers8.11 Abstract Implementations

2

CollectionsOutline

8.12 (Optional) Discovering Design Patterns: Design Patterns Used in Package java.util8.12.1 Creational Design Patterns8.12.2 Behavioral Design Patterns8.12.3 Conclusion

3

8.1 Introduction

• Java collections framework– Provides reusable componentry

– Common data structures• Example of code reuse

4

8.2 Collections Overview

• Collection– Data structure (object) that can hold references to other

objects

• Collections framework– Interfaces declare operations for various collection types

– Belong to package java.util• Collection

• Set

• List

• Map

5

8.3 Class ArraysArraysArraysArrays

• Class Arrays– Provides static methods for manipulating arrays

– Provides “high-level” methods• Method binarySearch for searching sorted arrays

• Method equals for comparing arrays

• Method fill for placing values into arrays

• Method sort for sorting arrays

Outline

UsingArrays.java

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12 // Using Java arrays.// Using Java arrays.// Using Java arrays.// Using Java arrays.

3 importimportimportimport java.util.*;java.util.*;java.util.*;java.util.*;

4 5 publicpublicpublicpublic classclassclassclass UsingArraysUsingArraysUsingArraysUsingArrays {{{{

6 privateprivateprivateprivate intintintint intValuesintValuesintValuesintValues[] = { [] = { [] = { [] = { 1111, , , , 2222, , , , 3333, , , , 4444, , , , 5555, , , , 6666 };};};};

7 privateprivateprivateprivate doubledoubledoubledouble doubleValuesdoubleValuesdoubleValuesdoubleValues[] = { [] = { [] = { [] = { 8.48.48.48.4, , , , 9.39.39.39.3, , , , 0.20.20.20.2, , , , 7.97.97.97.9, , , , 3.43.43.43.4 };};};};

8 privateprivateprivateprivate intintintint filledIntfilledIntfilledIntfilledInt[], [], [], [], intValuesCopyintValuesCopyintValuesCopyintValuesCopy[];[];[];[];

9 10 // initialize arrays// initialize arrays// initialize arrays// initialize arrays

11 publicpublicpublicpublic UsingArraysUsingArraysUsingArraysUsingArrays()()()()

12 {{{{

13 filledIntfilledIntfilledIntfilledInt = = = = newnewnewnew intintintint[ [ [ [ 10101010 ];];];];

14 intValuesCopyintValuesCopyintValuesCopyintValuesCopy = = = = newnewnewnew intintintint[ [ [ [ intValues.lengthintValues.lengthintValues.lengthintValues.length ];];];];

15 16 Arrays.fill( Arrays.fill( Arrays.fill( Arrays.fill( filledIntfilledIntfilledIntfilledInt, , , , 7777 ); ); ); ); // fill with 7s// fill with 7s// fill with 7s// fill with 7s

17 18 Arrays.sort( Arrays.sort( Arrays.sort( Arrays.sort( doubleValuesdoubleValuesdoubleValuesdoubleValues ); ); ); ); // sort // sort // sort // sort doubleValuesdoubleValuesdoubleValuesdoubleValues ascendingascendingascendingascending

19 20 // copy array // copy array // copy array // copy array intValuesintValuesintValuesintValues into array into array into array into array intValuesCopyintValuesCopyintValuesCopyintValuesCopy

21 System.arraycopySystem.arraycopySystem.arraycopySystem.arraycopy( ( ( ( intValuesintValuesintValuesintValues, , , , 0000, , , , intValuesCopyintValuesCopyintValuesCopyintValuesCopy, , , ,

22 0000, , , , intValues.lengthintValues.lengthintValues.lengthintValues.length ); ); ); );

23 }}}}

24

Outline

UsingArrays.java

25 // output values in each array// output values in each array// output values in each array// output values in each array

26 publicpublicpublicpublic voidvoidvoidvoid printArraysprintArraysprintArraysprintArrays()()()()

27 { { { {

28 System.out.print( System.out.print( System.out.print( System.out.print( """"doubleValuesdoubleValuesdoubleValuesdoubleValues: ": ": ": " ););););

29 30 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < ; count < ; count < ; count < doubleValues.lengthdoubleValues.lengthdoubleValues.lengthdoubleValues.length; count++ ); count++ ); count++ ); count++ )

31 System.out.print( System.out.print( System.out.print( System.out.print( doubleValuesdoubleValuesdoubleValuesdoubleValues[ count ] + [ count ] + [ count ] + [ count ] + " "" "" "" " ););););

32 33 System.out.print( System.out.print( System.out.print( System.out.print( """"\\\\nintValuesnintValuesnintValuesnintValues: ": ": ": " ););););

34 35 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < ; count < ; count < ; count < intValues.lengthintValues.lengthintValues.lengthintValues.length; count++ ); count++ ); count++ ); count++ )

36 System.out.print( System.out.print( System.out.print( System.out.print( intValuesintValuesintValuesintValues[ count ] + [ count ] + [ count ] + [ count ] + " "" "" "" " ););););

37 38 System.out.print( System.out.print( System.out.print( System.out.print( """"\\\\nfilledIntnfilledIntnfilledIntnfilledInt: ": ": ": " ););););

39 40 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < ; count < ; count < ; count < filledInt.lengthfilledInt.lengthfilledInt.lengthfilledInt.length; count++ ); count++ ); count++ ); count++ )

41 System.out.print( System.out.print( System.out.print( System.out.print( filledIntfilledIntfilledIntfilledInt[ count ] + [ count ] + [ count ] + [ count ] + " "" "" "" " ););););

42 43 System.out.print( System.out.print( System.out.print( System.out.print( """"\\\\nintValuesCopynintValuesCopynintValuesCopynintValuesCopy: ": ": ": " ););););

44 45 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < ; count < ; count < ; count < intValuesCopy.lengthintValuesCopy.lengthintValuesCopy.lengthintValuesCopy.length; count++ ); count++ ); count++ ); count++ )

46 System.out.print( System.out.print( System.out.print( System.out.print( intValuesCopyintValuesCopyintValuesCopyintValuesCopy[ count ] + [ count ] + [ count ] + [ count ] + " "" "" "" " ););););

47 48 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println();();();();

49 50 } } } } // end method // end method // end method // end method printArraysprintArraysprintArraysprintArrays

51

Outline

UsingArrays.java

Line 55

Lines 61 and 66

52 // find value in array // find value in array // find value in array // find value in array intValuesintValuesintValuesintValues

53 publicpublicpublicpublic intintintint searchForIntsearchForIntsearchForIntsearchForInt( ( ( ( intintintint value )value )value )value )

54 { { { {

55 returnreturnreturnreturn Arrays.binarySearchArrays.binarySearchArrays.binarySearchArrays.binarySearch( ( ( ( intValuesintValuesintValuesintValues, value );, value );, value );, value );

56 }}}}

57 58 // compare array contents// compare array contents// compare array contents// compare array contents

59 publicpublicpublicpublic voidvoidvoidvoid printEqualityprintEqualityprintEqualityprintEquality()()()()

60 {{{{

61 booleanbooleanbooleanboolean b = Arrays.equals( b = Arrays.equals( b = Arrays.equals( b = Arrays.equals( intValuesintValuesintValuesintValues, , , , intValuesCopyintValuesCopyintValuesCopyintValuesCopy ););););

62 63 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"intValuesintValuesintValuesintValues """" + ( b ? + ( b ? + ( b ? + ( b ? "==""==""==""==" : : : : "!=""!=""!=""!=" ) +) +) +) +

64 " " " " intValuesCopyintValuesCopyintValuesCopyintValuesCopy"""" ););););

65 66 b = Arrays.equals( b = Arrays.equals( b = Arrays.equals( b = Arrays.equals( intValuesintValuesintValuesintValues, , , , filledIntfilledIntfilledIntfilledInt ););););

67 68 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"intValuesintValuesintValuesintValues """" + ( b ? + ( b ? + ( b ? + ( b ? "==""==""==""==" : : : : "!=""!=""!=""!=" ) +) +) +) +

69 " " " " filledIntfilledIntfilledIntfilledInt"""" ););););

70 }}}}

71

Outline

UsingArrays.java

72 publicpublicpublicpublic staticstaticstaticstatic voidvoidvoidvoid main( String main( String main( String main( String argsargsargsargs[] )[] )[] )[] )

73 {{{{

74 UsingArraysUsingArraysUsingArraysUsingArrays usingArraysusingArraysusingArraysusingArrays = = = = newnewnewnew UsingArraysUsingArraysUsingArraysUsingArrays();();();();

75 76 usingArrays.printArraysusingArrays.printArraysusingArrays.printArraysusingArrays.printArrays();();();();

77 usingArrays.printEqualityusingArrays.printEqualityusingArrays.printEqualityusingArrays.printEquality();();();();

78 79 intintintint location = location = location = location = usingArrays.searchForIntusingArrays.searchForIntusingArrays.searchForIntusingArrays.searchForInt( ( ( ( 5555 ););););

80 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( location >= ( ( location >= ( ( location >= ( ( location >= 0000 ? ? ? ? "Found 5 at element ""Found 5 at element ""Found 5 at element ""Found 5 at element " + + + +

81 location : location : location : location : "5 not found""5 not found""5 not found""5 not found" ) + ) + ) + ) + " in " in " in " in intValuesintValuesintValuesintValues"""" ););););

82 83 location = location = location = location = usingArrays.searchForIntusingArrays.searchForIntusingArrays.searchForIntusingArrays.searchForInt( ( ( ( 8763876387638763 ););););

84 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( location >= ( ( location >= ( ( location >= ( ( location >= 0000 ? ? ? ? "Found 8763 at element ""Found 8763 at element ""Found 8763 at element ""Found 8763 at element " + + + +

85 location : location : location : location : "8763 not found""8763 not found""8763 not found""8763 not found" ) + ) + ) + ) + " in " in " in " in intValuesintValuesintValuesintValues"""" ); ); ); );

86 } } } }

87 88 } } } } // end class // end class // end class // end class UsingArraysUsingArraysUsingArraysUsingArrays

doubleValuesdoubleValuesdoubleValuesdoubleValues: 0.2 3.4 7.9 8.4 9.3: 0.2 3.4 7.9 8.4 9.3: 0.2 3.4 7.9 8.4 9.3: 0.2 3.4 7.9 8.4 9.3intValuesintValuesintValuesintValues: 1 2 3 4 5 6: 1 2 3 4 5 6: 1 2 3 4 5 6: 1 2 3 4 5 6filledIntfilledIntfilledIntfilledInt: 7 7 7 7 7 7 7 7 7 7: 7 7 7 7 7 7 7 7 7 7: 7 7 7 7 7 7 7 7 7 7: 7 7 7 7 7 7 7 7 7 7intValuesCopyintValuesCopyintValuesCopyintValuesCopy: 1 2 3 4 5 6: 1 2 3 4 5 6: 1 2 3 4 5 6: 1 2 3 4 5 6intValuesintValuesintValuesintValues == == == == intValuesCopyintValuesCopyintValuesCopyintValuesCopyintValuesintValuesintValuesintValues != != != != filledIntfilledIntfilledIntfilledIntFound 5 at element 4 in Found 5 at element 4 in Found 5 at element 4 in Found 5 at element 4 in intValuesintValuesintValuesintValues8763 not found in 8763 not found in 8763 not found in 8763 not found in intValuesintValuesintValuesintValues

Outline

UsingAsList.java

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12 // Using method // Using method // Using method // Using method asListasListasListasList....


4 5 publicpublicpublicpublic classclassclassclass UsingAsListUsingAsListUsingAsListUsingAsList {{{{

6 privateprivateprivateprivate staticstaticstaticstatic finalfinalfinalfinal String values[] = { String values[] = { String values[] = { String values[] = { "red""red""red""red", , , , "white""white""white""white", , , , "blue""blue""blue""blue" };};};};

7 privateprivateprivateprivate List list;List list;List list;List list;

8 9 // initialize List and set value at location 1// initialize List and set value at location 1// initialize List and set value at location 1// initialize List and set value at location 1

10 publicpublicpublicpublic UsingAsListUsingAsListUsingAsListUsingAsList()()()()

11 {{{{

12 list = list = list = list = Arrays.asListArrays.asListArrays.asListArrays.asList( values ); ( values ); ( values ); ( values ); // get List // get List // get List // get List

13 list.set( list.set( list.set( list.set( 1111, , , , "green""green""green""green" ); ); ); ); // change a value// change a value// change a value// change a value

14 }}}}

15 16 // output List and array// output List and array// output List and array// output List and array

17 publicpublicpublicpublic voidvoidvoidvoid printElementsprintElementsprintElementsprintElements()()()()

18 {{{{

19 System.out.print( System.out.print( System.out.print( System.out.print( "List elements : ""List elements : ""List elements : ""List elements : " ););););

20 21 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < list.size(); count++ ); count < list.size(); count++ ); count < list.size(); count++ ); count < list.size(); count++ )

22 System.out.print( list.get( count ) + System.out.print( list.get( count ) + System.out.print( list.get( count ) + System.out.print( list.get( count ) + " "" "" "" " ););););

23 24 System.out.print( System.out.print( System.out.print( System.out.print( """"\\\\nArraynArraynArraynArray elements: "elements: "elements: "elements: " ););););

25

Outline

UsingAsList.java

26 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < values.length; count++ ); count < values.length; count++ ); count < values.length; count++ ); count < values.length; count++ )

27 System.out.print( values[ count ] + System.out.print( values[ count ] + System.out.print( values[ count ] + System.out.print( values[ count ] + " "" "" "" " ););););


30 }}}}

31 32 publicpublicpublicpublic staticstaticstaticstatic voidvoidvoidvoid main( String main( String main( String main( String argsargsargsargs[] )[] )[] )[] )

33 {{{{

34 newnewnewnew UsingAsList().printElementsUsingAsList().printElementsUsingAsList().printElementsUsingAsList().printElements();();();();

35 } } } }

36 37 } } } } // end class // end class // end class // end class UsingAsListUsingAsListUsingAsListUsingAsList

List elements : red green blueList elements : red green blueList elements : red green blueList elements : red green blueArray elements: red green blueArray elements: red green blueArray elements: red green blueArray elements: red green blue

128.4 Interface CollectionCollectionCollectionCollection and ClassCollectionsCollectionsCollectionsCollections

• Interface Collection– Contains bulk operations

• Adding, clearing, comparing and retaining objects

– Interfaces Set and List extend interface Collection

• Class Collections– Provides static methods that manipulate collections

– Collections can be manipulated polymorphically

13

8.5 Lists

• List– Ordered Collection that can contain duplicate elements

– Sometimes called a sequence

– Implemented via interface List

• ArrayList

• LinkedList

• Vector

Outline

CollectionTest.java

Lines 15-20

Line 26

12 // Using the Collection interface.// Using the Collection interface.// Using the Collection interface.// Using the Collection interface.

3 importimportimportimport java.awt.Colorjava.awt.Colorjava.awt.Colorjava.awt.Color;;;;


5 6 publicpublicpublicpublic classclassclassclass CollectionTestCollectionTestCollectionTestCollectionTest {{{{

7 privateprivateprivateprivate staticstaticstaticstatic finalfinalfinalfinal String colors[] = { String colors[] = { String colors[] = { String colors[] = { "red""red""red""red", , , , "white""white""white""white", , , , "blue""blue""blue""blue" };};};};

8 9 // create // create // create // create ArrayListArrayListArrayListArrayList, add objects to it and manipulate it, add objects to it and manipulate it, add objects to it and manipulate it, add objects to it and manipulate it

10 publicpublicpublicpublic CollectionTestCollectionTestCollectionTestCollectionTest()()()()

11 {{{{

12 List list = List list = List list = List list = newnewnewnew ArrayListArrayListArrayListArrayList(); (); (); ();

13 14 // add objects to list// add objects to list// add objects to list// add objects to list

15 list.add( list.add( list.add( list.add( Color.MAGENTAColor.MAGENTAColor.MAGENTAColor.MAGENTA ); ); ); ); // add a color object// add a color object// add a color object// add a color object

16 17 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < colors.length; count++ ); count < colors.length; count++ ); count < colors.length; count++ ); count < colors.length; count++ )

18 list.add( colors[ count ] ); list.add( colors[ count ] ); list.add( colors[ count ] ); list.add( colors[ count ] );

19 20 list.add( list.add( list.add( list.add( Color.CYANColor.CYANColor.CYANColor.CYAN ); ); ); ); // add a color object// add a color object// add a color object// add a color object

21 22 // output list contents// output list contents// output list contents// output list contents

23 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"\\\\nArrayListnArrayListnArrayListnArrayList: ": ": ": " ););););



27

Outline

CollectionTest.java

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28 28 28 28 // remove all String objects// remove all String objects// remove all String objects// remove all String objects

29 29 29 29 removeStringsremoveStringsremoveStringsremoveStrings( list );( list );( list );( list );

30 30 30 30

31 31 31 31 // output list contents// output list contents// output list contents// output list contents

32 32 32 32 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"\\\\nnnn\\\\nArrayListnArrayListnArrayListnArrayList after calling after calling after calling after calling removeStringsremoveStringsremoveStringsremoveStrings: ": ": ": "););););

33 33 33 33

34 34 34 34 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < list.size(); count++ ); count < list.size(); count++ ); count < list.size(); count++ ); count < list.size(); count++ )

35 35 35 35 System.out.print( list.get( count ) + System.out.print( list.get( count ) + System.out.print( list.get( count ) + System.out.print( list.get( count ) + " "" "" "" " ););););

36 36 36 36

37 37 37 37 } } } } // end constructor // end constructor // end constructor // end constructor CollectionTestCollectionTestCollectionTestCollectionTest

38 38 38 38

39 39 39 39 // remove String objects from Collection// remove String objects from Collection// remove String objects from Collection// remove String objects from Collection

40 40 40 40 privateprivateprivateprivate voidvoidvoidvoid removeStringsremoveStringsremoveStringsremoveStrings( Collection collection )( Collection collection )( Collection collection )( Collection collection )

41 41 41 41 {{{{

42 42 42 42 IteratorIteratorIteratorIterator iteratoriteratoriteratoriterator = = = = collection.iteratorcollection.iteratorcollection.iteratorcollection.iterator(); (); (); (); // get // get // get // get iteratoriteratoriteratoriterator

43 43 43 43

44 44 44 44 // loop while collection has items // loop while collection has items // loop while collection has items // loop while collection has items

45 45 45 45 whilewhilewhilewhile ( ( ( ( iterator.hasNextiterator.hasNextiterator.hasNextiterator.hasNext() ) () ) () ) () )

46 46 46 46

47 47 47 47 ifififif ( ( ( ( iterator.nextiterator.nextiterator.nextiterator.next() () () () instanceofinstanceofinstanceofinstanceof String ) String ) String ) String )

48 48 48 48 iterator.removeiterator.removeiterator.removeiterator.remove(); (); (); (); // remove String object // remove String object // remove String object // remove String object

49 49 49 49 }}}}

50 50 50 50

Outline

CollectionTest.java

51 51 51 51 publicpublicpublicpublic staticstaticstaticstatic voidvoidvoidvoid main( String main( String main( String main( String argsargsargsargs[] )[] )[] )[] )

52 52 52 52 {{{{

53 53 53 53 newnewnewnew CollectionTestCollectionTestCollectionTestCollectionTest();();();();

54 54 54 54 } } } }

55 55 55 55

56 56 56 56 } } } } // end class // end class // end class // end class CollectionTestCollectionTestCollectionTestCollectionTest

ArrayListArrayListArrayListArrayList::::java.awt.Color[rjava.awt.Color[rjava.awt.Color[rjava.awt.Color[r=255,g=0,b=255] red white blue =255,g=0,b=255] red white blue =255,g=0,b=255] red white blue =255,g=0,b=255] red white blue java.awt.Colorjava.awt.Colorjava.awt.Colorjava.awt.Color[r=0,g=255,b=255][r=0,g=255,b=255][r=0,g=255,b=255][r=0,g=255,b=255]

ArrayListArrayListArrayListArrayList after calling after calling after calling after calling removeStringsremoveStringsremoveStringsremoveStrings::::java.awt.Color[rjava.awt.Color[rjava.awt.Color[rjava.awt.Color[r=255,g=0,b=255] =255,g=0,b=255] =255,g=0,b=255] =255,g=0,b=255] java.awt.Color[rjava.awt.Color[rjava.awt.Color[rjava.awt.Color[r=0,g=255,b=255]=0,g=255,b=255]=0,g=255,b=255]=0,g=255,b=255]

Outline

ListTest.java

Lines 14-15

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12 // Using // Using // Using // Using LinkListsLinkListsLinkListsLinkLists....


4 5 publicpublicpublicpublic classclassclassclass ListTestListTestListTestListTest {{{{

6 privateprivateprivateprivate staticstaticstaticstatic finalfinalfinalfinal String colors[] = { String colors[] = { String colors[] = { String colors[] = { "black""black""black""black", , , , "yellow""yellow""yellow""yellow", , , ,

7 "green""green""green""green", , , , "blue""blue""blue""blue", , , , "violet""violet""violet""violet", , , , "silver""silver""silver""silver" };};};};

8 privateprivateprivateprivate staticstaticstaticstatic finalfinalfinalfinal String colors2[] = { String colors2[] = { String colors2[] = { String colors2[] = { "gold""gold""gold""gold", , , , "white""white""white""white", , , ,

9 "brown""brown""brown""brown", , , , "blue""blue""blue""blue", , , , "gray""gray""gray""gray", , , , "silver""silver""silver""silver" };};};};

10 11 // set up and manipulate // set up and manipulate // set up and manipulate // set up and manipulate LinkedListLinkedListLinkedListLinkedList objectsobjectsobjectsobjects

12 publicpublicpublicpublic ListTestListTestListTestListTest()()()()

13 {{{{

14 List link = List link = List link = List link = newnewnewnew LinkedListLinkedListLinkedListLinkedList(); (); (); ();

15 List link2 = List link2 = List link2 = List link2 = newnewnewnew LinkedListLinkedListLinkedListLinkedList();();();();

16 17 // add elements to each list// add elements to each list// add elements to each list// add elements to each list

18 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < colors.length; count++ ) {; count < colors.length; count++ ) {; count < colors.length; count++ ) {; count < colors.length; count++ ) {

19 link.add( colors[ count ] ); link.add( colors[ count ] ); link.add( colors[ count ] ); link.add( colors[ count ] );

20 link2.add( colors2[ count ] );link2.add( colors2[ count ] );link2.add( colors2[ count ] );link2.add( colors2[ count ] );

21 }}}}

22 23 link.addAlllink.addAlllink.addAlllink.addAll( link2 ); ( link2 ); ( link2 ); ( link2 ); // concatenate lists// concatenate lists// concatenate lists// concatenate lists

24 link2 = link2 = link2 = link2 = nullnullnullnull; ; ; ; // release resources// release resources// release resources// release resources

25

Outline

ListTest.java

Lines 42-50

26 printListprintListprintListprintList( link );( link );( link );( link );

27 28 uppercaseStringsuppercaseStringsuppercaseStringsuppercaseStrings( link );( link );( link );( link );

29 30 printListprintListprintListprintList( link );( link );( link );( link );

31 32 System.out.print( System.out.print( System.out.print( System.out.print( """"\\\\nDeletingnDeletingnDeletingnDeleting elements 4 to 6..."elements 4 to 6..."elements 4 to 6..."elements 4 to 6..." ););););

33 removeItemsremoveItemsremoveItemsremoveItems( link, ( link, ( link, ( link, 4444, , , , 7777 ););););

34 35 printListprintListprintListprintList( link );( link );( link );( link );

36 37 printReversedListprintReversedListprintReversedListprintReversedList( link );( link );( link );( link );

38 39 } } } } // end constructor // end constructor // end constructor // end constructor ListTestListTestListTestListTest

40 41 // output List contents// output List contents// output List contents// output List contents

42 publicpublicpublicpublic voidvoidvoidvoid printListprintListprintListprintList( List list )( List list )( List list )( List list )

43 {{{{

44 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"\\\\nlistnlistnlistnlist: ": ": ": " ););););




50 } } } }

Outline

ListTest.java

Lines 53-63

Line 68

51 52 // locate String objects and convert to uppercase// locate String objects and convert to uppercase// locate String objects and convert to uppercase// locate String objects and convert to uppercase

53 privateprivateprivateprivate voidvoidvoidvoid uppercaseStringsuppercaseStringsuppercaseStringsuppercaseStrings( List list )( List list )( List list )( List list )

54 {{{{

55 ListIteratorListIteratorListIteratorListIterator iteratoriteratoriteratoriterator = = = = list.listIteratorlist.listIteratorlist.listIteratorlist.listIterator();();();();

56 57 whilewhilewhilewhile ( ( ( ( iterator.hasNextiterator.hasNextiterator.hasNextiterator.hasNext() ) {() ) {() ) {() ) {

58 Object object = Object object = Object object = Object object = iterator.nextiterator.nextiterator.nextiterator.next(); (); (); (); // get item// get item// get item// get item

59 60 ifififif ( object ( object ( object ( object instanceofinstanceofinstanceofinstanceof String ) String ) String ) String ) // check for String// check for String// check for String// check for String

61 iterator.setiterator.setiterator.setiterator.set( ( ( String ) object ).( ( ( String ) object ).( ( ( String ) object ).( ( ( String ) object ).toUpperCasetoUpperCasetoUpperCasetoUpperCase() ); () ); () ); () );

62 }}}}

63 }}}}

64 65 // obtain // obtain // obtain // obtain sublistsublistsublistsublist and use clear method to delete and use clear method to delete and use clear method to delete and use clear method to delete sublistsublistsublistsublist itemsitemsitemsitems

66 privateprivateprivateprivate voidvoidvoidvoid removeItemsremoveItemsremoveItemsremoveItems( List list, ( List list, ( List list, ( List list, intintintint start, start, start, start, intintintint end )end )end )end )

67 {{{{

68 list.subListlist.subListlist.subListlist.subList( start, end ).clear(); ( start, end ).clear(); ( start, end ).clear(); ( start, end ).clear(); // remove items// remove items// remove items// remove items

69 }}}}

70 71 // print reversed list// print reversed list// print reversed list// print reversed list

72 privateprivateprivateprivate voidvoidvoidvoid printReversedListprintReversedListprintReversedListprintReversedList( List list )( List list )( List list )( List list )

73 {{{{

74 ListIteratorListIteratorListIteratorListIterator iteratoriteratoriteratoriterator = = = = list.listIteratorlist.listIteratorlist.listIteratorlist.listIterator( list.size() );( list.size() );( list.size() );( list.size() );

75

Outline

ListTest.java

Line 79

Line 80

76 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"\\\\nReversednReversednReversednReversed List:"List:"List:"List:" ););););

77 78 // print list in reverse order// print list in reverse order// print list in reverse order// print list in reverse order

79 whilewhilewhilewhile( ( ( ( iterator.hasPreviousiterator.hasPreviousiterator.hasPreviousiterator.hasPrevious() ) () ) () ) () )

80 System.out.print( System.out.print( System.out.print( System.out.print( iterator.previousiterator.previousiterator.previousiterator.previous() + () + () + () + " "" "" "" " ); ); ); );

81 }}}}


84 {{{{

85 newnewnewnew ListTestListTestListTestListTest();();();();

86 } } } }

87 88 } } } } // end class // end class // end class // end class ListTestListTestListTestListTest

list:list:list:list:black yellow green blue violet silver gold white brown blue grayblack yellow green blue violet silver gold white brown blue grayblack yellow green blue violet silver gold white brown blue grayblack yellow green blue violet silver gold white brown blue gray silversilversilversilver

list:list:list:list:BLACK YELLOW GREEN BLUE VIOLET SILVER GOLD WHITE BROWN BLUE GRAYBLACK YELLOW GREEN BLUE VIOLET SILVER GOLD WHITE BROWN BLUE GRAYBLACK YELLOW GREEN BLUE VIOLET SILVER GOLD WHITE BROWN BLUE GRAYBLACK YELLOW GREEN BLUE VIOLET SILVER GOLD WHITE BROWN BLUE GRAY SILVERSILVERSILVERSILVER

Deleting elements 4 to 6...Deleting elements 4 to 6...Deleting elements 4 to 6...Deleting elements 4 to 6...list:list:list:list:BLACK YELLOW GREEN BLUE WHITE BROWN BLUE GRAY SILVERBLACK YELLOW GREEN BLUE WHITE BROWN BLUE GRAY SILVERBLACK YELLOW GREEN BLUE WHITE BROWN BLUE GRAY SILVERBLACK YELLOW GREEN BLUE WHITE BROWN BLUE GRAY SILVER

Reversed List:Reversed List:Reversed List:Reversed List:SILVER GRAY BLUE BROWN WHITE BLUE GREEN YELLOW BLACK SILVER GRAY BLUE BROWN WHITE BLUE GREEN YELLOW BLACK SILVER GRAY BLUE BROWN WHITE BLUE GREEN YELLOW BLACK SILVER GRAY BLUE BROWN WHITE BLUE GREEN YELLOW BLACK

Outline

UsingToArray.java

Line 20

1 1 1 1 // Fig. 22.5: // Fig. 22.5: // Fig. 22.5: // Fig. 22.5: UsingToArray.javaUsingToArray.javaUsingToArray.javaUsingToArray.java

2 2 2 2 // Using method // Using method // Using method // Using method toArraytoArraytoArraytoArray....

3 3 3 3 importimportimportimport java.util.*;java.util.*;java.util.*;java.util.*;

4 4 4 4

5 5 5 5 publicpublicpublicpublic classclassclassclass UsingToArrayUsingToArrayUsingToArrayUsingToArray {{{{

6 6 6 6

7 7 7 7 // create // create // create // create LinkedListLinkedListLinkedListLinkedList, add elements and convert to array, add elements and convert to array, add elements and convert to array, add elements and convert to array

8 8 8 8 publicpublicpublicpublic UsingToArrayUsingToArrayUsingToArrayUsingToArray()()()()

9 9 9 9 {{{{

10 10 10 10 String colors[] = { String colors[] = { String colors[] = { String colors[] = { "black""black""black""black", , , , "blue""blue""blue""blue", , , , "yellow""yellow""yellow""yellow" };};};};

11 11 11 11

12 12 12 12 LinkedListLinkedListLinkedListLinkedList links = links = links = links = newnewnewnew LinkedListLinkedListLinkedListLinkedList( ( ( ( Arrays.asListArrays.asListArrays.asListArrays.asList( colors ) );( colors ) );( colors ) );( colors ) );

13 13 13 13

14 14 14 14 links.addLastlinks.addLastlinks.addLastlinks.addLast( ( ( ( "red""red""red""red" ); ); ); ); // add as last item // add as last item // add as last item // add as last item

15 15 15 15 links.add( links.add( links.add( links.add( "pink""pink""pink""pink" ); ); ); ); // add to the end // add to the end // add to the end // add to the end

16 16 16 16 links.add( links.add( links.add( links.add( 3333, , , , "green""green""green""green" ); ); ); ); // add at 3rd index // add at 3rd index // add at 3rd index // add at 3rd index

17 17 17 17 links.addFirstlinks.addFirstlinks.addFirstlinks.addFirst( ( ( ( "cyan""cyan""cyan""cyan" ); ); ); ); // add as first item // add as first item // add as first item // add as first item

18 18 18 18

19 19 19 19 // get // get // get // get LinkedListLinkedListLinkedListLinkedList elements as an array elements as an array elements as an array elements as an array

20 20 20 20 colors = ( String [] ) colors = ( String [] ) colors = ( String [] ) colors = ( String [] ) links.toArraylinks.toArraylinks.toArraylinks.toArray( ( ( ( newnewnewnew String[ links.size() ] );String[ links.size() ] );String[ links.size() ] );String[ links.size() ] );

21 21 21 21

22 22 22 22 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "colors: ""colors: ""colors: ""colors: " ););););

23 23 23 23

Outline

UsingToArray.java

24 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < colors.length; count++ ); count < colors.length; count++ ); count < colors.length; count++ ); count < colors.length; count++ )

25 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( colors[ count ] );( colors[ count ] );( colors[ count ] );( colors[ count ] );

26 }}}}


29 {{{{

30 newnewnewnew UsingToArrayUsingToArrayUsingToArrayUsingToArray();();();();

31 } } } }

32 33 } } } } // end class // end class // end class // end class UsingToArrayUsingToArrayUsingToArrayUsingToArray

colors:colors:colors:colors:cyancyancyancyanblackblackblackblackblueblueblueblueyellowyellowyellowyellowgreengreengreengreenredredredredpinkpinkpinkpink

23

8.6 Algorithms

• Collections Framework provides set of algorithms– Implemented as static methods

• List algorithms

– sort

– binarySearch

– reverse

– shuffle

– fill

– copy

• Collection algorithms

– min

– max

24

8.6.1 Algorithm sortsortsortsort

• sort– Sorts List elements

• Order is determined by natural order of elements’ type

• Relatively fast

Outline

Sort1.java

Line 13

Line 18

12 // Using algorithm sort.// Using algorithm sort.// Using algorithm sort.// Using algorithm sort.


4 5 publicpublicpublicpublic classclassclassclass Sort1 {Sort1 {Sort1 {Sort1 {

6 privateprivateprivateprivate staticstaticstaticstatic finalfinalfinalfinal String suits[] = String suits[] = String suits[] = String suits[] =

7 { { { { "Hearts""Hearts""Hearts""Hearts", , , , "Diamonds""Diamonds""Diamonds""Diamonds", , , , "Clubs""Clubs""Clubs""Clubs", , , , "Spades""Spades""Spades""Spades" };};};};

8 9 // display array elements// display array elements// display array elements// display array elements


11 {{{{

12 // create // create // create // create ArrayListArrayListArrayListArrayList

13 List list = List list = List list = List list = newnewnewnew ArrayListArrayListArrayListArrayList( ( ( ( Arrays.asListArrays.asListArrays.asListArrays.asList( suits ) );( suits ) );( suits ) );( suits ) );

14 15 // output list// output list// output list// output list

16 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "Unsorted array elements:"Unsorted array elements:"Unsorted array elements:"Unsorted array elements:\\\\n"n"n"n" + list );+ list );+ list );+ list );

17 18 Collections.sort( list ); Collections.sort( list ); Collections.sort( list ); Collections.sort( list ); // sort // sort // sort // sort ArrayListArrayListArrayListArrayList

19 20 // output list// output list// output list// output list

21 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "Sorted array elements:"Sorted array elements:"Sorted array elements:"Sorted array elements:\\\\n"n"n"n" + list );+ list );+ list );+ list );

22 }}}}

23

Outline

Sort1.java

Unsorted array elements:Unsorted array elements:Unsorted array elements:Unsorted array elements:

[Hearts, Diamonds, Clubs, Spades][Hearts, Diamonds, Clubs, Spades][Hearts, Diamonds, Clubs, Spades][Hearts, Diamonds, Clubs, Spades]

Sorted array elements:Sorted array elements:Sorted array elements:Sorted array elements:

[Clubs, Diamonds, Hearts, Spades][Clubs, Diamonds, Hearts, Spades][Clubs, Diamonds, Hearts, Spades][Clubs, Diamonds, Hearts, Spades]


25 {{{{

26 newnewnewnew Sort1().printElements();Sort1().printElements();Sort1().printElements();Sort1().printElements();

27 } } } }

28 29 } } } } // end class Sort1// end class Sort1// end class Sort1// end class Sort1

Outline

Sort2.java

Line 18

Line 18

12 // Using a Comparator object with algorithm sort.// Using a Comparator object with algorithm sort.// Using a Comparator object with algorithm sort.// Using a Comparator object with algorithm sort.




7 { { { { "Hearts""Hearts""Hearts""Hearts", , , , "Diamonds""Diamonds""Diamonds""Diamonds", , , , "Clubs""Clubs""Clubs""Clubs", , , , "Spades""Spades""Spades""Spades" };};};};

8 9 // output List elements// output List elements// output List elements// output List elements


11 {{{{

12 List list = List list = List list = List list = Arrays.asListArrays.asListArrays.asListArrays.asList( suits ); ( suits ); ( suits ); ( suits ); // create List// create List// create List// create List


15 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "Unsorted array elements:"Unsorted array elements:"Unsorted array elements:"Unsorted array elements:\\\\n"n"n"n" + list );+ list );+ list );+ list );

16 17 // sort in descending order using a comparator// sort in descending order using a comparator// sort in descending order using a comparator// sort in descending order using a comparator

18 Collections.sort( list, Collections.sort( list, Collections.sort( list, Collections.sort( list, Collections.reverseOrderCollections.reverseOrderCollections.reverseOrderCollections.reverseOrder() ); () ); () ); () );


21 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "Sorted list elements:"Sorted list elements:"Sorted list elements:"Sorted list elements:\\\\n"n"n"n" + list );+ list );+ list );+ list );

22 }}}}

23

Outline

Sort2.java


[Hearts, Diamonds, Clubs, Spades][Hearts, Diamonds, Clubs, Spades][Hearts, Diamonds, Clubs, Spades][Hearts, Diamonds, Clubs, Spades]

Sorted list elements:Sorted list elements:Sorted list elements:Sorted list elements:

[Spades, Hearts, Diamonds, Clubs][Spades, Hearts, Diamonds, Clubs][Spades, Hearts, Diamonds, Clubs][Spades, Hearts, Diamonds, Clubs]


25 {{{{


27 } } } }


Outline

Sort3.java

Line 21

12 // Creating a custom Comparator class.// Creating a custom Comparator class.// Creating a custom Comparator class.// Creating a custom Comparator class.



6 7 public voidpublic voidpublic voidpublic void printElementsprintElementsprintElementsprintElements()()()()

8 {{{{

9 List list = new List list = new List list = new List list = new ArrayListArrayListArrayListArrayList();();();(); // create List// create List// create List// create List

10 11 list.add( list.add( list.add( list.add( newnewnewnew Time2( Time2( Time2( Time2( 6666, , , , 24242424, , , , 34343434 ) );) );) );) );

12 list.add( list.add( list.add( list.add( newnewnewnew Time2( Time2( Time2( Time2( 18181818, , , , 14141414, , , , 05050505 ) );) );) );) );





18 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println(((( "Unsorted array elements:"Unsorted array elements:"Unsorted array elements:"Unsorted array elements:\\\\n"n"n"n" + list );+ list );+ list );+ list );

19 20 // sort in order using a comparator// sort in order using a comparator// sort in order using a comparator// sort in order using a comparator

21 Collections.sort( list, Collections.sort( list, Collections.sort( list, Collections.sort( list, newnewnewnew TimeComparatorTimeComparatorTimeComparatorTimeComparator() );() );() );() );


24 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "Sorted list elements:"Sorted list elements:"Sorted list elements:"Sorted list elements:\\\\n"n"n"n" + list );+ list );+ list );+ list );

25 }}}}

26

Outline

Sort3.java

Line 32

Line 36


28 {{{{


30 } } } }

31 32 privateprivateprivateprivate classclassclassclass TimeComparatorTimeComparatorTimeComparatorTimeComparator implementsimplementsimplementsimplements Comparator {Comparator {Comparator {Comparator {

33 intintintint hourComparehourComparehourComparehourCompare, , , , minuteCompareminuteCompareminuteCompareminuteCompare, , , , secondComparesecondComparesecondComparesecondCompare;;;;

34 Time2 time1, time2;Time2 time1, time2;Time2 time1, time2;Time2 time1, time2;

35 36 publicpublicpublicpublic intintintint compare(Object object1, Object object2)compare(Object object1, Object object2)compare(Object object1, Object object2)compare(Object object1, Object object2)

37 {{{{

38 // cast the objects// cast the objects// cast the objects// cast the objects

39 time1 = (Time2)object1;time1 = (Time2)object1;time1 = (Time2)object1;time1 = (Time2)object1;

40 time2 = (Time2)object2;time2 = (Time2)object2;time2 = (Time2)object2;time2 = (Time2)object2;

41 42 hourComparehourComparehourComparehourCompare = = = = newnewnewnew Integer( time1.getHour() ).Integer( time1.getHour() ).Integer( time1.getHour() ).Integer( time1.getHour() ).compareTocompareTocompareTocompareTo((((

43 newnewnewnew Integer( time2.getHour() ) );Integer( time2.getHour() ) );Integer( time2.getHour() ) );Integer( time2.getHour() ) );

44 45 // test the hour first// test the hour first// test the hour first// test the hour first

46 ifififif ( ( ( ( hourComparehourComparehourComparehourCompare != != != != 0000 ))))

47 returnreturnreturnreturn hourComparehourComparehourComparehourCompare;;;;

48 49 minuteCompareminuteCompareminuteCompareminuteCompare = = = = newnewnewnew Integer( time1.getMinute() ).Integer( time1.getMinute() ).Integer( time1.getMinute() ).Integer( time1.getMinute() ).compareTocompareTocompareTocompareTo((((

50 newnewnewnew Integer( time2.getMinute() ) );Integer( time2.getMinute() ) );Integer( time2.getMinute() ) );Integer( time2.getMinute() ) );

51

Outline

Sort3.java


[06:24:34, 18:14:05, 08:05:00, 12:07:58, 06:14:22][06:24:34, 18:14:05, 08:05:00, 12:07:58, 06:14:22][06:24:34, 18:14:05, 08:05:00, 12:07:58, 06:14:22][06:24:34, 18:14:05, 08:05:00, 12:07:58, 06:14:22]

Sorted list elements:Sorted list elements:Sorted list elements:Sorted list elements:

[06:14:22, 06:24:34, 08:05:00, 12:07:58, 18:14:05][06:14:22, 06:24:34, 08:05:00, 12:07:58, 18:14:05][06:14:22, 06:24:34, 08:05:00, 12:07:58, 18:14:05][06:14:22, 06:24:34, 08:05:00, 12:07:58, 18:14:05]

52 // then test the minute// then test the minute// then test the minute// then test the minute

53 ifififif ( ( ( ( minuteCompareminuteCompareminuteCompareminuteCompare != != != != 0000 ))))

54 returnreturnreturnreturn minuteCompareminuteCompareminuteCompareminuteCompare;;;;

55 56 secondComparesecondComparesecondComparesecondCompare = = = = newnewnewnew Integer( time1.getSecond() ).Integer( time1.getSecond() ).Integer( time1.getSecond() ).Integer( time1.getSecond() ).compareTocompareTocompareTocompareTo((((

57 newnewnewnew Integer( time2.getSecond() ) );Integer( time2.getSecond() ) );Integer( time2.getSecond() ) );Integer( time2.getSecond() ) );

58 59 returnreturnreturnreturn secondComparesecondComparesecondComparesecondCompare; ; ; ; // return result of comparing seconds// return result of comparing seconds// return result of comparing seconds// return result of comparing seconds

60 }}}}

61 62 } } } } // end class // end class // end class // end class TimeComparatorTimeComparatorTimeComparatorTimeComparator


32

8.6.2 Algorithm shuffle

• shuffle– Randomly orders List elements

Outline

Cards.java

1 Cards.javaCards.javaCards.javaCards.java

2 // Using algorithm shuffle.// Using algorithm shuffle.// Using algorithm shuffle.// Using algorithm shuffle.


4 5 // class to represent a Card in a deck of cards// class to represent a Card in a deck of cards// class to represent a Card in a deck of cards// class to represent a Card in a deck of cards

6 classclassclassclass Card {Card {Card {Card {

7 privateprivateprivateprivate String face;String face;String face;String face;

8 privateprivateprivateprivate String suit;String suit;String suit;String suit;

9 10 // initialize a Card// initialize a Card// initialize a Card// initialize a Card

11 publicpublicpublicpublic Card( String Card( String Card( String Card( String initialfaceinitialfaceinitialfaceinitialface, String , String , String , String initialSuitinitialSuitinitialSuitinitialSuit ))))

12 {{{{

13 face = face = face = face = initialfaceinitialfaceinitialfaceinitialface;;;;

14 suit = suit = suit = suit = initialSuitinitialSuitinitialSuitinitialSuit;;;;

15 }}}}

16 17 // return face of Card// return face of Card// return face of Card// return face of Card

18 publicpublicpublicpublic String String String String getFacegetFacegetFacegetFace() () () ()

19 { { { {

20 returnreturnreturnreturn face; face; face; face;

21 }}}}

22 23 // return suit of Card// return suit of Card// return suit of Card// return suit of Card

24 publicpublicpublicpublic String String String String getSuitgetSuitgetSuitgetSuit() () () ()

25 { { { {

26 returnreturnreturnreturn suit; suit; suit; suit;

27 }}}}

Outline

Cards.java

28 29 // return String representation of Card// return String representation of Card// return String representation of Card// return String representation of Card

30 publicpublicpublicpublic String String String String toStringtoStringtoStringtoString()()()()

31 {{{{

32 StringBufferStringBufferStringBufferStringBuffer buffer = buffer = buffer = buffer = newnewnewnew StringBufferStringBufferStringBufferStringBuffer( face + ( face + ( face + ( face + " of "" of "" of "" of " + suit );+ suit );+ suit );+ suit );

33 buffer.setLengthbuffer.setLengthbuffer.setLengthbuffer.setLength( ( ( ( 20202020 ););););

34 35 returnreturnreturnreturn buffer.toStringbuffer.toStringbuffer.toStringbuffer.toString();();();();

36 }}}}

37 38 } } } } // end class Card// end class Card// end class Card// end class Card

39 40 // class Cards declaration// class Cards declaration// class Cards declaration// class Cards declaration

41 publicpublicpublicpublic classclassclassclass Cards {Cards {Cards {Cards {


43 { { { { "Hearts""Hearts""Hearts""Hearts", , , , "Clubs""Clubs""Clubs""Clubs", , , , "Diamonds""Diamonds""Diamonds""Diamonds", , , , "Spades""Spades""Spades""Spades" };};};};

44 privateprivateprivateprivate staticstaticstaticstatic finalfinalfinalfinal String faces[] = { String faces[] = { String faces[] = { String faces[] = { "Ace""Ace""Ace""Ace", , , , "Deuce""Deuce""Deuce""Deuce", , , , "Three""Three""Three""Three",,,,

45 "Four""Four""Four""Four", , , , "Five""Five""Five""Five", , , , "Six""Six""Six""Six", , , , "Seven""Seven""Seven""Seven", , , , "Eight""Eight""Eight""Eight", , , , "Nine""Nine""Nine""Nine", , , , "Ten""Ten""Ten""Ten",,,,

46 "Jack""Jack""Jack""Jack", , , , "Queen""Queen""Queen""Queen", , , , "King""King""King""King" };};};};

47 privateprivateprivateprivate List list;List list;List list;List list;

48 49 // set up deck of Cards and shuffle// set up deck of Cards and shuffle// set up deck of Cards and shuffle// set up deck of Cards and shuffle

50 publicpublicpublicpublic Cards()Cards()Cards()Cards()

51 {{{{

52 Card deck[] = Card deck[] = Card deck[] = Card deck[] = newnewnewnew Card[ Card[ Card[ Card[ 52525252 ];];];];

53

Outline

Cards.java

Line 59

54 forforforfor ( ( ( ( intintintint count = count = count = count = 0000; count < deck.length; count++ ); count < deck.length; count++ ); count < deck.length; count++ ); count < deck.length; count++ )

55 deck[ count ] = deck[ count ] = deck[ count ] = deck[ count ] = newnewnewnew Card( faces[ count % Card( faces[ count % Card( faces[ count % Card( faces[ count % 13131313 ],],],],

56 suits[ count / suits[ count / suits[ count / suits[ count / 13131313 ] );] );] );] );

57 58 list = list = list = list = Arrays.asListArrays.asListArrays.asListArrays.asList( deck ); ( deck ); ( deck ); ( deck ); // get List // get List // get List // get List

59 Collections.shuffle( list ); Collections.shuffle( list ); Collections.shuffle( list ); Collections.shuffle( list ); // shuffle deck// shuffle deck// shuffle deck// shuffle deck

60 }}}}

61 62 // output deck// output deck// output deck// output deck

63 publicpublicpublicpublic voidvoidvoidvoid printCardsprintCardsprintCardsprintCards()()()()

64 {{{{

65 intintintint half = list.size() / half = list.size() / half = list.size() / half = list.size() / 2222 ---- 1111;;;;

66 67 forforforfor ( ( ( ( intintintint i = i = i = i = 0000, j = half + , j = half + , j = half + , j = half + 1111; i <= half; i++, j++ ); i <= half; i++, j++ ); i <= half; i++, j++ ); i <= half; i++, j++ )

68 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( list.get( i ).( list.get( i ).( list.get( i ).( list.get( i ).toStringtoStringtoStringtoString() + list.get( j ) );() + list.get( j ) );() + list.get( j ) );() + list.get( j ) );

69 }}}}


72 {{{{

73 newnewnewnew Cards().printCardsCards().printCardsCards().printCardsCards().printCards();();();();

74 } } } }

75 76 } } } } // end class Cards// end class Cards// end class Cards// end class Cards

Outline

Cards.java

King of Diamonds Jack of SpadesKing of Diamonds Jack of SpadesKing of Diamonds Jack of SpadesKing of Diamonds Jack of Spades

Four of Diamonds Six of ClubsFour of Diamonds Six of ClubsFour of Diamonds Six of ClubsFour of Diamonds Six of Clubs

King of Hearts Nine of DiamondsKing of Hearts Nine of DiamondsKing of Hearts Nine of DiamondsKing of Hearts Nine of Diamonds

Three of Spades Four of SpadesThree of Spades Four of SpadesThree of Spades Four of SpadesThree of Spades Four of Spades

Four of Hearts Seven of SpadesFour of Hearts Seven of SpadesFour of Hearts Seven of SpadesFour of Hearts Seven of Spades

Five of Diamonds Eight of HeartsFive of Diamonds Eight of HeartsFive of Diamonds Eight of HeartsFive of Diamonds Eight of Hearts

Queen of Diamonds Five of HeartsQueen of Diamonds Five of HeartsQueen of Diamonds Five of HeartsQueen of Diamonds Five of Hearts

Seven of Diamonds Seven of HeartsSeven of Diamonds Seven of HeartsSeven of Diamonds Seven of HeartsSeven of Diamonds Seven of Hearts

Nine of Hearts Three of ClubsNine of Hearts Three of ClubsNine of Hearts Three of ClubsNine of Hearts Three of Clubs

Ten of Spades Deuce of HeartsTen of Spades Deuce of HeartsTen of Spades Deuce of HeartsTen of Spades Deuce of Hearts

Three of Hearts Ace of SpadesThree of Hearts Ace of SpadesThree of Hearts Ace of SpadesThree of Hearts Ace of Spades

Six of Hearts Eight of DiamondsSix of Hearts Eight of DiamondsSix of Hearts Eight of DiamondsSix of Hearts Eight of Diamonds

Six of Diamonds Deuce of ClubsSix of Diamonds Deuce of ClubsSix of Diamonds Deuce of ClubsSix of Diamonds Deuce of Clubs

Ace of Clubs Ten of DiamondsAce of Clubs Ten of DiamondsAce of Clubs Ten of DiamondsAce of Clubs Ten of Diamonds

Eight of Clubs Queen of HeartsEight of Clubs Queen of HeartsEight of Clubs Queen of HeartsEight of Clubs Queen of Hearts

Jack of Clubs Ten of ClubsJack of Clubs Ten of ClubsJack of Clubs Ten of ClubsJack of Clubs Ten of Clubs

Seven of Clubs Queen of SpadesSeven of Clubs Queen of SpadesSeven of Clubs Queen of SpadesSeven of Clubs Queen of Spades

Five of Clubs Six of SpadesFive of Clubs Six of SpadesFive of Clubs Six of SpadesFive of Clubs Six of Spades

Nine of Spades Nine of ClubsNine of Spades Nine of ClubsNine of Spades Nine of ClubsNine of Spades Nine of Clubs

King of Spades Ace of DiamondsKing of Spades Ace of DiamondsKing of Spades Ace of DiamondsKing of Spades Ace of Diamonds

Ten of Hearts Ace of HeartsTen of Hearts Ace of HeartsTen of Hearts Ace of HeartsTen of Hearts Ace of Hearts

Queen of Clubs Deuce of SpadesQueen of Clubs Deuce of SpadesQueen of Clubs Deuce of SpadesQueen of Clubs Deuce of Spades

Three of Diamonds King of ClubsThree of Diamonds King of ClubsThree of Diamonds King of ClubsThree of Diamonds King of Clubs

Four of Clubs Jack of DiamondsFour of Clubs Jack of DiamondsFour of Clubs Jack of DiamondsFour of Clubs Jack of Diamonds

Eight of Spades Five of SpadesEight of Spades Five of SpadesEight of Spades Five of SpadesEight of Spades Five of Spades

Jack of Hearts Deuce of DiamondsJack of Hearts Deuce of DiamondsJack of Hearts Deuce of DiamondsJack of Hearts Deuce of Diamonds

378.6.3 Algorithms reverse, fill, copy, maxand min

• reverse– Reverses the order of List elements

• fill– Populates List elements with values

• copy– Creates copy of a List

• max– Returns largest element in List

• min– Returns smallest element in List

Outline

Algorithms1.java

Line 19

Line 23

1 //////// Algorithms1.javaAlgorithms1.javaAlgorithms1.javaAlgorithms1.java

2 // Using algorithms reverse, fill, copy, min and max.// Using algorithms reverse, fill, copy, min and max.// Using algorithms reverse, fill, copy, min and max.// Using algorithms reverse, fill, copy, min and max.


4 5 publicpublicpublicpublic classclassclassclass Algorithms1 {Algorithms1 {Algorithms1 {Algorithms1 {

6 privateprivateprivateprivate String letters[] = { String letters[] = { String letters[] = { String letters[] = { "P""P""P""P", , , , "C""C""C""C", , , , "M""M""M""M" }, }, }, }, lettersCopylettersCopylettersCopylettersCopy[];[];[];[];

7 privateprivateprivateprivate List list, List list, List list, List list, copyListcopyListcopyListcopyList;;;;

8 9 // create a List and manipulate it with methods from Collections// create a List and manipulate it with methods from Collections// create a List and manipulate it with methods from Collections// create a List and manipulate it with methods from Collections

10 publicpublicpublicpublic Algorithms1()Algorithms1()Algorithms1()Algorithms1()

11 {{{{

12 list = list = list = list = Arrays.asListArrays.asListArrays.asListArrays.asList( letters ); ( letters ); ( letters ); ( letters ); // get List// get List// get List// get List

13 lettersCopylettersCopylettersCopylettersCopy = = = = newnewnewnew String[ String[ String[ String[ 3333 ];];];];

14 copyListcopyListcopyListcopyList = = = = Arrays.asListArrays.asListArrays.asListArrays.asList( ( ( ( lettersCopylettersCopylettersCopylettersCopy ););););

15 16 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "Initial list: ""Initial list: ""Initial list: ""Initial list: " ););););

17 output( list );output( list );output( list );output( list );

18 19 Collections.reverse( list ); Collections.reverse( list ); Collections.reverse( list ); Collections.reverse( list ); // reverse order// reverse order// reverse order// reverse order

20 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"\\\\nAfternAfternAfternAfter calling reverse: "calling reverse: "calling reverse: "calling reverse: " ););););


22 23 Collections.copy( Collections.copy( Collections.copy( Collections.copy( copyListcopyListcopyListcopyList, list ); , list ); , list ); , list ); // copy List// copy List// copy List// copy List

24 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"\\\\nAfternAfternAfternAfter copying: "copying: "copying: "copying: " ););););

25 output( output( output( output( copyListcopyListcopyListcopyList ););););

26

Outline

Algorithms1.java

Line 27

Line 41

Line 42

27 Collections.fill( list, Collections.fill( list, Collections.fill( list, Collections.fill( list, "R""R""R""R" ); ); ); ); // fill list with // fill list with // fill list with // fill list with RsRsRsRs

28 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"\\\\nAfternAfternAfternAfter calling fill: "calling fill: "calling fill: "calling fill: " ););););


30 31 } } } } // end constructor// end constructor// end constructor// end constructor

32 33 // output List information// output List information// output List information// output List information

34 privateprivateprivateprivate voidvoidvoidvoid output( List output( List output( List output( List listReflistReflistReflistRef ))))

35 {{{{

36 System.out.print( System.out.print( System.out.print( System.out.print( "The list is: ""The list is: ""The list is: ""The list is: " ););););

37 38 forforforfor ( ( ( ( intintintint k = k = k = k = 0000; k < ; k < ; k < ; k < listRef.sizelistRef.sizelistRef.sizelistRef.size(); k++ )(); k++ )(); k++ )(); k++ )

39 System.out.print( System.out.print( System.out.print( System.out.print( listRef.getlistRef.getlistRef.getlistRef.get( k ) + ( k ) + ( k ) + ( k ) + " "" "" "" " ););););

40 41 System.out.print( System.out.print( System.out.print( System.out.print( """"\\\\nMaxnMaxnMaxnMax: ": ": ": " + Collections.max( + Collections.max( + Collections.max( + Collections.max( listReflistReflistReflistRef ) );) );) );) );

42 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( " Min: "" Min: "" Min: "" Min: " + Collections.min( + Collections.min( + Collections.min( + Collections.min( listReflistReflistReflistRef ) );) );) );) );

43 }}}}


46 {{{{

47 newnewnewnew Algorithms1();Algorithms1();Algorithms1();Algorithms1();

48 } } } }

49 50 } } } } // end class Algorithms1// end class Algorithms1// end class Algorithms1// end class Algorithms1

Outline

Algorithms1.java

Initial list:Initial list:Initial list:Initial list:The list is: P C MThe list is: P C MThe list is: P C MThe list is: P C MMax: P Min: CMax: P Min: CMax: P Min: CMax: P Min: C

After calling reverse:After calling reverse:After calling reverse:After calling reverse:The list is: M C PThe list is: M C PThe list is: M C PThe list is: M C PMax: P Min: CMax: P Min: CMax: P Min: CMax: P Min: C

After copying:After copying:After copying:After copying:The list is: M C PThe list is: M C PThe list is: M C PThe list is: M C PMax: P Min: CMax: P Min: CMax: P Min: CMax: P Min: C

After calling fill:After calling fill:After calling fill:After calling fill:The list is: R R RThe list is: R R RThe list is: R R RThe list is: R R RMax: R Min: RMax: R Min: RMax: R Min: RMax: R Min: R

41

8.6.4 Algorithm binarySearch

• binarySearch– Locates Object in List

• Returns index of Object in List if Object exists

• Returns negative value if Object does not exist

Outline

BinarySearchTest.java

Line 14

1 // // // // BinarySearchTest.javaBinarySearchTest.javaBinarySearchTest.javaBinarySearchTest.java

2 // Using algorithm // Using algorithm // Using algorithm // Using algorithm binarySearchbinarySearchbinarySearchbinarySearch....


4 5 publicpublicpublicpublic classclassclassclass BinarySearchTestBinarySearchTestBinarySearchTestBinarySearchTest {{{{

6 privateprivateprivateprivate staticstaticstaticstatic finalfinalfinalfinal String colors[] = { String colors[] = { String colors[] = { String colors[] = { "red""red""red""red", , , , "white""white""white""white", , , ,

7 "blue""blue""blue""blue", , , , "black""black""black""black", , , , "yellow""yellow""yellow""yellow", , , , "purple""purple""purple""purple", , , , "tan""tan""tan""tan", , , , "pink""pink""pink""pink" };};};};

8 privateprivateprivateprivate List list; List list; List list; List list; // List reference// List reference// List reference// List reference

9 10 // create, sort and output list // create, sort and output list // create, sort and output list // create, sort and output list

11 publicpublicpublicpublic BinarySearchTestBinarySearchTestBinarySearchTestBinarySearchTest()()()()

12 {{{{

13 list = list = list = list = newnewnewnew ArrayListArrayListArrayListArrayList( ( ( ( Arrays.asListArrays.asListArrays.asListArrays.asList( colors ) ); ( colors ) ); ( colors ) ); ( colors ) );

14 Collections.sort( list ); Collections.sort( list ); Collections.sort( list ); Collections.sort( list ); // sort the // sort the // sort the // sort the ArrayListArrayListArrayListArrayList

15 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "Sorted "Sorted "Sorted "Sorted ArrayListArrayListArrayListArrayList: ": ": ": " + list );+ list );+ list );+ list );

16 }}}}

17 18 // search list for various values// search list for various values// search list for various values// search list for various values

19 privateprivateprivateprivate voidvoidvoidvoid printSearchResultsprintSearchResultsprintSearchResultsprintSearchResults()()()()

20 {{{{

21 printSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelper( colors[ ( colors[ ( colors[ ( colors[ 3333 ] ); ] ); ] ); ] ); // first item// first item// first item// first item

22 printSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelper( colors[ ( colors[ ( colors[ ( colors[ 0000 ] ); ] ); ] ); ] ); // middle item// middle item// middle item// middle item

23 printSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelper( colors[ ( colors[ ( colors[ ( colors[ 7777 ] ); ] ); ] ); ] ); // last item// last item// last item// last item

24 printSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelper( ( ( ( "aardvark""aardvark""aardvark""aardvark" ); ); ); ); // below lowest// below lowest// below lowest// below lowest

25 printSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelper( ( ( ( "goat""goat""goat""goat" ); ); ); ); // does not exist// does not exist// does not exist// does not exist

26 printSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelper( ( ( ( "zebra""zebra""zebra""zebra" ); ); ); ); // does not exist// does not exist// does not exist// does not exist

27 }}}}

28

Outline

BinarySearchTest.java

Line 35

29 29 29 29 // helper method to perform searches// helper method to perform searches// helper method to perform searches// helper method to perform searches

30 30 30 30 privateprivateprivateprivate voidvoidvoidvoid printSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelperprintSearchResultsHelper( String key )( String key )( String key )( String key )

31 31 31 31 {{{{

32 32 32 32 intintintint result = result = result = result = 0000;;;;

33 33 33 33

34 34 34 34 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"\\\\nSearchingnSearchingnSearchingnSearching for: "for: "for: "for: " + key );+ key );+ key );+ key );

35 35 35 35 result = result = result = result = Collections.binarySearchCollections.binarySearchCollections.binarySearchCollections.binarySearch( list, key );( list, key );( list, key );( list, key );

36 36 36 36 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( result >= ( ( result >= ( ( result >= ( ( result >= 0000 ? ? ? ? "Found at index ""Found at index ""Found at index ""Found at index " + result :+ result :+ result :+ result :

37 37 37 37 "Not Found (""Not Found (""Not Found (""Not Found (" + result + + result + + result + + result + ")"")"")"")" ) );) );) );) );

38 38 38 38 }}}}

39 39 39 39

40 40 40 40 publicpublicpublicpublic staticstaticstaticstatic voidvoidvoidvoid main( String main( String main( String main( String argsargsargsargs[] )[] )[] )[] )

41 41 41 41 {{{{

42 42 42 42 newnewnewnew BinarySearchTest().printSearchResultsBinarySearchTest().printSearchResultsBinarySearchTest().printSearchResultsBinarySearchTest().printSearchResults();();();();

43 43 43 43 } } } }

44 44 44 44

45 45 45 45 } } } } // end class // end class // end class // end class BinarySearchTestBinarySearchTestBinarySearchTestBinarySearchTest

Sorted Sorted Sorted Sorted ArrayListArrayListArrayListArrayList: black blue pink purple red tan white yellow: black blue pink purple red tan white yellow: black blue pink purple red tan white yellow: black blue pink purple red tan white yellowSearching for: blackSearching for: blackSearching for: blackSearching for: blackFound at index 0Found at index 0Found at index 0Found at index 0

Searching for: redSearching for: redSearching for: redSearching for: redFound at index 4Found at index 4Found at index 4Found at index 4

Searching for: pinkSearching for: pinkSearching for: pinkSearching for: pinkFound at index 2Found at index 2Found at index 2Found at index 2

Searching for: aardvarkSearching for: aardvarkSearching for: aardvarkSearching for: aardvarkNot Found (Not Found (Not Found (Not Found (----1)1)1)1)

Searching for: goatSearching for: goatSearching for: goatSearching for: goatNot Found (Not Found (Not Found (Not Found (----3)3)3)3)

Searching for: zebraSearching for: zebraSearching for: zebraSearching for: zebraNot Found (Not Found (Not Found (Not Found (----9)9)9)9)

44

8.7 Sets

• Set– Collection that contains unique elements

– HashSet

• Stores elements in hash table

– TreeSet

• Stores elements in tree

Outline

SetTest.java

Line 22

1 // // // // SetTest.javaSetTest.javaSetTest.javaSetTest.java

2 // Using a // Using a // Using a // Using a HashSetHashSetHashSetHashSet to remove duplicates.to remove duplicates.to remove duplicates.to remove duplicates.


4 5 publicpublicpublicpublic classclassclassclass SetTestSetTestSetTestSetTest {{{{

6 privateprivateprivateprivate staticstaticstaticstatic finalfinalfinalfinal String colors[] = { String colors[] = { String colors[] = { String colors[] = { "red""red""red""red", , , , "white""white""white""white", , , , "blue""blue""blue""blue",,,,

7 "green""green""green""green", , , , "gray""gray""gray""gray", , , , "orange""orange""orange""orange", , , , "tan""tan""tan""tan", , , , "white""white""white""white", , , , "cyan""cyan""cyan""cyan",,,,

8 "peach""peach""peach""peach", , , , "gray""gray""gray""gray", , , , "orange""orange""orange""orange" };};};};

9 10 // create and output // create and output // create and output // create and output ArrayListArrayListArrayListArrayList

11 publicpublicpublicpublic SetTestSetTestSetTestSetTest()()()()

12 {{{{

13 List list = List list = List list = List list = newnewnewnew ArrayListArrayListArrayListArrayList( ( ( ( Arrays.asListArrays.asListArrays.asListArrays.asList( colors ) );( colors ) );( colors ) );( colors ) );

14 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"ArrayListArrayListArrayListArrayList: ": ": ": " + list );+ list );+ list );+ list );

15 printNonDuplicatesprintNonDuplicatesprintNonDuplicatesprintNonDuplicates( list );( list );( list );( list );

16 }}}}

17 18 // create set from array to eliminate duplicates// create set from array to eliminate duplicates// create set from array to eliminate duplicates// create set from array to eliminate duplicates

19 privateprivateprivateprivate voidvoidvoidvoid printNonDuplicatesprintNonDuplicatesprintNonDuplicatesprintNonDuplicates( Collection collection )( Collection collection )( Collection collection )( Collection collection )

20 {{{{

21 // create a // create a // create a // create a HashSetHashSetHashSetHashSet and obtain its and obtain its and obtain its and obtain its iteratoriteratoriteratoriterator

22 Set set = Set set = Set set = Set set = newnewnewnew HashSetHashSetHashSetHashSet( collection ); ( collection ); ( collection ); ( collection );

23 IteratorIteratorIteratorIterator iteratoriteratoriteratoriterator = = = = set.iteratorset.iteratorset.iteratorset.iterator(); (); (); ();

24 25 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( """"\\\\nNonduplicatesnNonduplicatesnNonduplicatesnNonduplicates are: "are: "are: "are: " ););););

26

Outline

SetTest.java

Lines 27-28

27 whilewhilewhilewhile ( ( ( ( iterator.hasNextiterator.hasNextiterator.hasNextiterator.hasNext() )() )() )() )

28 System.out.print( System.out.print( System.out.print( System.out.print( iterator.nextiterator.nextiterator.nextiterator.next() + () + () + () + " "" "" "" " ););););


31 }}}}


34 {{{{

35 newnewnewnew SetTestSetTestSetTestSetTest();();();();

36 } } } }

37 38 } } } } // end class // end class // end class // end class SetTestSetTestSetTestSetTest

ArrayListArrayListArrayListArrayList: [red, white, blue, green, gray, orange, tan, white, cyan, : [red, white, blue, green, gray, orange, tan, white, cyan, : [red, white, blue, green, gray, orange, tan, white, cyan, : [red, white, blue, green, gray, orange, tan, white, cyan, peach, gray, orange]peach, gray, orange]peach, gray, orange]peach, gray, orange]

NonduplicatesNonduplicatesNonduplicatesNonduplicates are:are:are:are:red cyan white tan gray green orange blue peachred cyan white tan gray green orange blue peachred cyan white tan gray green orange blue peachred cyan white tan gray green orange blue peach

Outline

SortedSetTest.java

Line 12

Line 19

Line 23

Lines 26-27

1 // // // // SortedSetTest.javaSortedSetTest.javaSortedSetTest.javaSortedSetTest.java

2 // Using // Using // Using // Using TreeSetTreeSetTreeSetTreeSet and and and and SortedSetSortedSetSortedSetSortedSet....


4 5 publicpublicpublicpublic classclassclassclass SortedSetTestSortedSetTestSortedSetTestSortedSetTest {{{{

6 privateprivateprivateprivate staticstaticstaticstatic finalfinalfinalfinal String names[] = { String names[] = { String names[] = { String names[] = { "yellow""yellow""yellow""yellow", , , , "green""green""green""green",,,,

7 "black""black""black""black", , , , "tan""tan""tan""tan", , , , "grey""grey""grey""grey", , , , "white""white""white""white", , , , "orange""orange""orange""orange", , , , "red""red""red""red", , , , "green""green""green""green" };};};};

8 9 // create a sorted set with // create a sorted set with // create a sorted set with // create a sorted set with TreeSetTreeSetTreeSetTreeSet, then manipulate it, then manipulate it, then manipulate it, then manipulate it

10 publicpublicpublicpublic SortedSetTestSortedSetTestSortedSetTestSortedSetTest()()()()

11 {{{{

12 SortedSetSortedSetSortedSetSortedSet tree = tree = tree = tree = newnewnewnew TreeSetTreeSetTreeSetTreeSet( ( ( ( Arrays.asListArrays.asListArrays.asListArrays.asList( names ) );( names ) );( names ) );( names ) );

13 14 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "set: ""set: ""set: ""set: " ););););

15 printSetprintSetprintSetprintSet( tree );( tree );( tree );( tree );

16 17 // get // get // get // get headSetheadSetheadSetheadSet based upon "orange"based upon "orange"based upon "orange"based upon "orange"

18 System.out.print( System.out.print( System.out.print( System.out.print( """"\\\\nheadSetnheadSetnheadSetnheadSet ((((\\\\"orange"orange"orange"orange\\\\"): ""): ""): ""): " ););););

19 printSetprintSetprintSetprintSet( ( ( ( tree.headSettree.headSettree.headSettree.headSet( ( ( ( "orange""orange""orange""orange" ) );) );) );) );

20 21 // get // get // get // get tailSettailSettailSettailSet based upon "orange"based upon "orange"based upon "orange"based upon "orange"

22 System.out.print( System.out.print( System.out.print( System.out.print( """"tailSettailSettailSettailSet ((((\\\\"orange"orange"orange"orange\\\\"): ""): ""): ""): " ););););

23 printSetprintSetprintSetprintSet( ( ( ( tree.tailSettree.tailSettree.tailSettree.tailSet( ( ( ( "orange""orange""orange""orange" ) );) );) );) );

24 25 // get first and last elements// get first and last elements// get first and last elements// get first and last elements

26 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "first: ""first: ""first: ""first: " + tree.first() );+ tree.first() );+ tree.first() );+ tree.first() );

27 System.out.printlnSystem.out.printlnSystem.out.printlnSystem.out.println( ( ( ( "last : ""last : ""last : ""last : " + tree.last() );+ tree.last() );+ tree.last() );+ tree.last() );

28 }}}}

29

Outline

SortedSetTest.java

Lines 35-36

30 // output set// output set// output set// output set

31 privateprivateprivateprivate voidvoidvoidvoid printSetprintSetprintSetprintSet( ( ( ( SortedSetSortedSetSortedSetSortedSet set )set )set )set )

32 {{{{

33 IteratorIteratorIteratorIterator iteratoriteratoriteratoriterator = = = = set.iteratorset.iteratorset.iteratorset.iterator();();();();

34 35 whilewhilewhilewhile ( ( ( ( iterator.hasNextiterator.hasNextiterator.hasNextiterator.hasNext() ) () ) () ) () )

36 System.out.print( System.out.print( System.out.print( System.out.print( iterator.nextiterator.nextiterator.nextiterator.next() + () + () + () + " "" "" "" " ););););


39 } } } }


42 {{{{

43 newnewnewnew SortedSetTestSortedSetTestSortedSetTestSortedSetTest();();();();

44 } } } }

45 46 } } } } // end class // end class // end class // end class SortedSetTestSortedSetTestSortedSetTestSortedSetTest

set:set:set:set:black green grey orange red tan white yellowblack green grey orange red tan white yellowblack green grey orange red tan white yellowblack green grey orange red tan white yellow

headSetheadSetheadSetheadSet ("orange"): black green grey("orange"): black green grey("orange"): black green grey("orange"): black green greytailSettailSettailSettailSet ("orange"): orange red tan white yellow("orange"): orange red tan white yellow("orange"): orange red tan white yellow("orange"): orange red tan white yellowfirst: blackfirst: blackfirst: blackfirst: blacklast : yellowlast : yellowlast : yellowlast : yellow

49

8.8 Maps

• Map– Associates keys to values

– Cannot contain duplicate keys• Called one-to-one mapping

Outline

MapTest.java

Line 21

1 // // // // WordTypeCount.javaWordTypeCount.javaWordTypeCount.javaWordTypeCount.java

2 // Program counts the number of occurrences of each word in a st// Program counts the number of occurrences of each word in a st// Program counts the number of occurrences of each word in a st// Program counts the number of occurrences of each word in a stringringringring

3 importimportimportimport java.awtjava.awtjava.awtjava.awt.*;.*;.*;.*;

4 importimportimportimport java.awt.eventjava.awt.eventjava.awt.eventjava.awt.event.*;.*;.*;.*;


6 importimportimportimport javax.swingjavax.swingjavax.swingjavax.swing.*;.*;.*;.*;

7 8 public classpublic classpublic classpublic class WordTypeCountWordTypeCountWordTypeCountWordTypeCount extendsextendsextendsextends JFrameJFrameJFrameJFrame {{{{

9 privateprivateprivateprivate JTextAreaJTextAreaJTextAreaJTextArea inputFieldinputFieldinputFieldinputField;;;;

10 privateprivateprivateprivate JLabelJLabelJLabelJLabel prompt;prompt;prompt;prompt;

11 privateprivateprivateprivate JTextAreaJTextAreaJTextAreaJTextArea display;display;display;display;

12 privateprivateprivateprivate JButtonJButtonJButtonJButton goButtongoButtongoButtongoButton;;;;

13 14 privateprivateprivateprivate Map map;Map map;Map map;Map map;

15 16 publicpublicpublicpublic WordTypeCountWordTypeCountWordTypeCountWordTypeCount()()()()

17 {{{{

18 supersupersupersuper( ( ( ( "Word Type Count""Word Type Count""Word Type Count""Word Type Count" ););););

19 inputFieldinputFieldinputFieldinputField = = = = newnewnewnew JTextAreaJTextAreaJTextAreaJTextArea( ( ( ( 3333, , , , 20202020 ););););

20 21 map = map = map = map = newnewnewnew HashMapHashMapHashMapHashMap();();();();

22 23 goButtongoButtongoButtongoButton = = = = newnewnewnew JButtonJButtonJButtonJButton( ( ( ( "Go" "Go" "Go" "Go" ););););

24 goButton.addActionListenergoButton.addActionListenergoButton.addActionListenergoButton.addActionListener((((

25

Outline

MapTest.java

26 newnewnewnew ActionListenerActionListenerActionListenerActionListener() { () { () { () { // inner class// inner class// inner class// inner class

27 28 public voidpublic voidpublic voidpublic void actionPerformedactionPerformedactionPerformedactionPerformed( ( ( ( ActionEventActionEventActionEventActionEvent event )event )event )event )

29 {{{{

30 createMapcreateMapcreateMapcreateMap();();();();

31 display.setTextdisplay.setTextdisplay.setTextdisplay.setText( ( ( ( createOutputcreateOutputcreateOutputcreateOutput() );() );() );() );

32 }}}}

33 34 } } } } // end inner class// end inner class// end inner class// end inner class

35 36 ); ); ); ); // end call to // end call to // end call to // end call to addActionListeneraddActionListeneraddActionListeneraddActionListener

37 38 prompt = prompt = prompt = prompt = newnewnewnew JLabelJLabelJLabelJLabel( ( ( ( "Enter a string:" "Enter a string:" "Enter a string:" "Enter a string:" ););););

39 display = display = display = display = newnewnewnew JTextAreaJTextAreaJTextAreaJTextArea( ( ( ( 15151515, , , , 20202020 ););););

40 display.setEditabledisplay.setEditabledisplay.setEditabledisplay.setEditable( ( ( ( falsefalsefalsefalse ););););

41 42 JScrollPaneJScrollPaneJScrollPaneJScrollPane displayScrollPanedisplayScrollPanedisplayScrollPanedisplayScrollPane = = = = newnewnewnew JScrollPaneJScrollPaneJScrollPaneJScrollPane( display );( display );( display );( display );

43 44 // add components to GUI// add components to GUI// add components to GUI// add components to GUI

45 Container container = Container container = Container container = Container container = getContentPanegetContentPanegetContentPanegetContentPane();();();();

46 container.setLayoutcontainer.setLayoutcontainer.setLayoutcontainer.setLayout( ( ( ( newnewnewnew FlowLayoutFlowLayoutFlowLayoutFlowLayout() );() );() );() );

47 container.add( prompt );container.add( prompt );container.add( prompt );container.add( prompt );

48 container.add( container.add( container.add( container.add( inputFieldinputFieldinputFieldinputField ););););

49 container.add( container.add( container.add( container.add( goButtongoButtongoButtongoButton ););););

50 container.add( container.add( container.add( container.add( displayScrollPanedisplayScrollPanedisplayScrollPanedisplayScrollPane ););););

51

Outline

MapTest.java

Line 69

Lines 72 and 75

52 52 52 52 setSizesetSizesetSizesetSize( ( ( ( 400400400400, , , , 400400400400 ););););

53 53 53 53 show();show();show();show();

54 54 54 54

55 55 55 55 } } } } // end constructor// end constructor// end constructor// end constructor

56 56 56 56

57 57 57 57 // create map from user input// create map from user input// create map from user input// create map from user input

58 58 58 58 private voidprivate voidprivate voidprivate void createMapcreateMapcreateMapcreateMap()()()()

59 59 59 59 {{{{

60 60 60 60 String input = String input = String input = String input = inputField.getTextinputField.getTextinputField.getTextinputField.getText();();();();

61 61 61 61 StringTokenizerStringTokenizerStringTokenizerStringTokenizer tokenizertokenizertokenizertokenizer = = = = newnewnewnew StringTokenizerStringTokenizerStringTokenizerStringTokenizer( input );( input );( input );( input );

62 62 62 62

63 63 63 63 whilewhilewhilewhile ( ( ( ( tokenizer.hasMoreTokenstokenizer.hasMoreTokenstokenizer.hasMoreTokenstokenizer.hasMoreTokens() ) {() ) {() ) {() ) {

64 64 64 64 String word = String word = String word = String word = tokenizer.nextToken().toLowerCasetokenizer.nextToken().toLowerCasetokenizer.nextToken().toLowerCasetokenizer.nextToken().toLowerCase(); (); (); (); // get word// get word// get word// get word

65 65 65 65

66 66 66 66 // if the map contains the word// if the map contains the word// if the map contains the word// if the map contains the word

67 67 67 67 ifififif ( ( ( ( map.containsKeymap.containsKeymap.containsKeymap.containsKey( word ) ) {( word ) ) {( word ) ) {( word ) ) {

68 68 68 68

69 69 69 69 Integer count = (Integer) map.get( word ); Integer count = (Integer) map.get( word ); Integer count = (Integer) map.get( word ); Integer count = (Integer) map.get( word ); // get value// get value// get value// get value

70 70 70 70

71 71 71 71 // increment value// increment value// increment value// increment value

72 72 72 72 map.put( word, map.put( word, map.put( word, map.put( word, newnewnewnew Integer( Integer( Integer( Integer( count.intValuecount.intValuecount.intValuecount.intValue() + () + () + () + 1111 ) );) );) );) );

73 73 73 73 }}}}

74 74 74 74 elseelseelseelse // otherwise add word with a value of 1 to map// otherwise add word with a value of 1 to map// otherwise add word with a value of 1 to map// otherwise add word with a value of 1 to map

75 75 75 75 map.put( word, map.put( word, map.put( word, map.put( word, newnewnewnew Integer( Integer( Integer( Integer( 1111 ) );) );) );) );

76 76 76 76

77 77 77 77 } } } } // end while// end while// end while// end while

78 78 78 78

79 79 79 79 } } } } // end method // end method // end method // end method createMapcreateMapcreateMapcreateMap

Outline

MapTest.java

80 81 // create string containing map values// create string containing map values// create string containing map values// create string containing map values

82 privateprivateprivateprivate String String String String createOutputcreateOutputcreateOutputcreateOutput() { () { () { () {

83 StringBufferStringBufferStringBufferStringBuffer output = output = output = output = newnewnewnew StringBufferStringBufferStringBufferStringBuffer( ( ( ( """""""" ););););

84 IteratorIteratorIteratorIterator keys = keys = keys = keys = map.keySet().iteratormap.keySet().iteratormap.keySet().iteratormap.keySet().iterator();();();();

85 86 // iterate through the keys// iterate through the keys// iterate through the keys// iterate through the keys

87 whilewhilewhilewhile ( ( ( ( keys.hasNextkeys.hasNextkeys.hasNextkeys.hasNext() ) {() ) {() ) {() ) {

88 Object Object Object Object currentKeycurrentKeycurrentKeycurrentKey = keys.next();= keys.next();= keys.next();= keys.next();

89 90 // output the key// output the key// output the key// output the key----value pairsvalue pairsvalue pairsvalue pairs

91 output.append( output.append( output.append( output.append( currentKeycurrentKeycurrentKeycurrentKey + + + + """"\\\\t"t"t"t" + + + +

92 map.get( map.get( map.get( map.get( currentKeycurrentKeycurrentKeycurrentKey ) + ) + ) + ) + """"\\\\n" )n" )n" )n" );;;;

93 }}}}

94 95 output.append( output.append( output.append( output.append( "size: " "size: " "size: " "size: " + map.size() ++ map.size() ++ map.size() ++ map.size() + """"\\\\n"n"n"n" ););););

96 output.append( output.append( output.append( output.append( """"isEmptyisEmptyisEmptyisEmpty: ": ": ": " + + + + map.isEmptymap.isEmptymap.isEmptymap.isEmpty() + () + () + () + """"\\\\n"n"n"n" ););););

97 98 return return return return output.toStringoutput.toStringoutput.toStringoutput.toString();();();();

99 100 } } } } // end method // end method // end method // end method createOutputcreateOutputcreateOutputcreateOutput

101

Outline

MapTest.java

102 public static voidpublic static voidpublic static voidpublic static void main( String main( String main( String main( String argsargsargsargs[] )[] )[] )[] )

103 {{{{

104 WordTypeCountWordTypeCountWordTypeCountWordTypeCount application = application = application = application = newnewnewnew WordTypeCountWordTypeCountWordTypeCountWordTypeCount();();();();

105 application.setDefaultCloseOperationapplication.setDefaultCloseOperationapplication.setDefaultCloseOperationapplication.setDefaultCloseOperation( ( ( ( JFrame.EXIT_ON_CLOSEJFrame.EXIT_ON_CLOSEJFrame.EXIT_ON_CLOSEJFrame.EXIT_ON_CLOSE ););););

106 }}}}

107 108 } } } } // end class // end class // end class // end class WordTypeCountWordTypeCountWordTypeCountWordTypeCount

55

8.9 Synchronization Wrappers

• Built-in collections are unsynchronized– Concurrent access to a Collection can cause errors

– Java provides synchronization wrappers to avoid this• Via set of public static methods

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8.9 Synchronization Wrappers (cont.)

publicpublicpublicpublic staticstaticstaticstatic method header Collection synchronizedCollection( Collection c ) List synchronizedList( List aList ) Set synchronizedSet( Set s ) SortedSet synchronizedSortedSet( SortedSet s ) Map synchronizedMap( Map m ) SortedMap synchronizedSortedMap( SortedMap m ) Fig. 8.15 Synchronization wrapper methods.

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8.10 Unmodifiable Wrappers

• Unmodifiable wrappers– Converting collections to unmodifiable collections

– Throw UnsorrtedOperationException if attempts are made to modify the collection

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8.10 Unmodifiable Wrappers

publicpublicpublicpublic staticstaticstaticstatic method header Collection unmodifiableCollection( Collection c ) List unmodifiableList( List aList ) Set unmodifiableSet( Set s ) SortedSet unmodifiableSortedSet( SortedSet s ) Map unmodifiableMap( Map m ) SortedMap unmodifiableSortedMap( SortedMap m ) Fig. 8.16 Unmodifiable wrapper methods.

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8.11 Abstract Implementations

• Abstract implementations– Offer “bare bones” implementation of collection interfaces

• Programmers can “flesh out” customizable implementations

– AbstractCollection

– AbstractList

– AbstractMap

– AbstractSequentialList

– AbstractSet

608.12 (Optional) Discovering Design Patterns: Design Patterns Used in

Package java.util

• Design patterns in package java.util

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8.12.1 Creational Design Patterns

• Prototype design pattern– Used when system must copy an object but cannot determine

object type until runtime

– Prototype object returns a copy of itself• Must belong to a class that implements common interface

– The interface’s implementation provides the copy

– Java API provides:

• Method clone of class java.lang.Object

• Interface java.lang.Cloneable

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8.12.2 Behavioral Design Patterns

• Iterator design pattern– Behavioral design pattern

– Allow objects to access objects from data structure without knowing that data structure’s behavior

• E.g., how the structure stores its objects

• E.g., specifics of traversing the structure

• An object can traverse a linked list and a hash table similarly

– Java provides interface java.util.Iterator

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8.12.3 Conclusion

• Design patterns described by the “Gang of Four”– Creational

– Structural

– Behavioral

• Design patterns not described by the “Gang of Four”– Concurrency patterns

– Architectural patterns

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