the tools used by esup-helpdesk developers: eclipse, omondo eclipseuml plugin, apache ojb jdo

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The tools used by esup-helpdesk developers:

Eclipse,Omondo EclipseUML plugin,

Apache OJB JDO

Pascal Aubry & Alexandre BoisseauIFSIC – University of Rennes 1 – May 2004

http://perso.univ-rennes1.fr/pascal.aubry/presentations/jdo

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Program.java(runtime logic)

Program.java(runtime logic)

runtime components

Program.classProgram.classjavac

user-maintained datauser-maintained data

generated datagenerated data

tools and programs

Legend:

A Java program

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Channel.java(runtime logic)


runtime components

Channel.classChannel.class

uPortal

IChannel.javaIChannel.java

javac

runtimedata

XMLoutput

impl

emen

tatio

n



tools and programs

Legend:

A uPortal channel

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runtime components

Data.classData.class

Data.java(data access)



uPortal

database


javacdatabaseaccessconfig

databaseaccessconfig

javacdatabaseaccesses

databasemanagement

runtimedata

XMLoutput

impl

emen

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tools and programs

Legend:

A uPortal channel accessing a database

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runtime components

Data.classData.class




uPortal

database





databasemanagement

runtimedata

XMLoutput

impl

emen

tatio

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tools and programs

Legend:

Accessing the database through (OJB) JDO

OJB JDOenhancer

databaseobject map

databaseobject map

JDO runtimeJDO runtime

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runtime components



Data.classData.class JDO runtimeJDO runtime

UMLmodel

UMLmodel




uPortal

database

OJB JDOenhancer

databaseobject map

databaseobject map




OmondoeclipseUML


databasemanagement

code generation &reverse engineering

runtimedata

XMLoutput

impl

emen

tatio

n



tools and programs

Legend:

Using Omondo EclipseUML plugin

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runtime components




UMLmodel

UMLmodel




uPortal

database

OJB JDOenhancer

databaseobject map

databaseobject map




OmondoeclipseUML


databasemanagement


runtimedata

XMLoutput

impl

emen

tatio

n



tools and programs

missing feature

Legend:

database object mapping

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runtime components




UMLmodel

UMLmodel




uPortal

database

OJB JDOenhancer

databaseobject map

databaseobject map




OmondoeclipseUML


databasemanagement


database object mapping

runtimedata

XMLoutput

impl

emen

tatio

n



tools and programs

missing feature

Legend:

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JDO principles

• Database abstraction– Uses JDBC– JDBC abstracts the database manager– JDO abstracts the data:

no SQL code is written at all!

• Persistence management– Perform changes on objects– the changes are automatically reflected on the

data (in the database)

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JDO specifications

• http://java.sun.com/products/jdo/index.jsp

• http://www.theserverside.com/articles/article.tss?l=JDO

• http://www.onjava.com/pub/a/onjava/excerpt/JDO_chap3/

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JDO implementations• Commercial

– Kodo JDO (SolarMetric/Versant)• the most feature complete, easy to use implementation.

– JDO Genie• pretty feature complete, but bad reputation.

– JCredo

• Open-source– OJB (Apache, open source)

• JDO support is added through a plugin. A native JDO implementation will come with JDO 2.0.

– TJDO (dead), XORM (not followed)– Castor JDO

• Last release in march 2004. Middle product– JOnAS (ObjectWeb)

• JOnAS is a J2ee specification which include JDO implementation.– Hibernate JDO (Hibernate)

• seems to be a good product– JBoss announced an open-source JDO implementation in JBoss.

• http://www.theserverside.com/discussions/thread.tss?thread_id=21825

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A very short example

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The CUser class

public class CUser {private String id;private String displayName;

public CUser(String id, String displayName) {this.id = id;this.displayName = displayName;

}public String getId() {

return id;}public String getDisplayName() {

return displayName;}

}

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The CDoc classpublic class CDoc { private long id; private java.sql.Timestamp date; private CUser sender; private String senderId;

public CDoc(String description, CUser sender) { // id is automatically set by OJB-JDO. this.date = new java.sql.Timestamp( new Date().getTime()); this.sender = sender; this.senderId = sender.getId(); }

public long getId() { return id; } public Timestamp getDate() { return date; } public CUser getSender() { return sender; }}

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CUser database mapping

<class-descriptor class="CExample.CUser" table="user"> <field-descriptor name="id" column="id" jdbc-type="VARCHAR" primarykey="true" /> <field-descriptor name="displayName" column="displayName" jdbc-type="VARCHAR"/></class-descriptor>

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CUser database mapping

Table user :

- id (primary-key)

- displayname

Table user :

- id (primary-key)

- displayname

<field-descriptor name="displayName" column="displayname" jdbc-type="VARCHAR"/>

<field-descriptor name="id" column="id" jdbc-type="VARCHAR"/>

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CDoc database mapping

<class-descriptor class="CExample.CDoc" table="doc"> <field-descriptor name="id" column="id" jdbc-type="BIGINT" primarykey="true" autoincrement="true"/> <field-descriptor name="date" column="date“ jdbc-type="TIMESTAMP"/> <field-descriptor name="senderId" column="sender" jdbc-type="VARCHAR"/> <reference-descriptor name="sender" class-ref="CExample.CUser"> <foreignkey field-ref="senderId"/> </reference-descriptor></class-descriptor>

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CDoc database mapping

Table doc :

- id (primary-key)

- date

- sender-id

Table doc :

- id (primary-key)

- date

- sender-id

Table user :

- id (primary-key)

- displayname

Table user :

- id (primary-key)

- displayname<reference-descriptor name="sender" class-ref="CExample.CUser"><foreignkey field-ref="senderId"/>

field-descriptor name="date" column="date" jdbc-type="TIMESTAMP"/>

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Programming with OJB

// Get an Persistence Manager Factory (PMF)OjbStorePMF f = new OjbStoryPMF();

// Get a Persistence ManagerPersistenceManager manager = f.getPersistenceManager();

// Start a transactionmanager.currentTransaction().begin();

//// Do things... //

// Commit or rollback the transactionmanager.currentTransaction().commit();

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Example: display all userstry { manager.currentTransaction().begin();

Query query = manager.newQuery(CUser.class);

Collection allUsers = (Collection) query.execute();

Iterator iter = allUsers.iterator(); while (iter.hasNext()) { u = (CUser) iter.next(); System.out.println("id=" + u.getId() + ", displayName=" + u.getDisplayName()); i++; }

manager.currentTransaction().commit();

} catch (Throwable t) { t.printStackTrace();

} finally { manager.close();}}

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Example: create a user

CUser u = new CUser("mon-id", "NOM prenom");

Transaction tx = manager.currentTransaction();

tx.begin();

// Mark object as persistantmanager.makePersistent(u);

try{ // Commit the transaction, object mark persistent is stored. tx.commit();

} catch(OjbStoreFatalInternalException ex){ System.out.println("User already exists!");

} finally { manager.close();}

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Example: delete a user

Transaction tx = manager.currentTransaction();tx.begin();

Query query = manager.newQuery(CUser.class, "displayName == \"Toto\""); Collection result = (Collection) query.execute();

if (result.size() == 0) { System.out.println("No user found!");} else if (result.size() > 1) { System.out.println("Several users match!");} else { CUser u = (CUser) result.iterator().next(); manager.deletePersistent(u);}tx.commit();

the tools used by esup-helpdesk developers: eclipse, omondo eclipseuml plugin, apache ojb jdo

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