2006 05 11 integrating java and dotnet

8/8/2019 2006 05 11 Integrating Java and DotNet

1/26

Integrating OpenROADwith Java and .NET

1

David Tondreau

Architect

1


2/26

Agenda

OpenROAD Server Primer

OpenROAD Servers COM Interface

OpenROAD and the Java Wrapper

2

OpenROAD and the C# Wrapper


3/26

The OpenROAD Server

Middle Tier Component

Business logic written in OpenROAD

SQL built into the language

Access multiple databases via gateways

3

-

Allows multiple thin clients

Communication via DCOM (even from OpenROAD clients!)

Business logic accessed using remote procedure calls (RPC)

Applications become highly scalable because databaseresources are shared (i.e, 1 db connection = many clients)


4/26

Partitioning OpenROAD Applications

Separation of business logic

OpenROAD user classes and 4GL procedures which contain businesslogic are placed in a separate application

May need to separate business logic from user interface logic!

Creation of remote procedure calls

4

4GL procedures (called Service Call Procedures or SCPs) are createdmanually or generated

SCPs allow methods of server-based user classes to be called remotely

Deployment

The server application is imaged

The application is registered in the server as a logically named resource

VASA stores registration information in the Windows registry


5/26

Client Access to the OpenROAD Server

Support OpenROAD

and COM clients

All clients follow threeOpenROAD Server Pooler

DCOM

OpenROAD Server

Client

DCOM

5

Connection using theName Server

One or more SCP calls

Release of connection

OpenROAD4GL Server

OpenROAD4GL Server

OpenROAD4GL Server

4GL4GL4GL

Ingres/Net

IngresDBMS

OpenROADNameServer

Registry


6/26

OpenROAD Client Access to the Server

Uc_Name_Server_Client 4GL Class

Provides the functions to connect and disconnect to the server Connect() and Disconnect()

Global instance (ASONameServer) declared in the runtime

RemoteServer System Class

6

Holds the connection to the to the server Provides the function to call server SCPs

Call4GL()

Provides low level means to connect (not recommended!) Initiate()

Global instance (CurRemoteServer) declared in the runtime Handles parameters to remote calls automatically


7/26

Simple Example

OpenROAD User Class

Class: EmployeeObject

Attributes

EmpID, FirstName, LastName, HireDate,

7

Methods GetEmployeeData()

METHOD GetEmployeeData () =METHOD GetEmployeeData () =METHOD GetEmployeeData () =METHOD GetEmployeeData () ={{{{

SELECT :CurObject.FirstName = First_Name,SELECT :CurObject.FirstName = First_Name,SELECT :CurObject.FirstName = First_Name,SELECT :CurObject.FirstName = First_Name,:CurObject.LastName = Last_Name,:CurObject.LastName = Last_Name,:CurObject.LastName = Last_Name,:CurObject.LastName = Last_Name,:CurObject.HireDate = Hire_Date:CurObject.HireDate = Hire_Date:CurObject.HireDate = Hire_Date:CurObject.HireDate = Hire_Date

FROM EmployeeFROM EmployeeFROM EmployeeFROM EmployeeWHERE Emp_ID = :CurObject.EmpID;WHERE Emp_ID = :CurObject.EmpID;WHERE Emp_ID = :CurObject.EmpID;WHERE Emp_ID = :CurObject.EmpID;

}}}}


8/26

Simple Example

OpenROAD Fat Client

EmployeeObject EmployeeEmployeeObject EmployeeEmployeeObject EmployeeEmployeeObject Employee

On Click GoButtonOn Click GoButtonOn Click GoButtonOn Click GoButton

8

{{{{Employee.GetEmployeeData();Employee.GetEmployeeData();Employee.GetEmployeeData();Employee.GetEmployeeData();FIELD(Employee).UpdField();FIELD(Employee).UpdField();FIELD(Employee).UpdField();FIELD(Employee).UpdField();

}}}}


9/26

Simple Example

Create a new application for the server Needs to include the business objects like the EmployeeObject

Create a Service Call Procedure

Procedure EmployeeObject_GetEmployeeDataProcedure EmployeeObject_GetEmployeeDataProcedure EmployeeObject_GetEmployeeDataProcedure EmployeeObject_GetEmployeeData((((

Employee = EmployeeObject;Employee = EmployeeObject;Employee = EmployeeObject;Employee = EmployeeObject;====

9

{{{{

Employee.GetEmployeeData();Employee.GetEmployeeData();Employee.GetEmployeeData();Employee.GetEmployeeData();}}}}

Create a starting ghost framefor the application

Image the server application

Register the applicationusing VASA


10/26

Simple Example

10


11/26

Simple Example

OpenROAD Thin Client

EmployeeObject EmployeeEmployeeObject EmployeeEmployeeObject EmployeeEmployeeObject Employee

Initialize () =Initialize () =Initialize () =Initialize () ={{{{

ASONameServer.Connect(ASONameServer.Connect(ASONameServer.Connect(ASONameServer.Connect(P_V_Name = HumanResources,P_V_Name = HumanResources,P_V_Name = HumanResources,P_V_Name = HumanResources,

11

_ __ __ __ _

}}}}On Click GoButton =On Click GoButton =On Click GoButton =On Click GoButton ={{{{

CurRemoteServer.Call4GL(EmployeeObject_GetEmployeeData,CurRemoteServer.Call4GL(EmployeeObject_GetEmployeeData,CurRemoteServer.Call4GL(EmployeeObject_GetEmployeeData,CurRemoteServer.Call4GL(EmployeeObject_GetEmployeeData,Employee = BYREF(Employee))Employee = BYREF(Employee))Employee = BYREF(Employee))Employee = BYREF(Employee))

FIELD(Employee).UpdField();FIELD(Employee).UpdField();FIELD(Employee).UpdField();FIELD(Employee).UpdField();}}}}

On WindowClose =On WindowClose =On WindowClose =On WindowClose ={{{{

CurRemoteServer.Release();CurRemoteServer.Release();CurRemoteServer.Release();CurRemoteServer.Release();}}}}


12/26

COM Client Access to the Server

ASOSession Class Provides the functions to connect and disconnect from the server

Connect() and Disconnect()

Provides the function to call the server using PM CallProc()

RemoteServer Class

12

Holds the connection to the to the server Provides low level means to connect (not recommeded!)

Initiate()

Provides the function to call server SCPs Call4GL()

ParameterData Provides the functions to pack and unpack SCP parameter data

getXXX() and setXXX()


13/26


14/26

Benefits/Drawbacks of the COM Interface

Benefits

Use Microsoft Office as a client

Use ASP web server as client

14

Have to declare parameter descriptions

Have to pack/repack parameter data

COM clients mostly Windows not Unix


15/26

OpenROAD Java Wrapper

Mirrors COM components

Uses the Java Native Interface (JNI)

Same method functionality as COM components

15

Conforms to Java naming standards

Errors raise COMExceptions

Available on Unix and Windows


16/26

Java Interface Classes

com.ingres.openroad.ASOSession

Wraps an instance of the OpenROAD.RemoteServer COM class.

com.ingres.openroad.RemoteServer

Wraps an instance of the OpenROAD.RemoteServer COM class.

16

com.ingres.openroad.ParameterData Wraps an instance of the OpenROAD.ParameterData COM class

com.ingres.openroad.COMException

Class that represents COM errors

Includes a getHRESULT method so that client code can examinethe COM HRESULT value without parsing error message text.


17/26

OpenROAD vs Java Datatypes

PDO has getXXX and setXXX methods

Five basic type conversions

SmallInt/Integer ..Integer

17

.

Varchar/StringObject..String

Date...Date

LongByteObject...Byte[ ]

Data


18/26

Proxies

Classes which represent OpenROAD classes

Written in another language (e.g., Java or C#)

Same attribute names

Used for passing data to/from appserver

18

Methods to pack/unpack themselves into ParameterData

SCPs are called from an SCPCoverClass

Methods perform calls to the OpenROAD server


19/26

19


20/26


21/26

.NET Interface Classes

Ingres.OpenROAD.ParameterData

Wraps an instance of the OpenROAD.ParameterDataCOM class

The default constructor takes no arguments and creates an

21

.

An optional constructor takes a string of attributedeclarations and implicitly does the DeclareAttr calls.

Declaration string is simply a whitespace-delimited list of attrNameattrType pairs


22/26

OpenROAD vs .NET Datatypes

Unlike Java, the .NET runtime treats all types as objects

Including the basic value types, like integer or double.

.NET PDO data access methods take and return objects

No type-specific get/set methods as in Java

Caller must cast the returned object to the relevant subtype before using

22

it.

Null values

In Java, a null object reference maps to the VT_NULL VARIANT

Null OpenROAD values are represented as null Java object references.

The .NET to COM interface maps null object references to VT_EMPTY VT_NULL is mapped to a special object type of class System.DBNull.


23/26

Exception Handling

In Java, all failures from the COM interface are reportedby throwing a com.ingres.openroad.COMException will

contain the HRESULT value

The .NET COM interface is similar Uses the System.Runtime.InteropServices.COMException class.

23

However, it uses that exception class only as a last resort!!

If a .NET exception class exists that represents the meaning of aparticular HRESULT, .NET throws the .NET exception instead ofa COMException.

E.g., HRESULT 0x80070005 Access Denied is reported asSystem.UnauthorizedAccessException.

Therefore, a single catch clause for COMException will not pickup all possible HRESULT failures.


24/26

IDisposable Interface

.NET classes implement the IDisposable

interface Provides a Dispose method to release unmanaged

resources owned by the object instance

-

24

.NET. The release method provides the equivalent functionality

in the Java classes.

Requirement to call Dispose when finished using an object

instance is similar to the requirement to call release in theJava classes.


25/26

25


26/26

Proxy Generator (Java Example)

26

2006 05 11 integrating java and dotnet

Documents