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Difference between revisions of "EDT:Accessing a service"

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::[[EDT:Resource Binding Services|Resource Binding for Services]]
 
::[[EDT:Resource Binding Services|Resource Binding for Services]]
  
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= EDT version 0.08 =
+
= EDT version 0.80 =
  
 
In EDT version 0.80, your task is to code a '''call''' statement such as this one:  
 
In EDT version 0.80, your task is to code a '''call''' statement such as this one:  
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  returning to handleResponse  
 
  returning to handleResponse  
 
  onException serviceExceptionHandler;
 
  onException serviceExceptionHandler;
−
</source>
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</source>  
  
 
== Accessing an EGL REST-RPC service (version 0.80)  ==
 
== Accessing an EGL REST-RPC service (version 0.80)  ==

Revision as of 16:23, 5 July 2012

This page contains code snippets for service access.

You can access a service from a Rich UI application or (in the future) from code generated to Java.

The details have changed in the days after version .081 Milestone 2.  The current details are outlined here:

Resource Binding for Services

EDT version 0.80

In EDT version 0.80, your task is to code a call statement such as this one: 

myBindingVar IHTTP? = Resources.getResource("binding:myResource");
call MyInterface.myOperation() using myBindingVar
 returning to myCallBackFunction
 onException myExceptionHandler;

Your call statement typically has the following aspects:

  • Invokes a specific operation by referring either to a function in a Service type or to a function prototype in an Interface type.
  • Identifies service-access details by referring to a binding variable, which is specific to a kind of service binding.  That variable includes service-access details. You might have retrieved the details from the EGL deployment descriptor and then customized them; or you might have created the details from scratch, in your code.

Otherwise, the call statement operates as follows:

  • In a Rich UI application, the statement causes an asynchronous invocation and identifies a callback function and an exception handler.
  • Outside of Rich UI (in the future), the statement causes a synchronous invocation and does not identify a callback function or exception handler. If a returned value is expected, the statement identifies a variable to receive the returned value.
    The synchronous call statement is now supported for accessing an IBM i called or service program, as described here:
         Support for IBM i.


Accessing a dedicated service (version 0.80)

You can reference a Service type... 
myBindingVar HttpProxy;
 
call MyService.functionName(InField.text) 
 using myBindingVar 
 returning to handleResponse 
 onException serviceExceptionHandler;
...in one step: 
call MyService.functionName(InField.text) 
 using new HttpProxy
 returning to handleResponse 
 onException serviceExceptionHandler;
You can reference an Interface type...
myBindingVar HttpProxy = new HttpProxy("server.MyService");
 
call IMyService.functionName(InField.text) 
 using myBindingVar 
 returning to handleResponse 
 onException serviceExceptionHandler;
...in one step:
 call IMyService.functionName(InField.text)
 using new HttpProxy("server.MyService")
 returning to handleResponse 
 onException serviceExceptionHandler;

Accessing an EGL REST-RPC service (version 0.80)

myBindingVar httpRest{@Resource {uri="binding:myEntry"}};
call IMyServiceType.calculate(myList) 
 using myBindingVar
 returning to theCallBack
 onException theExceptionHandler;

Accessing a third-party REST service (version 0.80)

 

Accessing a called or service program on IBM i (version 0.80 or beyond)

See Support for IBM i.

EDT version .7

In EDT version .7, your task follows this pattern:  declare a service-access variable and use it in a call statement.

Accessing a dedicated service (version .7)

// 1. declare the service-access variable
myService MyServiceType?{@dedicatedService}
 
// 2. call the service
call myService.theFunction() returning to theCallBack
 onException theExceptionHandler;
 
/*
 * Example: create a new EGL project for 
 * "Web 2.0 application with services". Add the
 * the Service type shown next to the server package, 
 * and add the Handler type to the client package.
 *
 * Test the example in the Rich UI Preview tab 
 * by typing valid input into the first text box; for example: 
 * 5, 12, 4
 */
 
// the file with a Service type
package server;
 
Service MyServiceType
 
 // variables and constants can be here
 
 function calculate(myScores Int[] in) returns (Decimal(4,2)) 
 numberOfScores, i, mySum Int;
 numberOfScores = myScores.getSize();
 
 for (i from 1 to numberOfScores by 1)
 mySum = myScores[i] + mySum; 
 end
 
 return(mySum/numberOfScores);
 end 
end
 
// the file with a Handler type
package client;
 
import server.MyServiceType;
import org.eclipse.edt.rui.widgets.GridLayout;
import org.eclipse.edt.rui.widgets.TextField;
import org.eclipse.edt.rui.widgets.GridLayoutData;
import dojo.widgets.DojoButton;
import dojo.widgets.DojoTextField;
 
handler MyHandler type RUIhandler{initialUI =[ui], 
 onConstructionFunction = start, 
 cssFile = "css/ProjectInEDT.7.css", 
 title = "MyHandler"}
 
 ui GridLayout{columns = 3, rows = 4, cellPadding = 4, 
 children =[myResult, myButton, scores]};
 scores TextField{layoutData = 
 new GridLayoutData{row = 2, column = 2}};
 myButton DojoButton{layoutData = 
 new GridLayoutData{row = 4, column = 2}, 
 text = "Calculate", 
 onClick ::= ui_onClick};
 myResult DojoTextField{layoutData = 
 new GridLayoutData{row = 4, column = 3}};
 
 function start()
 
 end
 
 function theExceptionHandler(exp AnyException in)
 SysLib.writeStdOut(exp.messageID + " " + exp.message);
 
 if (exp isa ServiceInvocationException)
 SysLib.writeStdOut((exp as ServiceInvocationException).detail1);
 SysLib.writeStdOut((exp as ServiceInvocationException).detail2);
 SysLib.writeStdOut((exp as ServiceInvocationException).detail3); 
 end
 end
 
 function theCallBack(retResult decimal(4, 2) in)
 myResult.text = retResult;
 end
 
 function ui_onClick(event Event in)
 
 inputLength int = scores.text.length();
 
 myDelimiters string = ", ";
 myPosition int = 1;
 myToken string;
 myList int[];
 while(myPosition < inputLength)
 myToken = StringLib.getNextToken(scores.text, 
 myPosition, myDelimiters);
 if(myToken != null)
 myList.appendElement(myToken as int);
 end
 end
 
 /************ Service access statements ***************************/ 
 
 myService MyServiceType?{@DedicatedService};
 call myService.calculate(myList) returning to theCallBack
 onException theExceptionHandler;
 
 /*******************************************************************/
 
 end
end

Accessing an EGL REST-RPC service (version .7)

Access of an EGL REST-RPC function is similar to accessing a dedicated service, but typically involves coding the variable declaration to reference an entry in the EGL deployment descriptor.

For example, you might change the previous handler to reference a deployment descriptor entry named myService. You can change the related variable declaration in one of two ways: 

myService MyServiceType?{@Resource};
 
// or 
 
myService MyServiceType?{@Resource{bindingKey="myService"}};

You can demonstrate the access of a Service type under development only after you update two aspects of your deployment descriptor: Service Deployment and Resource Bindings. For details and a look at the version .8 code syntax, see Service bindings.

To retrieve the details from the HTTP response, add a parameter of type IHTTP to the callback function: 
function theCallBack(retResult decimal(4, 2) in, myHttp IHTTP in)
 myResult.text = retResult;
 
 // display the response in JSON format
 SysLib.writeStdOut(myHttp.getResponse().body);
end

Accessing a third-party REST service (version .7)

 




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