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EDT:Accessing a service
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.
You can set up your code so that the service is at one time a dedicated service and at another an EGL REST-RPC service. The task is as follows:
- Declare a binding variable.
- Use it in a call statement.
- Define an entry in the EGL deployment descriptor. You might vary the entry or use a same-named entry in a different deployment descriptor.
Accessing a dedicated service
/******************************************************** * Declare the binding variable * ********************************************************/ myBinding IHttp? = Resources.getResource("binding:myBinding"); /******************************************************** * Call the service * ********************************************************/ call MyServiceType.calculate(myList) using myBinding returning to theCallBack onException theExceptionHandler; /******************************************************** * Example: create a new EGL project for * * "Web 2.0 client 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) 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.GridLayoutData; import org.eclipse.edt.rui.widgets.TextField; import dojo.widgets.DojoButton; import dojo.widgets.DojoTextField; handler MyHandler type RUIhandler{initialUI =[ui], onConstructionFunction = start, cssFile = "css/MyClientAppWithService.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 ***************************/ myBinding IHttp? = Resources.getResource("binding:myBinding"); call MyServiceType.calculate(myList) using myBinding 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