creating component definition

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WDJ - Using Web Dynpro Component Interface Definition

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2007 SAP AG 1

WDJ - Using Web Dynpro Component Interface Definit ion

Appl ies to:SAP WAS SP 16

Summary

This document provides detailed instructions on how to use Web Dynpro Component Interfaces in a WebDynpro Java Application. It contains step-by-step instructions for creating the component interface definitionand implementing this interface definition in the Web Dynpro component.

Author(s): Mahesh K.Company: LARSEN & TOUBRO INFOTECH Ltd.

Created on: 28 March 2007

Author Bio

Mahesh K. is a SAP NetWeaver (Web Application Development Focus JAVA) certifiedTechnical Consultant working with L&T Infotech, Mumbai, India. His SAP experience of over 2years spans various technologies such as ABAP, Web Dynpro for Java and Enterprise Portal.


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Table of Contents

Using Web Dynpro Component Interface Definition........................................................................ 1Applies to: ........................................................................................................................................ 1Summary.......................................................................................................................................... 1

Author Bio ........................................................................................................................................ 1Table of Contents ............................................................................................................................ 2Introduction ...................................................................................................................................... 3Project Structure .............................................................................................................................. 4Creating the Component Interface Definition .................................................................................. 5Implementing the Component Interface Definition .......................................................................... 7Making Use of Component Interface Definition ............................................................................. 10Result............................................................................................................................................. 15Related Content............................................................................................................................. 16Disclaimer and Liability Notice....................................................................................................... 16


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Introduction

Consider a scenario wherein there is a main component and two child components. We have to decide atruntime which component instance has to be displayed in the main component. Developing two monolithiccomponents would mean that one has to reference both the child component instances in the maincomponent.

As an alternative we can make use of Component Interface Definition. Component Interface Definition givesan abstract definition of the UI component interfaces (component interface controller and componentinterface views). Process involves creating a root component interface with an interface view and thenimplementing this interface definition in both child components. In main component we need to reference thecomponent instance of the root component interface only.

Context variables, methods and events can also be reused in different components by defining it in theinterface definition. The following example will illustrate the use of these interface definition and the reuse ofmethods and the interface views in different components. It will also show how to create component instanceat runtime using IWDComponentUsage.


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2007 SAP AG 4

Project Structure

The project DP_TutWDInterfaces consist of 3 components of the following name:

TutWDUInterfacesComp (Main component)

ChldDC1Comp

ChildDC2Comp

Name Package Assignment

Component Comp com.sap.wd.comp

View CompView com.sap.wd.< Component Name >compview

Window CompWin com.sap.wd.< Component Name >compwin

After creating the components delete the default window for the following components

ChldDC1Comp

ChildDC2Comp

as shown below


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Creating the Component Interface Definit ion

Right click on the Web Dynpro Component Interfaces and create the component interface definition asshown below

Name Package

WDCompInterf com.sap.wd.wdcompinterf

Click on the methods tab and create a method passInfo

Method Name Return type

passInfo void

Parameter Name Return type

p_Msg string

Click on the context tab and create a context variable Msg


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Right click on Interface View Definitions and create an Interface View as shown below

Name Package

ChildDCCompWin com.sap.wd.wdcompinterf


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Implementing the Component Interface Definition

Components ChldDC1Comp and ChildDC2Comp will be implementing the component interfacewdCompInterf.

Go to the Implement Interfaces part ofChildDC2Comp and right click on it to implement the interfacedefinition as shown below


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It will create a window with the same name as that of the interface view created in the Interface definition asshown below

Embed the existing view of the component in this window.

Double click on the component interface controller of the component. You can see the method passInfoimplemented in it.

Go to the implementation tab and inside the method passInfo, write the following code

/ / @@begi n j avadoc: passI nf o( ) / ** Decl ared met hod. */

d/ / @@en public void passI nf o( j ava. l ang. St r i ng p_Msg ){

/ / @@begi n passI nf o( ) / / Set t he cont ext var i abl e wi t h t he t ext passed t hr ough p_MsgwdCont ext . cur r ent Cont ext El ement ( ) . set Msg(p_Msg) ;

/ / @@end

}

Open the ChildDC2CompView and click on the properties tab. Add the component interface controller underthe required controllers


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Map the context variable Msg from the component Interface Controller to the View.

Go to the layout of the view and insert a TextView element and bind it to the context variable Msg

Repeat the same process for the component ChldDC1Comp.


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Making Use of Component Interface Definition

TutWDInertacesComp is the main component through which we display both the child components.So add the component interface definition under the used components ofTutWDInterfacesComp

Open the layout ofTutWDInterfacesCompView and add UI elements as shown below.


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Create actions for the buttons

btn_DC1 ( Create Child DC 1 )

btn_DC2 ( Create Child DC 2 )

Button ID Action Event Handler

btn_DC1 createDC1 onActioncreateDC1

btn_DC2 createDC2 onActioncreateDC2

Open the Navigation Modelerof the component and right click on the ViewContainerUIElement to embedthe interface view of the component interface definition.

Select the option Embed Interface View of a Component Instance since we are using the interface view ofthe component interface definition added under the used components.


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Select the required interface view from the list as shown below.

After adding the interface view the window will be as shown below.

Go to the properties tab of TutWDInterfacesCompView and add WDCompInterfInst (Web Dynpro componentusage) under required controller(s) of the view.


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Then click the implementation tab of the view and add the following code

/ ** The f ol l owi ng code sect i on can be used f or any J ava code that i s* not t o be vi si bl e t o ot her cont r ol l er s/ vi ews or t hat cont ai ns const r uct s

* cur r ent l y not support ed di r ect l y by Web Dynpr o ( such as i nner cl asses or* member var i abl es et c. ) . ** Note: The cont ent of t hi s sect i on i s i n no way managed/ cont r ol l ed* by t he Web Dynpro Desi gnt i me or t he Web Dynpro Runt i me.*/

/ / @@begi n ot her sI WDComponent Usage g_Usage = null;

/ / @@end

/ / @@begi n j avadoc: wdDoI ni t ( ) / ** Hook met hod cal l ed t o i ni t i al i ze cont rol l er . */

d/ / @@en public void wdDoI ni t ( ){

/ / @@begi n wdDoI ni t ( ) g_Usage = wdThi s. wdGet WDCompI nt er f I nst ComponentUsage( ) ;

/ / @@end

}

/ / @@begi n j avadoc: onAct i oncr eat eDC1(Ser ver Event ) / ** Decl ared val i dat i ng event handl er . */

/ / @@end

public voidonAct i oncr eat eDC1(com. sap. t c. webdynpr o. progmodel . api . I WDCust omEvent wdEvent )

{/ / @@begi n onAct i oncr eat eDC1(Ser verEvent )

/ / Check i f t her e i s a act i ve component of WDCompI nt er f I nst if ( g_Usage. hasAct i veComponent ( ) == true) {

/ / Del ete the act i ve component g_Usage. del et eComponent ( ) ;

}Check i f t her e i s a act i ve component of WDCompI nt er f I nst / /

if ( ! g_Usage. hasAct i veComponent ( ) ) {/ / I f no act i ve component i s t here, t hen cr eat e t he component

g_Usage. cr eat eComponent ( "com. sap. wd. chi l ddc1comp. Chl dDC1Comp") ;wdThi s. wdGet WDCompI nt er f I nst I nt erf ace( ) . passI nf o(

"Cr eat ed Chi l d DC 1") ;}

/ / @@end

}


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/ / @@begi n j avadoc: onAct i oncr eat eDC2(Ser ver Event ) / ** Decl ared val i dat i ng event handl er . */

/ / @@endpublic void

onAct i oncr eat eDC2(com. sap. t c. webdynpr o. progmodel . api . I WDCust omEvent wdEvent ){

/ / @@begi n onAct i oncr eat eDC2(Ser verEvent )

/ / Check i f t her e i s a act i ve component of WDCompI nt er f I nst if ( g_Usage. hasAct i veComponent ( ) == true) {

/ / Del ete the act i ve component g_Usage. del et eComponent ( ) ;

}/ / Check i f t her e i s a act i ve component of WDCompI nt er f I nst if ( ! g_Usage. hasAct i veComponent ( ) ) {

/ / I f no act i ve component i s t here, t hen cr eat e t he component

g_Usage. cr eat eComponent ( "com. sap. wd. chi l ddc2comp. Chi l dDC2Comp") ;wdThi s. wdGet WDCompI nt er f I nst I nt erf ace( ) . passI nf o(

"Cr eat ed Chi l d DC 2") ;}/ / @@end

}

Then deploy and run the application.


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Result

When we the run the application the following window opens up in the internet browser

When we click on button Create Child DC1, the child component DC1 is created and a message displayedas shown below

When we click on button Create Child DC2, the child component DC2 is created and a message displayedas shown below


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Related Content

Web Dynpro Component Interface Definitions in Practice

The Structural Concepts of Web Dynpro Components

Disclaimer and Liabili ty Notice

This document may discuss sample coding or other information that does not include SAP official interfacesand therefore is not supported by SAP. Changes made based on this information are not supported and canbe overwritten during an upgrade.

SAP will not be held liable for any damages caused by using or misusing the information, code or methodssuggested in this document, and anyone using these methods does so at his/her own risk.

SAP offers no guarantees and assumes no responsibility or liability of any type with respect to the content ofthis technical article or code sample, including any liability resulting from incompatibility between the contentwithin this document and the materials and services offered by SAP. You agree that you will not hold, or

seek to hold, SAP responsible or liable with respect to the content of this document.
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