Check for blank input field returns NullPointerException

[Former Member]

Hi

I have used

if(wdContext.currentContextElement().getName()==null){}

this for checking blank input , but it is giving NullPointerException ; any clue.

I am using in it SAP floor plan manager architecture.

Thanks in advance

Ananda

[Former Member · Accepted solution]

I doubt that. Can you post the complete stacktrace?

Armin

[Former Member · Accepted solution]

Hi Armin. I am using SAP Floor Plan Manager infastructure for this.Is there is any special way to handle this ( Screen Validation) in FPM.Stack trace is

java.lang.NullPointerException
	at com.companyname.xss.hr.edumm.vac.overview.OverviewView.verify(OverviewView.java:145)
	at com.companyname.xss.hr.edumm.vac.overview.OverviewView.onActionsave(OverviewView.java:181)
	at com.companyname.xss.hr.edumm.vac.overview.wdp.InternalOverviewView.wdInvokeEventHandler(InternalOverviewView.java:144)
	at com.sap.tc.webdynpro.progmodel.generation.DelegatingView.invokeEventHandler(DelegatingView.java:87)
	at com.sap.tc.webdynpro.progmodel.controller.Action.fire(Action.java:67)
	at com.sap.tc.webdynpro.clientserver.task.WebDynproMainTask.handleAction(WebDynproMainTask.java:101)
	at com.sap.tc.webdynpro.clientserver.task.WebDynproMainTask.handleActionEvent(WebDynproMainTask.java:304)
	at com.sap.tc.webdynpro.clientserver.task.WebDynproMainTask.execute(WebDynproMainTask.java:649)
	at com.sap.tc.webdynpro.clientserver.cal.AbstractClient.executeTasks(AbstractClient.java:59)
	at com.sap.tc.webdynpro.clientserver.cal.ClientManager.doProcessing(ClientManager.java:248)
	at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doWebDynproProcessing(DispatcherServlet.java:154)
	at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doContent(DispatcherServlet.java:116)
	at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doPost(DispatcherServlet.java:55)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
	at com.sap.engine.services.servlets_jsp.server.HttpHandlerImpl.runServlet(HttpHandlerImpl.java:390)
	at com.sap.engine.services.servlets_jsp.server.HttpHandlerImpl.handleRequest(HttpHandlerImpl.java:264)
	at com.sap.engine.services.httpserver.server.RequestAnalizer.startServlet(RequestAnalizer.java:347)
	at com.sap.engine.services.httpserver.server.RequestAnalizer.startServlet(RequestAnalizer.java:325)
	at com.sap.engine.services.httpserver.server.RequestAnalizer.invokeWebContainer(RequestAnalizer.java:887)
	at com.sap.engine.services.httpserver.server.RequestAnalizer.handle(RequestAnalizer.java:241)
	at com.sap.engine.services.httpserver.server.Client.handle(Client.java:92)
	at com.sap.engine.services.httpserver.server.Processor.request(Processor.java:148)
	at com.sap.engine.core.service630.context.cluster.session.ApplicationSessionMessageListener.process(ApplicationSessionMessageListener.java:33)
	at com.sap.engine.core.cluster.impl6.session.MessageRunner.run(MessageRunner.java:41)
	at com.sap.engine.core.thread.impl3.ActionObject.run(ActionObject.java:37)
	at java.security.AccessController.doPrivileged(Native Method)
	at com.sap.engine.core.thread.impl3.SingleThread.execute(SingleThread.java:95)
	at com.sap.engine.core.thread.impl3.SingleThread.run(SingleThread.java:159)

Thanks

Ananda

[Former Member · Accepted solution]

Is OverviewView.java your code or framework code?

Armin

[Former Member · Accepted solution]

Hello

OverviewView.java is my View

Please help

Thanks

Ananda

[Former Member · Accepted solution]

Please post the code including the line where the exception is thrown.

Armin

[Former Member · Accepted solution]

Hi Armin

If I give some input it's navigating to the next view as expected.

Here is the code from view implementation

[code]// -

---

// This file has been generated partially by the Web Dynpro Code Generator.

// MODIFY CODE ONLY IN SECTIONS ENCLOSED BY @@begin AND @@end.

// ALL OTHER CHANGES WILL BE LOST IF THE FILE IS REGENERATED.

// -

---

package com.companyname.xss.hr.edumm.vac.overview;

//

// IMPORTANT NOTE:

// ALL IMPORT STATEMENTS MUST BE PLACED IN THE FOLLOWING SECTION ENCLOSED

// BY @@begin imports AND @@end. FURTHERMORE, THIS SECTION MUST ALWAYS CONTAIN

// AT LEAST ONE IMPORT STATEMENT (E.G. THAT FOR IPrivateOverviewView).

// OTHERWISE, USING THE ECLIPSE FUNCTION "Organize Imports" FOLLOWED BY

// A WEB DYNPRO CODE GENERATION (E.G. PROJECT BUILD) WILL RESULT IN THE LOSS

// OF IMPORT STATEMENTS.

//

//@@begin imports

import java.sql.Date;

import com.companyname.xss.hr.edumm.vac.overview.wdp.IPrivateOverviewView;

import com.sap.pcuigp.xssfpm.java.IFPM;

import com.sap.tc.webdynpro.services.message.WDMessageType;

//@@end

//@@begin documentation

//@@end

public class OverviewView

{

/**

• Logging location.

*/

private static final com.sap.tc.logging.Location logger =

com.sap.tc.logging.Location.getLocation(OverviewView.class);

static

{

//@@begin id

String id = "$Id$";

//@@end

com.sap.tc.logging.Location.getLocation("ID.com.sap.tc.webdynpro").infoT(id);

}

/**

• Private access to the generated Web Dynpro counterpart

• for this controller class. </p>

*

• Use <code>wdThis</code> to gain typed access to the context,

• to trigger navigation via outbound plugs, to get and enable/disable

• actions, fire declared events, and access used controllers and/or

• component usages.

*

• @see com.companyname.xss.hr.edumm.vac.overview.wdp.IPrivateOverviewView for more details

*/

private final IPrivateOverviewView wdThis;

/**

• Root node of this controller's context. </p>

*

• Provides typed access not only to the elements of the root node

• but also to all nodes in the context (methods node<i>XYZ</i>())

• and their currently selected element (methods current<i>XYZ</i>Element()).

• It also facilitates the creation of new elements for all nodes

• (methods create<i>XYZ</i>Element()). </p>

*

• @see com.companyname.xss.hr.edumm.vac.overview.wdp.IPrivateOverviewView.IContextNode for more details.

*/

private final IPrivateOverviewView.IContextNode wdContext;

/**

• A shortcut for <code>wdThis.wdGetAPI()</code>. </p>

• Represents the generic API of the generic Web Dynpro counterpart

• for this controller. </p>

*/

private final com.sap.tc.webdynpro.progmodel.api.IWDViewController wdControllerAPI;

/**

• A shortcut for <code>wdThis.wdGetAPI().getComponent()</code>. </p>

• Represents the generic API of the Web Dynpro component this controller

• belongs to. Can be used to access the message manager, the window manager,

• to add/remove event handlers and so on. </p>

*/

private final com.sap.tc.webdynpro.progmodel.api.IWDComponent wdComponentAPI;

public OverviewView(IPrivateOverviewView wdThis)

{

this.wdThis = wdThis;

this.wdContext = wdThis.wdGetContext();

this.wdControllerAPI = wdThis.wdGetAPI();

this.wdComponentAPI = wdThis.wdGetAPI().getComponent();

}

//@@begin javadoc:wdDoInit()

/** Hook method called to initialize controller. */

//@@end

public void wdDoInit()

{

//@@begin wdDoInit()

//@@end

}

//@@begin javadoc:wdDoExit()

/** Hook method called to clean up controller. */

//@@end

public void wdDoExit()

{

//@@begin wdDoExit()

//@@end

}

//@@begin javadoc:wdDoModifyView

/**

• Hook method called to modify a view just before rendering.

• This method conceptually belongs to the view itself, not to the

• controller (cf. MVC pattern).

• It is made static to discourage a way of programming that

• routinely stores references to UI elements in instance fields

• for access by the view controller's event handlers, and so on.

• The Web Dynpro programming model recommends that UI elements can

• only be accessed by code executed within the call to this hook method.

*

• @param wdThis Generated private interface of the view's controller, as

• provided by Web Dynpro. Provides access to the view controller's

• outgoing controller usages, etc.

• @param wdContext Generated interface of the view's context, as provided

• by Web Dynpro. Provides access to the view's data.

• @param view The view's generic API, as provided by Web Dynpro.

• Provides access to UI elements.

• @param firstTime Indicates whether the hook is called for the first time

• during the lifetime of the view.

*/

//@@end

public static void wdDoModifyView(IPrivateOverviewView wdThis, IPrivateOverviewView.IContextNode wdContext, com.sap.tc.webdynpro.progmodel.api.IWDView view, boolean firstTime)

{

//@@begin wdDoModifyView

//@@end

}

//@@begin javadoc:verify()

/** Declared method. */

//@@end

public void verify( )

{

//@@begin verify()

if(wdContext.currentContextElement().getName()==null){

fpm.getMessageManager().reportMessage(wdThis.wdGetAPI().getComponent(),

"MandatoryInput",

WDMessageType.STANDARD,

"Missing Input");

allok = false;

}

else{

allok=true;

}

//@@end

}

//@@begin javadoc:onActionsave(ServerEvent)

/** Declared validating event handler. */

//@@end

public void onActionsave(com.sap.tc.webdynpro.progmodel.api.IWDCustomEvent wdEvent )

{

//@@begin onActionsave(ServerEvent)

verify();

if(allok==true)

{

wdThis.wdGetVcOverviewController().save();

}

//@@end

}

/*

• The following code section can be used for any Java code that is

• not to be visible to other controllers/views or that contains constructs

• currently not supported directly by Web Dynpro (such as inner classes or

• member variables etc.). </p>

*

• Note: The content of this section is in no way managed/controlled

• by the Web Dynpro Designtime or the Web Dynpro Runtime.

*/

//@@begin others

IFPM fpm=null;

boolean allok;

//@@end

}

[/code]

Thanks

Ananda

[Former Member · Accepted solution]

Hi

Check these lines in ur code.

//@@begin others

<b> IFPM fpm=null;</b>

boolean allok;

//@@end

public void verify( )

{

//@@begin verify()

if(wdContext.currentContextElement().getName()==null){

<b> fpm.getMessageManager().reportMessage</b>(wdThis.wdGetAPI().getComponent(),

"MandatoryInput",

WDMessageType.STANDARD,

"Missing Input");

.....

}

u have given a null value to fpm and u havnt given any value to it anywhere. I think this must be the problem. If not give the lines 145 and 181 of ur code.

Hope this helps.

Regards,

Rathna.

[Former Member · Accepted solution]

I agree. wdContext.currentContextElement() can never be NULL.

Armin

[Former Member · Accepted solution]

Thanks Armin & Rathna

The cause of error is the IFPM=null;

I have put the verify() in Component Controller instead of view where FPM is automatically invoked by the framework thru Interface controller thereby eliminating the exception.

Regards

Ananda

[Former Member]

Hi Ananda,

In your scenario, can you tell me if you are using "name" as model attribute or value attribute in ur context. If it is a simple value attribute, better place a condition before that if statement to check if the (wdContext.currentContextElement() == null).

Also you can debug on the context element and inspect which attributes exist.

If possible please reply in details about that attribute if it is a model attribute which is mapped or binded etc..

Regards

Praveen