LongUIOperation Executions.deactivate null pointer exception

asked 2017-12-11 19:26:43 +0800

etorrente
0 ● 1

updated 2017-12-11 19:33:01 +0800

I'm using LongUIOperation custom implementation, but, sometimes, on

Executions.deactivate(getNativeDesktop());

I receive messagebox on screen and:

dic 11, 2017 11:09:42 AM org.zkoss.zk.ui.impl.UiEngineImpl handleError GRAVE: java.lang.NullPointerException at org.apache.catalina.connector.Request.notifyAttributeAssigned(Request.java:1528) at org.apache.catalina.connector.Request.setAttribute(Request.java:1514) at org.apache.catalina.connector.RequestFacade.setAttribute(RequestFacade.java:540) at org.zkoss.zk.ui.http.ExecutionImpl.setAttribute(ExecutionImpl.java:497) at org.zkoss.zk.ui.impl.Utils.getComponentInfos(Utils.java:120) at org.zkoss.zk.ui.impl.Utils.setComponentInfo(Utils.java:129) at org.zkoss.zk.ui.impl.AbstractUiFactory.newComponent(AbstractUiFactory.java:137) at org.zkoss.zk.ui.impl.UiEngineImpl.execCreateChild0(UiEngineImpl.java:919) at org.zkoss.zk.ui.impl.UiEngineImpl.execCreateChild(UiEngineImpl.java:889) at org.zkoss.zk.ui.impl.UiEngineImpl.execCreate0(UiEngineImpl.java:776) at org.zkoss.zk.ui.impl.UiEngineImpl.access$800(UiEngineImpl.java:128) at org.zkoss.zk.ui.impl.UiEngineImpl$TemplateImpl.create(UiEngineImpl.java:2318) at org.zkoss.bind.impl.BindListitemRenderer.render(BindListitemRenderer.java:79) at org.zkoss.zul.Listbox$Renderer.render(Listbox.java:2769) at org.zkoss.zul.Listbox.doInitRenderer(Listbox.java:2584) at org.zkoss.zul.Listbox.onInitRender(Listbox.java:2537) at sun.reflect.GeneratedMethodAccessor2366.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:3146) at org.zkoss.zk.ui.AbstractComponent.service(AbstractComponent.java:3077) at org.zkoss.zk.ui.impl.EventProcessor.process(EventProcessor.java:138) at org.zkoss.zk.ui.impl.UiEngineImpl.processEvent(UiEngineImpl.java:1846) at org.zkoss.zk.ui.impl.UiEngineImpl.process(UiEngineImpl.java:1618) at org.zkoss.zk.ui.impl.UiEngineImpl.endUpdate(UiEngineImpl.java:1222) at org.zkoss.zkex.ui.comet.CometServerPush.deactivate(CometServerPush.java:522) at org.zkoss.zk.ui.impl.DesktopImpl.deactivateServerPush(DesktopImpl.java:1596) at org.zkoss.zk.ui.Executions.deactivate(Executions.java:1011) at com.ims.web.ui.GenericViewModel.deactivateNativeDesktop(GenericViewModel.java:193) at com.ims.web.zk.ui.DesktopVMLongUIOperation.run(DesktopVMLongUIOperation.java:186) at java.lang.Thread.run(Unknown Source)

Use case example: @Command
@Override public void editBaseItem() throws Exception { super.editBaseItem(); if(selectedBaseItem.getOid() == null){ initNewItem(); } final String sessionID = getSessionID(); final StaffDailyAvailabilityVM instanceVM = this; new DesktopVMLongUIOperation(this,win,Labels.getLabel("def.msg.refreshdata","Refresh data...")) { @Override protected void execute() throws InterruptedException { try { StaffDailyAvailabilityManager.evaluateStaffDailyAvailabilitySynch(selectedBaseItem, sessionID); } catch (Exception e) { logger.error(e,e); } }

        protected void onCleanup() {
            try {
                //refresh clock time list
                selectedBaseItem.getLastStaffDailyTimestampDTO();
                if(selectedBaseItem.isErrorDetected()){
                    selectedBaseItem.setCertified(false);
                }
                BindUtils.postNotifyChange(null, null, instanceVM.getSelectedBaseItem(),"lastStaffDailyTimestampDTO");
                BindUtils.postNotifyChange(null, null, instanceVM, "selectedBaseItem");
            } catch (Exception e) {
                logger.error(e,e);
            }
        };

    }.start();
}

Here the code:

public abstract class DesktopVMLongUIOperation implements Runnable { protected static final Logger logger = Logger.getLogger(DesktopVMLongUIOperation.class); private Thread thread; private AtomicBoolean cancelled = new AtomicBoolean(false); private Window win; private GenericViewModel genericViewModel;

public DesktopVMLongUIOperation(GenericViewModel genericViewModel){
    this(genericViewModel,null,"");
}

public DesktopVMLongUIOperation(GenericViewModel genericViewModel, Window win, String busyMsg){
    this.win = win;
    this.genericViewModel = genericViewModel;
    try {
        this.genericViewModel.enableServerPush(null);
        if(win != null){
            Clients.showBusy(win,busyMsg);
        }
    } catch (Exception e) {
        logger.error(e,e);
    }
}

/**
 * asynchronous callback for your long operation code
 * @throws InterruptedException
 */
protected abstract void execute() throws InterruptedException;

/**
 * optional callback method when the task has completed successfully
 */
protected void onFinish() {};
/**
 * optional callback method when the task has been cancelled or was interrupted otherwise
 */
protected void onCancel() {};
/**
 * optional callback method when the task has completed with an uncaught RuntimeException
 * @param exception
 */
protected void onException(RuntimeException exception) {
    logger.error(exception,exception);
};
/**
 * optional callback method when the task has completed (always called)
 */
protected void onCleanup() {};

/**
 * set the cancelled flag and try to interrupt the thread 
 */
public final void cancel() {
    try {
        cancelled.set(true);
        if(thread != null){
            thread.interrupt();
        }
    } catch (Throwable e) {
        logger.error(e,e);
    }
}

/**
 * check the cancelled flag
 * @return
 */
public final boolean isCancelled() {
    return cancelled.get();
}

/**
 * Checks if the task thread has been interrupted. Use this to check whether or not to exit a busy operation in case.  
 * @throws InterruptedException when the current task has been cancelled/interrupted
 */
protected final void checkCancelled() throws InterruptedException {
    try {
        if(Thread.currentThread() != this.thread) {
            throw new IllegalStateException("this method can only be called in the worker thread (i.e. during execute)");
        }
        boolean interrupted = Thread.interrupted();
        if(interrupted || cancelled.get()) {
            cancelled.set(true);
            throw new InterruptedException();
        }
    } catch (Throwable e) {
        logger.error(e,e);
    }
}

/**
 * launch the long operation
 */
public final void start() {
    try {
        thread = new Thread(this);
        thread.start();
    } catch (Throwable e) {
        logger.error(e,e);
    }
}

@Override
public final void run() {
    try {
        try {
            checkCancelled(); //avoid unnecessary execution
            execute();
            checkCancelled(); //final cancelled check before calling onFinish
            genericViewModel.activateNativeDesktop();
            logger.error("ACTIVATE: RUN");
            onFinish();
        } catch (InterruptedException e) {
            try {
                cancelled.set(true);
                genericViewModel.activateNativeDesktop();
                logger.error("ACTIVATE: INTERRUPT");
                onCancel();
            } catch (InterruptedException e1) {
                throw new RuntimeException("interrupted onCancel handling", e1);
            } catch (Exception e1) {
                logger.error(e1,e1);
            } finally {
                try {
                    genericViewModel.deactivateNativeDesktop();
                    logger.error("DEACTIVATE: INTERRUPT");
                } catch (Exception e1) {
                    logger.error(e1,e1);
                }
            }
        } catch (RuntimeException rte) {
            try {
                genericViewModel.activateNativeDesktop();
                logger.error("ACTIVATE: EXCEPTION");
                onException(rte);
            } catch (InterruptedException e1) {
                throw new RuntimeException("interrupted onException handling", e1);
            } catch (Exception e) {
                logger.error(e,e);
            } finally {
                try {
                    genericViewModel.deactivateNativeDesktop();
                    logger.error("ACTIVATE: EXCEPTION");
                } catch (Exception e) {
                    logger.error(e,e);
                }
            }
            throw rte;
        } catch (Exception e) {
            logger.error(e,e);
        } finally {
            try {
                genericViewModel.deactivateNativeDesktop();
                logger.error("DEACTIVATE: RUN");
            } catch (Exception e) {
                logger.error(e,e);
            }
        }
    } finally {
        try {
            genericViewModel.activateNativeDesktop();
            logger.error("ACTIVATE: CLEANUP");
            try {
                if(win != null){
                    Clients.clearBusy(win);
                }
            } catch (Exception e) {
                logger.error(e,e);
            }
            onCleanup();
        } catch (InterruptedException e1) {
            throw new RuntimeException("interrupted onCleanup handling", e1);
        } catch (Exception e1) {
            logger.error(e1,e1);
        } finally {
            try {
                genericViewModel.deactivateNativeDesktop();
                logger.error("DEACTIVATE: CLEANUP");
            } catch (Exception e) {
                logger.error(e,e);
            }
        }
    }
}

}

And activate deactivate code from genericViewModel:

... ... public GenericViewModel(){ nativeDesktop = Executions.getCurrent().getDesktop(); }

... ...

public boolean activateNativeDesktop() throws Exception{
    boolean res = false;
    if(getNativeDesktop() != null && getNativeDesktop().isAlive()){
        try {
            Executions.activate(getNativeDesktop());
            res = true;
        } catch (Throwable e) {
            logger.error(e,e);
            throw(e);
        }
    }else{
        throw new Exception("ZK native Desktop is null");
    }
    return res;
}

public boolean deactivateNativeDesktop() throws Exception{
    boolean res = false;
    if(getNativeDesktop() != null && getNativeDesktop().isAlive()){
        try {
            Executions.deactivate(getNativeDesktop());
            res = true;
        } catch (Throwable e) {
            logger.error(e,e);
            throw(e);
        }
    }else{
        throw new Exception("ZK native Desktop is null");
    }
    return res;
}

... ...