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/*******************************************************************************
* Copyright (c) 2012 Oracle. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0, which accompanies this distribution
* and is available at http://www.eclipse.org/legal/epl-v10.html.
*
* Contributors:
* Oracle - initial API and implementation
******************************************************************************/
package org.eclipse.jpt.common.utility.internal.command;
import org.eclipse.jpt.common.utility.ExceptionHandler;
import org.eclipse.jpt.common.utility.command.NotifyingRepeatingCommand;
import org.eclipse.jpt.common.utility.command.Command;
import org.eclipse.jpt.common.utility.command.CommandExecutor;
import org.eclipse.jpt.common.utility.internal.ListenerList;
/**
* <strong>NB:</strong> If another execution cycle is initiated while we are
* notifying the command's listeners (i.e. the {@link #state} is set
* to "repeat"), the new
* execution will not start until all the listeners are notified.
* <p>
* <strong>NB2:</strong> The command's listeners can, themselves,
* trigger another execution (by directly or indirectly calling
* {@link #execute()});
* but, again, this execution will not occur until <em>after</em> all the
* listeners have been notified.
* <p>
* <strong>NB3:</strong> Along with any exceptions thrown by the wrapped
* command, any exceptions thrown by the command's listeners will
* be passed to the {@link #exceptionHandler exception handler}.
*/
public class NotifyingRepeatingCommandWrapper
extends RepeatingCommandWrapper
implements NotifyingRepeatingCommand
{
private final ListenerList<Listener> listenerList = new ListenerList<Listener>(Listener.class);
// ********** construction **********
/**
* Construct a notifying repeating command wrapper that executes the
* specified command. Any exceptions thrown by the command or listener
* will be handled by the specified exception handler.
*/
public NotifyingRepeatingCommandWrapper(Command command, ExceptionHandler exceptionHandler) {
super(command, exceptionHandler);
}
/**
* Construct a notifying repeating command wrapper that executes the specified
* command and uses the specified command executor to execute the wrapped
* command whenever it is not already executing.
* Any exceptions thrown by the command or listener will be handled by the
* specified exception handler.
*/
public NotifyingRepeatingCommandWrapper(Command command, CommandExecutor startCommandExecutor, ExceptionHandler exceptionHandler) {
super(command, startCommandExecutor, exceptionHandler);
}
// ********** listeners **********
public void addListener(Listener listener) {
this.listenerList.add(listener);
}
public void removeListener(Listener listener) {
this.listenerList.remove(listener);
}
// ********** override **********
@Override
/* private protected */ void executeCommand() {
super.executeCommand();
if (this.state.isQuiesced()) {
// hmmm - we will notify listeners even when we are "stopped"; that seems OK...
this.executionQuiesced();
}
}
/**
* Notify our listeners.
*/
private void executionQuiesced() {
for (Listener listener : this.listenerList.getListeners()) {
try {
listener.executionQuiesced(this);
} catch (Throwable ex) {
this.exceptionHandler.handleException(ex);
}
}
}
}
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