/*******************************************************************************
* Copyright (c) 2006 IBM Corporation and others.
* 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:
* IBM Corporation - initial API and implementation
******************************************************************************/
package org.eclipse.ui.internal.handlers;
import java.util.Iterator;
import org.eclipse.core.commands.IHandler;
import org.eclipse.core.expressions.Expression;
import org.eclipse.ui.handlers.IHandlerActivation;
import org.eclipse.ui.handlers.IHandlerService;
import org.eclipse.ui.internal.services.INestable;
/**
* <p>
* A handler service which delegates almost all responsibility to the parent
* service. It is capable of being nested inside a component that is not
* recognizable by the "sources" event mechanism. This means that the handlers
* must be activated and deactivated manually.
* </p>
* <p>
* This class is not intended for use outside of the
* <code>org.eclipse.ui.workbench</code> plug-in.
* </p>
*
* @since 3.2
*/
public final class NestableHandlerService extends SlaveHandlerService implements
INestable {
/**
* Whether the component with which this service is associated is active.
*/
private boolean active = false;
/**
* Constructs a new instance.
*
* @param parentHandlerService
* The parent handler service for this slave; must not be
* <code>null</code>.
* @param defaultExpression
* The default expression to use if none is provided. This is
* primarily used for conflict resolution. This value may be
* <code>null</code>.
*/
public NestableHandlerService(final IHandlerService parentHandlerService,
final Expression defaultExpression) {
super(parentHandlerService, defaultExpression);
}
public final void activate() {
if (active) {
return;
}
final Iterator localActivationItr = localActivationsToParentActivations
.keySet().iterator();
while (localActivationItr.hasNext()) {
final Object object = localActivationItr.next();
if (object instanceof IHandlerActivation) {
final IHandlerActivation localActivation = (IHandlerActivation) object;
final String commandId = localActivation.getCommandId();
final IHandler handler = localActivation.getHandler();
final IHandlerActivation parentActivation = parent
.activateHandler(commandId, handler, defaultExpression);
parentActivations.add(parentActivation);
localActivationsToParentActivations.put(localActivation,
parentActivation);
}
}
active = true;
}
protected final IHandlerActivation doActivation(
final IHandlerActivation localActivation) {
final IHandlerActivation parentActivation;
if (active) {
parentActivation = parent.activateHandler(localActivation);
parentActivations.add(parentActivation);
} else {
parentActivation = null;
}
localActivationsToParentActivations.put(localActivation,
parentActivation);
return localActivation;
}
public final void deactivate() {
if (!active) {
return;
}
deactivateHandlers(parentActivations);
parentActivations.clear();
final Iterator localActivationItr = localActivationsToParentActivations
.keySet().iterator();
while (localActivationItr.hasNext()) {
final Object object = localActivationItr.next();
localActivationsToParentActivations.put(object, null);
}
active = false;
}
}