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/*******************************************************************************
* Copyright (c) 2008 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.equinox.internal.p2.ui.viewers;
import org.eclipse.core.runtime.ListenerList;
import org.eclipse.jface.viewers.AbstractTreeViewer;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.progress.*;
/**
* DeferredQueryTreeContentManager is an extension of DeferredTreeContentManager
* that associates pending placeholders with their parent elements, so that
* clients know when a particular parent element is finished fetching
* its contents.
*
* @since 3.4
*
*/
public class DeferredQueryTreeContentManager extends DeferredTreeContentManager {
class ElementPendingUpdateAdapter extends PendingUpdateAdapter {
Object element;
ElementPendingUpdateAdapter(Object element) {
super();
this.element = element;
}
@Override
public boolean isRemoved() {
return super.isRemoved();
}
}
Object elementRequested;
ListenerList<IDeferredQueryTreeListener> listeners;
public DeferredQueryTreeContentManager(AbstractTreeViewer viewer) {
super(viewer);
listeners = new ListenerList<IDeferredQueryTreeListener>();
}
/*
* Overridden to keep track of the current request long enough
* to put it in the pending update adapter.
* (non-Javadoc)
* @see org.eclipse.ui.progress.DeferredTreeContentManager#getChildren(java.lang.Object)
*/
@Override
public Object[] getChildren(final Object parent) {
elementRequested = parent;
return super.getChildren(parent);
}
/*
* Overridden to signal the start of a fetch
* (non-Javadoc)
* @see org.eclipse.ui.progress.DeferredTreeContentManager#startFetchingDeferredChildren(java.lang.Object, org.eclipse.ui.progress.IDeferredWorkbenchAdapter, org.eclipse.ui.progress.PendingUpdateAdapter)
*/
@Override
protected void startFetchingDeferredChildren(final Object parent, final IDeferredWorkbenchAdapter adapter, final PendingUpdateAdapter placeholder) {
if (placeholder instanceof ElementPendingUpdateAdapter)
notifyListener(true, (ElementPendingUpdateAdapter) placeholder);
super.startFetchingDeferredChildren(parent, adapter, placeholder);
}
@Override
protected void runClearPlaceholderJob(final PendingUpdateAdapter placeholder) {
if (placeholder instanceof ElementPendingUpdateAdapter) {
if (((ElementPendingUpdateAdapter) placeholder).isRemoved() || !PlatformUI.isWorkbenchRunning())
return;
notifyListener(false, (ElementPendingUpdateAdapter) placeholder);
}
super.runClearPlaceholderJob(placeholder);
}
@Override
protected PendingUpdateAdapter createPendingUpdateAdapter() {
return new ElementPendingUpdateAdapter(elementRequested);
}
public void addListener(IDeferredQueryTreeListener listener) {
if (listener != null) {
this.listeners.add(listener);
}
}
private void notifyListener(boolean starting, ElementPendingUpdateAdapter placeholder) {
if (listeners == null || listeners.isEmpty())
return;
if (starting) {
for (IDeferredQueryTreeListener deferredQueryTreeListener : listeners) {
deferredQueryTreeListener.fetchingDeferredChildren(placeholder.element, placeholder);
}
} else {
for (IDeferredQueryTreeListener deferredQueryTreeListener : listeners) {
deferredQueryTreeListener.finishedFetchingDeferredChildren(placeholder.element, placeholder);
}
}
}
}
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