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/*******************************************************************************
* Copyright (c) 2007, 2016 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 java.util.HashMap;
import java.util.HashSet;
import org.eclipse.core.runtime.ListenerList;
import org.eclipse.equinox.internal.p2.ui.model.*;
import org.eclipse.jface.viewers.AbstractTreeViewer;
import org.eclipse.jface.viewers.Viewer;
/**
* Content provider that retrieves children asynchronously where
* possible using the IDeferredWorkbenchAdapter and provisioning
* query mechanisms.
*
* @since 3.4
*
*/
public class DeferredQueryContentProvider extends ProvElementContentProvider {
DeferredQueryTreeContentManager manager;
Object currentInput;
HashMap<Object, Object> alreadyQueried = new HashMap<Object, Object>();
HashSet<Object> queryCompleted = new HashSet<Object>();
AbstractTreeViewer viewer = null;
ListenerList<IInputChangeListener> listeners = new ListenerList<IInputChangeListener>();
boolean synchronous = false;
IDeferredQueryTreeListener onFetchingActionListener;
/**
*
*/
public DeferredQueryContentProvider() {
// Default constructor
}
public void addListener(IInputChangeListener listener) {
listeners.add(listener);
}
public void removeListener(IInputChangeListener listener) {
listeners.remove(listener);
}
public void addOnFetchingActionListener(IDeferredQueryTreeListener listener) {
onFetchingActionListener = listener;
}
@Override
public void inputChanged(Viewer v, Object oldInput, Object newInput) {
super.inputChanged(v, oldInput, newInput);
if (manager != null)
manager.cancel(oldInput);
if (v instanceof AbstractTreeViewer) {
manager = new DeferredQueryTreeContentManager((AbstractTreeViewer) v);
manager.addListener(onFetchingActionListener);
viewer = (AbstractTreeViewer) v;
manager.addListener(new IDeferredQueryTreeListener() {
@Override
public void fetchingDeferredChildren(Object parent, Object placeholder) {
alreadyQueried.put(parent, placeholder);
}
@Override
public void finishedFetchingDeferredChildren(Object parent, Object placeholder) {
queryCompleted.add(parent);
}
});
} else
viewer = null;
alreadyQueried = new HashMap<Object, Object>();
queryCompleted = new HashSet<Object>();
currentInput = newInput;
for (IInputChangeListener listener : listeners) {
listener.inputChanged(v, oldInput, newInput);
}
}
@Override
public Object[] getElements(Object input) {
if (input instanceof QueriedElement) {
return getChildren(input);
}
return super.getElements(input);
}
@Override
public void dispose() {
super.dispose();
if (manager != null) {
manager.cancel(currentInput);
}
}
@Override
public boolean hasChildren(Object element) {
if (manager != null) {
if (manager.isDeferredAdapter(element))
return manager.mayHaveChildren(element);
}
return super.hasChildren(element);
}
@Override
public Object[] getChildren(final Object parent) {
if (parent instanceof RemoteQueriedElement) {
RemoteQueriedElement element = (RemoteQueriedElement) parent;
// We rely on the assumption that the queryable is the most expensive
// thing to get vs. the query itself being expensive.
// (loading a repo vs. querying a repo afterward)
if (manager != null && !synchronous && (element instanceof MetadataRepositoryElement || element instanceof MetadataRepositories)) {
if (element.getCachedChildren().length == 0)
return manager.getChildren(element);
return element.getChildren(element);
}
if (element.hasQueryable())
return element.getChildren(element);
}
return super.getChildren(parent);
}
public void setSynchronous(boolean sync) {
if (sync == true && manager != null)
manager.cancel(currentInput);
this.synchronous = sync;
}
public boolean getSynchronous() {
return synchronous;
}
}
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