/*******************************************************************************
* Copyright (c) 2008, 2017 Matthew Hall 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:
* Matthew Hall - initial API and implementation (bug 207858)
* Matthew Hall - bugs 226765, 239015, 222991, 263693, 263956, 226292,
* 266038
* Conrad Groth - Bug 371756
******************************************************************************/
package org.eclipse.jface.internal.databinding.viewers;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.eclipse.core.databinding.observable.IObservable;
import org.eclipse.core.databinding.observable.IObservableCollection;
import org.eclipse.core.databinding.observable.IObservablesListener;
import org.eclipse.core.databinding.observable.Observables;
import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.core.databinding.observable.masterdetail.IObservableFactory;
import org.eclipse.core.databinding.observable.masterdetail.MasterDetailObservables;
import org.eclipse.core.databinding.observable.set.IObservableSet;
import org.eclipse.core.databinding.observable.value.IObservableValue;
import org.eclipse.core.databinding.observable.value.WritableValue;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.databinding.swt.DisplayRealm;
import org.eclipse.jface.databinding.viewers.TreeStructureAdvisor;
import org.eclipse.jface.util.Util;
import org.eclipse.jface.viewers.AbstractTreeViewer;
import org.eclipse.jface.viewers.CheckboxTreeViewer;
import org.eclipse.jface.viewers.IElementComparer;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.StructuredViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.widgets.Display;
/**
* NON-API - Abstract base class for {@link ITreeContentProvider}s which use an
* {@link IObservableFactory observable collection factory} to provide the
* elements of a tree. Each observable collection obtained from the factory is
* observed such that changes in the collection are reflected in the viewer.
*
* @since 1.2
*/
public abstract class ObservableCollectionTreeContentProvider implements
ITreeContentProvider {
private Realm realm;
private Display display;
private IObservableValue viewerObservable;
/**
* Element comparer used by the viewer (may be null).
*/
protected IElementComparer comparer;
private IObservableFactory elementSetFactory;
/**
* Interfaces for sending updates to the viewer.
*/
protected TreeViewerUpdater viewerUpdater;
/**
* Observable set of all elements known to the content provider. Subclasses
* must add new elements to this set <b>before</b> adding them to the
* viewer, and must remove old elements from this set <b>after</b> removing
* them from the viewer.
*/
protected IObservableSet knownElements;
private IObservableSet unmodifiableKnownElements;
/**
* Observable set of known elements which have been realized in the viewer.
* Subclasses must add new elements to this set <b>after</b> adding them to
* the viewer, and must remove old elements from this set <b>before</b>
* removing them from the viewer.
*/
protected IObservableSet realizedElements;
private IObservableSet unmodifiableRealizedElements;
private IObservableFactory /* <IObservableCollection> */collectionFactory;
private Map /* <Object element, TreeNode node> */elementNodes;
private TreeStructureAdvisor structureAdvisor;
/**
* Constructs an ObservableCollectionTreeContentProvider using the given
* parent provider and collection factory.
*
* @param collectionFactory
* observable factory that produces an IObservableList of
* children for a given parent element.
* @param structureAdvisor
*/
protected ObservableCollectionTreeContentProvider(
IObservableFactory collectionFactory,
TreeStructureAdvisor structureAdvisor) {
this.structureAdvisor = structureAdvisor;
display = Display.getDefault();
realm = DisplayRealm.getRealm(display);
viewerObservable = new WritableValue(realm);
viewerUpdater = null;
elementSetFactory = new IObservableFactory() {
@Override
public IObservable createObservable(Object target) {
return ObservableViewerElementSet.withComparer(realm, null,
getElementComparer((Viewer) target));
}
};
knownElements = MasterDetailObservables.detailSet(viewerObservable,
elementSetFactory, null);
unmodifiableKnownElements = Observables
.unmodifiableObservableSet(knownElements);
Assert
.isNotNull(collectionFactory,
"Collection factory cannot be null"); //$NON-NLS-1$
this.collectionFactory = collectionFactory;
}
@Override
public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
if (elementNodes != null && !elementNodes.isEmpty()) {
// Ensure we flush any observable collection listeners
TreeNode[] oldNodes = new TreeNode[elementNodes.size()];
elementNodes.values().toArray(oldNodes);
for (TreeNode oldNode : oldNodes)
oldNode.dispose();
elementNodes.clear();
elementNodes = null;
}
setViewer(viewer);
knownElements.clear();
if (realizedElements != null)
realizedElements.clear();
if (newInput != null) {
getElements(newInput);
}
}
private void setViewer(Viewer viewer) {
viewerUpdater = createViewerUpdater(viewer);
comparer = getElementComparer(viewer);
elementNodes = ViewerElementMap.withComparer(comparer);
viewerObservable.setValue(viewer); // (clears knownElements)
}
private static IElementComparer getElementComparer(Viewer viewer) {
if (viewer instanceof StructuredViewer)
return ((StructuredViewer) viewer).getComparer();
return null;
}
private static TreeViewerUpdater createViewerUpdater(Viewer viewer) {
if (viewer instanceof CheckboxTreeViewer)
return new CheckboxTreeViewerUpdater((CheckboxTreeViewer) viewer);
if (viewer instanceof AbstractTreeViewer)
return new TreeViewerUpdater((AbstractTreeViewer) viewer);
throw new IllegalArgumentException(
"This content provider only works with AbstractTreeViewer"); //$NON-NLS-1$
}
@Override
public Object getParent(Object element) {
if (structureAdvisor != null) {
Object parentFromAdvisor = structureAdvisor.getParent(element);
if (parentFromAdvisor != null) {
return parentFromAdvisor;
}
}
TreeNode node = getExistingNode(element);
if (node != null)
return node.getParent();
return null;
}
@Override
public Object[] getElements(Object input) {
return getChildren(input, true);
}
@Override
public Object[] getChildren(Object element) {
return getChildren(element, false);
}
private Object[] getChildren(Object element, boolean input) {
TreeNode node = getOrCreateNode(element, input);
Object[] children = node.getChildren().toArray();
for (Object childElement : children) {
getOrCreateNode(childElement, false).addParent(element);
}
asyncUpdateRealizedElements();
return children;
}
boolean asyncUpdatePending;
Runnable asyncUpdateRunnable;
private void asyncUpdateRealizedElements() {
if (realizedElements == null)
return;
if (asyncUpdatePending)
return;
if (!realizedElements.equals(knownElements)) {
if (asyncUpdateRunnable == null) {
asyncUpdateRunnable = new Runnable() {
@Override
public void run() {
// If we've been disposed, exit early
if (knownElements == null) {
return;
}
asyncUpdatePending = false;
if (realizedElements != null) {
realizedElements.addAll(knownElements);
}
}
};
}
asyncUpdatePending = true;
display.asyncExec(asyncUpdateRunnable);
}
}
@Override
public boolean hasChildren(Object element) {
if (structureAdvisor != null) {
Boolean hasChildren = structureAdvisor.hasChildren(element);
if (hasChildren != null) {
return hasChildren.booleanValue();
}
}
return getOrCreateNode(element, false).hasChildren();
}
protected TreeNode getOrCreateNode(Object element) {
return getOrCreateNode(element, false);
}
private TreeNode getOrCreateNode(Object element, boolean input) {
TreeNode node = getExistingNode(element);
if (node == null) {
node = new TreeNode(element);
elementNodes.put(element, node);
}
// In case the input element is also a visible node in the tree.
if (!input)
knownElements.add(element);
return node;
}
protected TreeNode getExistingNode(Object element) {
TreeNode node = (TreeNode) elementNodes.get(element);
return node;
}
protected boolean isViewerDisposed() {
Viewer viewer = (Viewer) viewerObservable.getValue();
return viewer == null || viewer.getControl() == null
|| viewer.getControl().isDisposed();
}
@Override
public void dispose() {
if (elementNodes != null) {
if (!elementNodes.isEmpty()) {
TreeNode[] nodes = new TreeNode[elementNodes.size()];
elementNodes.values().toArray(nodes);
for (TreeNode node : nodes) {
node.dispose();
}
elementNodes.clear();
}
elementNodes = null;
}
if (viewerObservable != null) {
viewerObservable.dispose();
viewerObservable = null;
}
viewerUpdater = null;
comparer = null;
knownElements = null;
unmodifiableKnownElements = null;
collectionFactory = null;
asyncUpdateRunnable = null;
}
/**
* Returns the set of elements known to this content provider. Label
* providers may track this set if they need to be notified about additions
* before the viewer sees the added element, and notified about removals
* after the element was removed from the viewer. This is intended for use
* by label providers, as it will always return the items that need labels.
*
* @return unmodifiable observable set of items that will need labels
*/
public IObservableSet getKnownElements() {
return unmodifiableKnownElements;
}
/**
* Returns the set of known elements which have been realized in the viewer.
* Clients may track this set in order to perform custom actions on elements
* while they are known to be present in the viewer.
*
* @return the set of known elements which have been realized in the viewer.
* @since 1.3
*/
public IObservableSet getRealizedElements() {
if (realizedElements == null) {
realizedElements = MasterDetailObservables.detailSet(
viewerObservable, elementSetFactory, null);
unmodifiableRealizedElements = Observables
.unmodifiableObservableSet(realizedElements);
asyncUpdateRealizedElements();
}
return unmodifiableRealizedElements;
}
/**
* Returns the set of all elements that would be removed from the known
* elements set if the given elements were removed as children of the given
* parent element.
*
* @param parent
* the parent element of the elements being removed
* @param elementsToBeRemoved
* the elements being removed
* @return the set of all elements that would be removed from the known
* elements set
*/
protected Set findPendingRemovals(Object parent,
Collection elementsToBeRemoved) {
Set result = ViewerElementSet.withComparer(comparer);
Set parents = ViewerElementSet.withComparer(comparer);
parents.add(parent);
accumulatePendingRemovals(result, parents, elementsToBeRemoved);
return result;
}
private void accumulatePendingRemovals(Set removals, Set parents,
Collection elementsToRemove) {
for (Iterator it = elementsToRemove.iterator(); it.hasNext();) {
Object element = it.next();
TreeNode node = getExistingNode(element);
if (node != null) {
if (parents.containsAll(node.getParents())) {
removals.add(element);
parents.add(element);
Collection children = node.getChildren();
accumulatePendingRemovals(removals, parents, children);
}
}
}
}
/**
* Returns a listener which, when a collection change event is received,
* updates the tree viewer through the {@link #viewerUpdater} field, and
* maintains the adds and removes parents from the appropriate tree nodes.
*
* @param parentElement
* the element that is the parent element of all elements in the
* observable collection.
* @return a listener which updates the viewer when change events occur.
*/
protected abstract IObservablesListener createCollectionChangeListener(
Object parentElement);
/**
* Registers the change listener to receive change events for the specified
* observable collection.
*
* @param collection
* the collection to observe for changes
* @param listener
* the listener that will receive collection change events.
*/
protected abstract void addCollectionChangeListener(
IObservableCollection collection, IObservablesListener listener);
/**
* Unregisters the change listener from receving change events for the
* specified observable collection.
*
* @param collection
* the collection to stop observing.
* @param listener
* the listener to remove
*/
protected abstract void removeCollectionChangeListener(
IObservableCollection collection, IObservablesListener listener);
protected boolean equal(Object left, Object right) {
if (comparer == null)
return Util.equals(left, right);
return comparer.equals(left, right);
}
protected final class TreeNode {
private Object element;
private Object parent;
private Set parentSet;
private IObservableCollection children;
private IObservablesListener listener;
TreeNode(Object element) {
Assert.isNotNull(element, "element cannot be null"); //$NON-NLS-1$
this.element = element;
}
Object getElement() {
return element;
}
public void addParent(Object newParent) {
if (parent == null) {
parent = newParent;
} else if (!equal(parent, newParent)) {
if (parentSet == null) {
parentSet = ViewerElementSet.withComparer(comparer);
parentSet.add(parent);
}
parentSet.add(newParent);
}
}
public void removeParent(Object oldParent) {
if (parentSet != null) {
parentSet.remove(oldParent);
if (parentSet.isEmpty())
parentSet = null;
}
if (equal(parent, oldParent)) {
if (parentSet == null) {
parent = null;
} else {
parent = parentSet.iterator().next();
}
}
if (parent == null) {
dispose();
}
}
private Object getParent() {
return parent;
}
public Set getParents() {
if (parentSet != null)
return parentSet;
if (parent != null)
return Collections.singleton(parent);
return Collections.EMPTY_SET;
}
private void initChildren() {
if (children == null) {
children = (IObservableCollection) collectionFactory
.createObservable(element);
if (children == null) {
listener = null;
children = Observables.emptyObservableSet(realm);
} else {
Assert
.isTrue(Util.equals(realm, children.getRealm()),
"Children observable collection must be on the Display realm"); //$NON-NLS-1$
listener = createCollectionChangeListener(element);
addCollectionChangeListener(children, listener);
knownElements.addAll(children);
}
}
}
boolean hasChildren() {
initChildren();
return !children.isEmpty();
}
public Collection getChildren() {
initChildren();
return children;
}
private void dispose() {
if (element != null) {
elementNodes.remove(element);
}
if (children != null && !children.isDisposed()) {
for (Iterator iterator = children.iterator(); iterator
.hasNext();) {
TreeNode child = getExistingNode(iterator.next());
if (child != null)
child.removeParent(element);
}
if (listener != null)
removeCollectionChangeListener(children, listener);
children.dispose();
children = null;
}
element = null;
parent = null;
if (parentSet != null) {
parentSet.clear();
parentSet = null;
}
}
}
}