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/*******************************************************************************
* Copyright (c) 2011, 2013 Wind River Systems 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:
* Wind River Systems - initial API and implementation
* IBM Corporation - bug fixing
*******************************************************************************/
package org.eclipse.debug.internal.ui.viewers.model.provisional;
import java.util.HashSet;
import java.util.Set;
import org.eclipse.swt.SWT;
/**
* Tree of virtual items that is analogous to SWT's tree control. The tree is used
* by the {@link VirtualTreeModelViewer}.
*
* @see VirtualTreeModelViewer
* @since 3.8
*/
public class VirtualTree extends VirtualItem {
/**
* Lazy virtual tree does not retrieve elements or labels,
* except for the selected elements.
*/
private boolean fLazy;
private IVirtualItemValidator fValidator;
private class SelectedItemValidator implements IVirtualItemValidator {
@Override
public boolean isItemVisible(VirtualItem item) {
// visible items. For now only mark the selected items as visible.
for (int i = 0; i < fSelection.length; i++) {
VirtualItem selectionItem = fSelection[i];
while (selectionItem != null) {
if (item.equals(selectionItem)) {
return true;
}
selectionItem = selectionItem.getParent();
}
}
return false;
}
@Override
public void showItem(VirtualItem item) {
}
}
/**
* Set of listeners of the virtual tree.
*/
private Set<IVirtualItemListener> fVirtualItemListeners = new HashSet<>(1);
/**
* The currently selected items. This array contains only
* the leaf items which are selected.
*/
private VirtualItem[] fSelection = new VirtualItem[0];
/**
* Constructs the virtual tree with the given style and validator.
*
* @param style The style flag. Only SWT.VIRTUAL flag is used.
* @param validator Item validator used to determine item visibility.
*/
public VirtualTree(int style, IVirtualItemValidator validator) {
super(null, new VirtualItem.Index(0));
fLazy = (style & SWT.VIRTUAL) != 0;
if (fLazy && validator == null) {
fValidator = new SelectedItemValidator();
} else {
fValidator = validator;
}
clearNeedsLabelUpdate();
clearNeedsDataUpdate();
}
/**
* Disposes the virtual tree.
*/
@Override
public void dispose() {
super.dispose();
fVirtualItemListeners.clear();
}
@Override
public void setNeedsCountUpdate() {
super.setNeedsCountUpdate();
clearNeedsLabelUpdate();
clearNeedsDataUpdate();
}
@Override
public void setNeedsLabelUpdate() {
// no-op
}
@Override
public void setData(String key, Object data) {
super.setData(key, data);
if (data == null) {
clearNeedsDataUpdate();
}
}
/**
* Adds a listener for when virtual items are revealed in the view.
* @param listener Listener to add to list of listeners.
*/
public void addItemListener(IVirtualItemListener listener) {
fVirtualItemListeners.add(listener);
}
public void removeItemListener(IVirtualItemListener listener) {
fVirtualItemListeners.remove(listener);
}
public VirtualItem[] getSelection() {
return fSelection;
}
public void setSelection(VirtualItem[] items) {
fSelection = items;
}
public void showItem(VirtualItem item) {
if (fValidator != null) {
fValidator.showItem(item);
}
}
public void fireItemDisposed(VirtualItem item) {
for (IVirtualItemListener listener : fVirtualItemListeners) {
listener.disposed(item);
}
}
public void fireItemRevealed(VirtualItem item) {
for (IVirtualItemListener listener : fVirtualItemListeners) {
listener.revealed(item);
}
}
@Override
public void setData(Object data) {
super.setData(data);
// The root item always has children as long as the input is non-null,
// so that it should be expanded.
setHasItems(data != null);
}
@Override
public void setHasItems(boolean hasChildren) {
super.setHasItems(hasChildren);
// The root item is always expanded as long as it has children.
if (hasChildren) {
setExpanded(true);
}
}
/**
* Returns whether the given item is considered visible by the tree as
* determined by its virtual item validator.
*
* @param item Item to check.
* @return true if items is vislble.
* @see IVirtualItemValidator
*/
public boolean isItemVisible(VirtualItem item) {
if (fLazy) {
return fValidator.isItemVisible(item);
}
return true;
}
/**
* Validates the entire tree.
*/
public void validate() {
validate(VirtualTree.this);
}
/**
* Validates the item and its children, identifying children which were
* revealed and need to be updated.
*
* @param item The item which to validate.
*/
public void validate(VirtualItem item) {
if (item.needsDataUpdate()) {
if (isItemVisible(item)) {
fireItemRevealed(item);
}
} else if (item.getData() != null) {
if ( item.needsLabelUpdate() || (item.needsCountUpdate() && item.hasItems() && item.getExpanded()) ) {
if (isItemVisible(item)) {
fireItemRevealed(item);
}
}
if (item.getData() != null && item.getItemCount() > 0 && item.getExpanded()) {
for (int i = 0; i < item.getItemCount(); i++) {
validate(item.getItem(new Index(i)));
}
}
}
}
}
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