/*******************************************************************************
* Copyright (c) 2006, 2016 Tom Schindl 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:
* Tom Schindl - initial API and implementation
* Lars Vogel <Lars.Vogel@vogella.com> - Bug 486603
*******************************************************************************/
package org.eclipse.jface.snippets.viewers;
import org.eclipse.jface.viewers.ILazyTreeContentProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
/**
* A simple TreeViewer example to demonstrate usage of an ILazyContentProvider.
* Please note that you need to call viewer.setUseHasLoop(true) to enable the
* lazy lookup in the content provider
*
*/
public class Snippet047VirtualLazyTreeViewer {
private class MyContentProvider implements ILazyTreeContentProvider {
private TreeViewer viewer;
private IntermediateNode[] elements;
public MyContentProvider(TreeViewer viewer) {
this.viewer = viewer;
}
@Override
public void dispose() {
}
@Override
public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
this.elements = (IntermediateNode[]) newInput;
}
@Override
public Object getParent(Object element) {
if (element instanceof LeafNode)
return ((LeafNode) element).parent;
return elements;
}
@Override
public void updateChildCount(Object element, int currentChildCount) {
int length = 0;
if (element instanceof IntermediateNode) {
IntermediateNode node = (IntermediateNode) element;
length = node.children.length;
}
if(element == elements)
length = elements.length;
viewer.setChildCount(element, length);
}
@Override
public void updateElement(Object parent, int index) {
Object element;
if (parent instanceof IntermediateNode)
element = ((IntermediateNode) parent).children[index];
else
element = elements[index];
viewer.replace(parent, index, element);
updateChildCount(element, -1);
}
}
public class LeafNode {
public int counter;
public IntermediateNode parent;
public LeafNode(int counter, IntermediateNode parent) {
this.counter = counter;
this.parent = parent;
}
@Override
public String toString() {
return "Leaf " + this.counter;
}
}
public class IntermediateNode {
public int counter;
public LeafNode[] children = new LeafNode[0];
public IntermediateNode(int counter) {
this.counter = counter;
}
@Override
public String toString() {
return "Node " + this.counter;
}
public void generateChildren(int i) {
children = new LeafNode[i];
for (int j = 0; j < i; j++) {
children[j] = new LeafNode(j, this);
}
}
}
public Snippet047VirtualLazyTreeViewer(Shell shell) {
final TreeViewer viewer = new TreeViewer(shell, SWT.VIRTUAL | SWT.BORDER);
viewer.setLabelProvider(new LabelProvider());
viewer.setContentProvider(new MyContentProvider(viewer));
viewer.setUseHashlookup(true);
IntermediateNode[] model = createModel();
viewer.setInput(model);
viewer.getTree().setItemCount(model.length);
}
private IntermediateNode[] createModel() {
IntermediateNode[] elements = new IntermediateNode[10];
for (int i = 0; i < 10; i++) {
elements[i] = new IntermediateNode(i);
elements[i].generateChildren(1000);
}
return elements;
}
/**
* @param args
*/
public static void main(String[] args) {
Display display = new Display();
Shell shell = new Shell(display);
shell.setLayout(new FillLayout());
new Snippet047VirtualLazyTreeViewer(shell);
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
}