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Big Tree Example with static model
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‎examples/org.eclipse.jface.snippets/Eclipse JFace Snippets/org/eclipse/jface/snippets/viewers/Snippet047VirtualBigTreeViewer.java

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/*******************************************************************************
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* Copyright (c) 2006, 2016 Tom Schindl and others.
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*
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* This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License 2.0
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* which accompanies this distribution, and is available at
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* https://www.eclipse.org/legal/epl-2.0/
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*
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* SPDX-License-Identifier: EPL-2.0
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*
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* Contributors:
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* Tom Schindl - initial API and implementation
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* Lars Vogel <[email protected]> - Bug 486603
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* Wim Jongman <[email protected]> - Overhaul without preloading model
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*******************************************************************************/
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package org.eclipse.jface.snippets.viewers;
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import java.util.Random;
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import java.util.concurrent.TimeUnit;
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import java.util.concurrent.atomic.AtomicLong;
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import org.eclipse.jface.layout.GridDataFactory;
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import org.eclipse.jface.viewers.ILazyTreeContentProvider;
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import org.eclipse.jface.viewers.LabelProvider;
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import org.eclipse.jface.viewers.TreeViewer;
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import org.eclipse.swt.SWT;
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import org.eclipse.swt.layout.GridData;
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import org.eclipse.swt.layout.GridLayout;
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import org.eclipse.swt.widgets.Display;
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import org.eclipse.swt.widgets.Shell;
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import org.eclipse.swt.widgets.Text;
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/**
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* A simple TreeViewer example to demonstrate the usage of an
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* ILazyContentProvider.
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*
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*/
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public class Snippet047VirtualBigTreeViewer {
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private static final int MODEL_DEEP = 1;
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private static final int MODEL_MAX_CHILD_COUNT = 20_000;
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private static final int MODEL_MIN_CHILDS = 10;
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private static final Random RANDOM = new Random();
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private static AtomicLong rendered = new AtomicLong();
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private static AtomicLong updated = new AtomicLong();
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private static AtomicLong childcount = new AtomicLong();
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private final TreeViewer fViewer;
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private final Text fText;
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private class MyContentProvider implements ILazyTreeContentProvider {
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@Override
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public Object getParent(Object element) {
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return ((Node) element).getParent();
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}
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@Override
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public void updateChildCount(Object element, int currentChildCount) {
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childcount.incrementAndGet();
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int cc = ((Node) element).getChildCount();
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if (cc != currentChildCount) {
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fViewer.setChildCount(element, cc);
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}
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}
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@Override
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public void updateElement(Object parent, int index) {
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updated.incrementAndGet();
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Node element = ((Node) parent).getChild(index);
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fViewer.replace(parent, index, element);
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fViewer.setChildCount(element, element.getChildCount());
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}
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}
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public class Node {
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private Node[] fChildren;
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private final int fCounter;
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private final Node fParent;
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public Node(int counter, Node parent) {
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fCounter = counter;
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fParent = parent;
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}
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public Node getParent() {
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return fParent;
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}
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public Node[] getChildren() {
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return fChildren;
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}
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public Node getChild(int index) {
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if (fChildren == null) {
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return null;
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}
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return fChildren[index];
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}
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public int getChildCount() {
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if (fChildren == null) {
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return 0;
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}
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return fChildren.length;
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}
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@Override
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public String toString() {
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Node parent = getParent();
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String type = parent == null ? "Root" : parent.getParent() == null ? "Node" : "Leaf";
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return type + " " + this.fCounter + " of " + (parent == null ? "" : String.valueOf(parent.getChildCount()))
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+ " with " + getChildCount() + " childs";
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}
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}
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public Snippet047VirtualBigTreeViewer(Shell shell) {
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System.out.println("Create large model...");
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Node root = createModel();
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System.out.println("Show UI");
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fText = new Text(shell, SWT.SINGLE | SWT.LEAD | SWT.BORDER);
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fText.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
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fText.setEnabled(false);
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fViewer = new TreeViewer(shell, SWT.VIRTUAL | SWT.BORDER);
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fViewer.setLabelProvider(new LabelProvider() {
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@Override
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public String getText(Object element) {
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rendered.incrementAndGet();
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return super.getText(element);
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}
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});
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fViewer.setContentProvider(new MyContentProvider());
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fViewer.setUseHashlookup(true);
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fViewer.setInput(root);
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fViewer.getTree().setLayoutData(GridDataFactory.fillDefaults().create());
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fViewer.setChildCount(root, root.getChildCount());
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fViewer.getTree().setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
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// at this point the model only contains what is visible on the screen.
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}
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private Node createModel() {
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Node root = new Node(-1, null);
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createChilds(root, 0);
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return root;
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}
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private void createChilds(Node parent, int i) {
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if (i > MODEL_DEEP) {
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return;
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}
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int childs = RANDOM.nextInt(MODEL_MIN_CHILDS, MODEL_MAX_CHILD_COUNT);
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parent.fChildren = new Node[childs];
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for (int j = 0; j < childs; j++) {
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parent.fChildren[j] = new Node(j, parent);
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createChilds(parent.fChildren[j], i + 1);
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}
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}
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/**
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* @param args
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*/
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public static void main(String[] args) {
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Thread thread = new Thread(new Runnable() {
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@Override
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public void run() {
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try {
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long last = 0;
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while (true) {
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TimeUnit.SECONDS.sleep(1);
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long current = rendered.get();
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if (current != last) {
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last = current;
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System.out.println("Total render requests: " + current + ", " + updated.get()
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+ " update elements, " + childcount.get() + " update childcounts");
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}
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}
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} catch (InterruptedException e) {
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return;
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}
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}
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});
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thread.setDaemon(true);
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thread.start();
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Display display = new Display();
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Shell shell = new Shell(display);
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shell.setLayout(new GridLayout());
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new Snippet047VirtualBigTreeViewer(shell);
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shell.setSize(800, 600);
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shell.open();
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while (!shell.isDisposed()) {
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if (!display.readAndDispatch()) {
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display.sleep();
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}
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}
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display.dispose();
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}
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}

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