org.eclipse.jface.snippets.viewers.Snippet064TreeViewerReplacingElements.java Source code

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Here is the source code for org.eclipse.jface.snippets.viewers.Snippet064TreeViewerReplacingElements.java

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/*******************************************************************************
 * Copyright (c) 2016 Conrad Groth and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     Conrad Groth - Bug 491682
 *******************************************************************************/
package org.eclipse.jface.snippets.viewers;

import java.util.Arrays;
import java.util.List;
import java.util.Random;
import java.util.concurrent.atomic.AtomicReference;

import org.eclipse.core.databinding.observable.list.IObservableList;
import org.eclipse.core.databinding.observable.list.WritableList;
import org.eclipse.jface.databinding.swt.DisplayRealm;
import org.eclipse.jface.databinding.viewers.ObservableListTreeContentProvider;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.ViewerComparator;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.KeyAdapter;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;

/**
 * A TreeViewer with observable collections as input, to demonstrate, how
 * elements are replaced, especially what happens to selected items on
 * replacement
 */
public class Snippet064TreeViewerReplacingElements {

    public Snippet064TreeViewerReplacingElements(Shell shell) {
        Random random = new Random();
        final Composite c = new Composite(shell, SWT.NONE);
        c.setLayout(new FillLayout(SWT.VERTICAL));
        Label l = new Label(c, SWT.NONE);
        l.setText(
                "The elements are ordered lexicografically, i.e. 11 comes before 2,\nPress q, to rename one root element.\nPress w, to rename one child element.");
        final TreeViewer v = new TreeViewer(c);

        // Every observable in this example gets typed as Object, since the
        // input element is an Object
        List<Object> rootElements = Arrays.asList("root 1", "root 2", "root 3");
        Object input = new Object();
        AtomicReference<IObservableList<Object>> recentlyCreatedChildList = new AtomicReference<>();
        final IObservableList<Object> rootElementList = new WritableList<>(
                DisplayRealm.getRealm(shell.getDisplay()), Arrays.asList(rootElements), String.class);
        ITreeContentProvider contentProvider = new ObservableListTreeContentProvider<>(target -> {
            if (target == input)
                return rootElementList;
            if (target.toString().startsWith("root")) {
                recentlyCreatedChildList.set(new WritableList<>(DisplayRealm.getRealm(shell.getDisplay()),
                        Arrays.asList("child 1", "child 2"), String.class));
                return recentlyCreatedChildList.get();
            }
            return null;
        }, null);
        v.setContentProvider(contentProvider);
        v.setComparator(new ViewerComparator());
        v.setInput(input);
        v.getTree().addKeyListener(new KeyAdapter() {
            @Override
            public void keyPressed(KeyEvent e) {
                // don't use 'r' and 'c', because they would iterate through the
                // root... / child... elements
                if (e.character == 'q') {
                    rootElementList.set(0, "root " + random.nextInt());
                }
                if (e.character == 'w') {
                    IObservableList<Object> childElementsList = recentlyCreatedChildList.get();
                    if (childElementsList != null) {
                        childElementsList.set(0, "child " + random.nextInt());
                    } else {
                        System.out.println("no children list present");
                    }
                }
            }
        });
    }

    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());
        new Snippet064TreeViewerReplacingElements(shell);
        shell.open();

        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }

        display.dispose();
    }
}