org.eclipse.jface.snippets.viewers.Snippet046UpdateViewerFromBackgroundThread.java Source code

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Here is the source code for org.eclipse.jface.snippets.viewers.Snippet046UpdateViewerFromBackgroundThread.java

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/*******************************************************************************
 * Copyright (c) 2006, 2018 Tom Schindl 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:
 *     Tom Schindl - initial API and implementation
 *     Simon Scholz <simon.scholz@vogella.com> - Bug 442343
 *     Lars Vogel <Lars.Vogel@gmail.com> - Bug 510301
 *******************************************************************************/

package org.eclipse.jface.snippets.viewers;

import java.util.Random;

import org.eclipse.jface.viewers.ArrayContentProvider;
import org.eclipse.jface.viewers.ITableLabelProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.TableColumn;

/**
 * Example how to update a viewer from a long running task
 *
 * @author Tom Schindl &lt;tom.schindl@bestsolution.at&gt;
 *
 */
public class Snippet046UpdateViewerFromBackgroundThread {
    private static Image[] images;

    public class MyModel {
        public int counter;

        public boolean finished;

        public MyModel(int counter) {
            this.counter = counter;
        }

        @Override
        public String toString() {
            return "Item " + this.counter;
        }
    }

    public class MyLabelProvider extends LabelProvider implements ITableLabelProvider {

        @Override
        public Image getColumnImage(Object element, int columnIndex) {
            if (columnIndex == 0) {
                return images[((MyModel) element).finished ? 0 : 1];
            }

            return null;
        }

        @Override
        public String getColumnText(Object element, int columnIndex) {
            return "Column " + columnIndex + " => " + element;
        }

    }

    private static Image createImage(Display display, int red, int green, int blue) {
        Color color = new Color(display, red, green, blue);
        Image image = new Image(display, 10, 10);
        GC gc = new GC(image);
        gc.setBackground(color);
        gc.fillRectangle(0, 0, 10, 10);
        gc.dispose();

        return image;
    }

    public Snippet046UpdateViewerFromBackgroundThread(Shell shell) {
        final TableViewer v = new TableViewer(shell, SWT.BORDER | SWT.FULL_SELECTION);
        v.setLabelProvider(new MyLabelProvider());
        v.setContentProvider(ArrayContentProvider.getInstance());

        TableColumn column = new TableColumn(v.getTable(), SWT.NONE);
        column.setWidth(200);
        column.setText("Column 1");

        column = new TableColumn(v.getTable(), SWT.NONE);
        column.setWidth(200);
        column.setText("Column 2");

        final MyModel[] model = createModel();
        v.setInput(model);
        v.getTable().setLinesVisible(true);
        v.getTable().setHeaderVisible(true);

        Button b = new Button(shell, SWT.PUSH);
        b.setText("Start Long Task");
        b.addSelectionListener(new SelectionAdapter() {

            @Override
            public void widgetSelected(SelectionEvent e) {
                b.setText("Update running..");
                b.setEnabled(false);
                final Thread t = new Thread() {

                    @Override
                    public void run() {
                        for (int i = 0; i < model.length; i++) {
                            if (v.getTable().isDisposed()) {
                                return;
                            }
                            final int j = i;
                            v.getTable().getDisplay().asyncExec(() -> {
                                if (model[j].finished) {
                                    model[j].finished = false;
                                } else {
                                    model[j].finished = true;
                                }
                                v.update(model[j], null);
                            });
                            try {
                                Thread.sleep(new Random().nextInt(1000) + 100);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }

                        v.getTable().getDisplay().asyncExec(() -> {
                            b.setText("Start Long Task");
                            b.setEnabled(true);
                        });
                    }
                };
                t.start();
            }
        });
    }

    private MyModel[] createModel() {
        MyModel[] elements = new MyModel[10];

        for (int i = 0; i < 10; i++) {
            elements[i] = new MyModel(i);
        }

        return elements;
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        Display display = new Display();

        images = new Image[2];
        images[0] = createImage(display, 0, 255, 0);
        images[1] = createImage(display, 255, 0, 0);

        Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());
        new Snippet046UpdateViewerFromBackgroundThread(shell);
        shell.open();

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

        for (Image image : images) {
            image.dispose();
        }

        display.dispose();

    }

}