net.sourceforge.docfetcher.gui.StatusBar.java Source code

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Here is the source code for net.sourceforge.docfetcher.gui.StatusBar.java

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/*******************************************************************************
 * Copyright (c) 2010, 2011 Tran Nam Quang.
 * 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:
 *    Tran Nam Quang - initial API and implementation
 *******************************************************************************/

package net.sourceforge.docfetcher.gui;

import java.util.Collections;
import java.util.List;

import net.sourceforge.docfetcher.util.Event;
import net.sourceforge.docfetcher.util.Util;
import net.sourceforge.docfetcher.util.annotations.NotNull;
import net.sourceforge.docfetcher.util.annotations.Nullable;
import net.sourceforge.docfetcher.util.gui.FormDataFactory;

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.CLabel;
import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.FormLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Shell;

import com.google.common.collect.Lists;

/**
 * A status bar widget consisting of multiple parts with the following
 * properties:
 * <ul>
 * <li>There is one left part and zero or more right parts.
 * <li>All parts have a text label and an optional image.
 * <li>The right parts can be shown and hidden.
 * </ul>
 * This class is intended to be subclassed, optionally overriding
 * {@link #createRightParts(StatusBar)}.
 * 
 * @author Tran Nam Quang
 */
public class StatusBar extends Composite {

    /**
     * A part of a status bar.
     */
    public static final class StatusBarPart {
        public final Event<Void> evtClicked;

        private final StatusBar statusBar;
        private final CLabel label;
        private boolean isVisible = true;

        public StatusBarPart(@NotNull StatusBar statusBar, boolean clickable) {
            Util.checkNotNull(statusBar);
            this.statusBar = statusBar;
            label = new CLabel(statusBar, SWT.LEFT);

            if (clickable) {
                evtClicked = new Event<Void>();
                label.addMouseListener(new MouseAdapter() {
                    public void mouseUp(MouseEvent e) {
                        evtClicked.fire(null);
                    }
                });
                Util.addMouseHighlighter(label);
            } else {
                evtClicked = null;
            }
        }

        /**
         * Returns the receiver's underlying SWT control.
         */
        @NotNull
        public Control getControl() {
            return label;
        }

        /**
         * Returns whether this part is visible.
         */
        public boolean isVisible() {
            return isVisible;
        }

        /**
         * Sets the visibility of this part. Invisible parts are excluded from
         * the layout. This method has no effect if the part is on the left side
         * of the status bar.
         */
        public void setVisible(boolean isVisible) {
            if (this.isVisible == isVisible)
                return;
            this.isVisible = isVisible;
            label.setVisible(isVisible);
            statusBar.updateLayout();
        }

        /**
         * Sets the image and text of this part. The image may be null.
         */
        public void setContents(@Nullable Image image, @NotNull String text) {
            Util.checkNotNull(text);
            label.setImage(image);
            label.setText(text);
            statusBar.updateLayout();
        }

        /**
         * Returns the image displayed on this part, which may be null.
         */
        @Nullable
        public Image getImage() {
            return label.getImage();
        }

        /**
         * Returns the text displayed on this part.
         */
        @NotNull
        public String getText() {
            return label.getText();
        }

        /**
         * Returns a rectangle describing the bounds of the receiver relative to
         * containing shell, or null if the receiver is not visible.
         */
        @Nullable
        public Rectangle getBounds() {
            if (!isVisible)
                return null;
            Shell shell = label.getShell();
            Rectangle bounds = label.getBounds();
            return shell.getDisplay().map(statusBar, shell, bounds);
        }
    }

    private final StatusBarPart leftPart;
    private final List<StatusBarPart> rightParts;

    /**
     * Creates an instance with the given parent.
     */
    public StatusBar(Composite parent) {
        super(parent, SWT.NONE);
        setLayout(new FormLayout());

        leftPart = new StatusBarPart(this, false);
        rightParts = createRightParts(this);
        Util.checkNotNull(rightParts);

        updateLayout();
    }

    /**
     * Returns the left part.
     */
    public final StatusBarPart getLeftPart() {
        return leftPart;
    }

    /**
     * Creates and returns the parts to be added on the right side of the status
     * bar.
     */
    @NotNull
    protected List<StatusBarPart> createRightParts(@NotNull StatusBar statusBar) {
        return Collections.emptyList();
    }

    /**
     * Updates the layout of the status bar parts.
     */
    private void updateLayout() {
        if (rightParts == null)
            return; // right parts are in the process of being created

        FormDataFactory fdf = FormDataFactory.getInstance();
        fdf.margin(0).top().bottom();

        List<StatusBarPart> parts = Lists.reverse(rightParts);
        parts = Util.createList(parts, leftPart);

        Control lastControl = null;
        for (StatusBarPart part : parts) {
            if (!part.isVisible) {
                part.label.setLayoutData(null);
                continue;
            }
            if (lastControl == null)
                fdf.right();
            else
                fdf.right(lastControl, -20);
            fdf.applyTo(part.label);
            lastControl = part.label;
        }

        assert lastControl == leftPart.label;
        fdf.left().applyTo(lastControl);

        layout();
    }

}