org.eclipse.swt.examples.fileviewer.IconCache.java Source code

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Here is the source code for org.eclipse.swt.examples.fileviewer.IconCache.java

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/*******************************************************************************
 * Copyright (c) 2000, 2015 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.examples.fileviewer;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Cursor;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.program.Program;
import org.eclipse.swt.widgets.Display;

/**
 * Manages icons for the application.
 * This is necessary as we could easily end up creating thousands of icons
 * bearing the same image.
 */
class IconCache {
    // Stock images
    public final int shellIcon = 0, iconClosedDrive = 1, iconClosedFolder = 2, iconFile = 3, iconOpenDrive = 4,
            iconOpenFolder = 5, cmdCopy = 6, cmdCut = 7, cmdDelete = 8, cmdParent = 9, cmdPaste = 10, cmdPrint = 11,
            cmdRefresh = 12, cmdRename = 13, cmdSearch = 14;
    public final String[] stockImageLocations = { "generic_example.gif", "icon_ClosedDrive.gif",
            "icon_ClosedFolder.gif", "icon_File.gif", "icon_OpenDrive.gif", "icon_OpenFolder.gif", "cmd_Copy.gif",
            "cmd_Cut.gif", "cmd_Delete.gif", "cmd_Parent.gif", "cmd_Paste.gif", "cmd_Print.gif", "cmd_Refresh.gif",
            "cmd_Rename.gif", "cmd_Search.gif" };
    public Image stockImages[];

    // Stock cursors
    public final int cursorDefault = 0, cursorWait = 1;
    public Cursor stockCursors[];
    // Cached icons
    private Map<Program, Image> iconCache; /* map Program to Image */

    public IconCache() {
    }

    /**
     * Loads the resources
     *
     * @param display the display
     */
    public void initResources(Display display) {
        if (stockImages == null) {
            stockImages = new Image[stockImageLocations.length];

            for (int i = 0; i < stockImageLocations.length; ++i) {
                Image image = createStockImage(display, stockImageLocations[i]);
                if (image == null) {
                    freeResources();
                    throw new IllegalStateException(FileViewer.getResourceString("error.CouldNotLoadResources"));
                }
                stockImages[i] = image;
            }
        }
        if (stockCursors == null) {
            stockCursors = new Cursor[] { null, display.getSystemCursor(SWT.CURSOR_WAIT) };
        }
        iconCache = new HashMap<>();
    }

    /**
     * Frees the resources
     */
    public void freeResources() {
        if (stockImages != null) {
            for (Image image : stockImages) {
                if (image != null)
                    image.dispose();
            }
            stockImages = null;
        }
        if (iconCache != null) {
            for (Image image : iconCache.values()) {
                image.dispose();
            }
            iconCache = null;
        }
        stockCursors = null;
    }

    /**
     * Creates a stock image
     *
     * @param display the display
     * @param path the relative path to the icon
     */
    private Image createStockImage(Display display, String path) {
        InputStream stream = IconCache.class.getResourceAsStream(path);
        ImageData imageData = new ImageData(stream);
        ImageData mask = imageData.getTransparencyMask();
        Image result = new Image(display, imageData, mask);
        try {
            stream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }

    /**
     * Gets an image for a file associated with a given program
     *
     * @param program the Program
     */
    public Image getIconFromProgram(Program program) {
        Image image = iconCache.get(program);
        if (image == null) {
            ImageData imageData = program.getImageData();
            if (imageData != null) {
                image = new Image(null, imageData, imageData.getTransparencyMask());
                iconCache.put(program, image);
            } else {
                image = stockImages[iconFile];
            }
        }
        return image;
    }
}