ExampleResourceManager.java

/*******************************************************************************
 * Copyright (c) 2011 Google, Inc.
 * 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:
 *    Google, Inc. - initial API and implementation
 *******************************************************************************/
package org.eclipse.wb.swt;

import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.resource.CompositeImageDescriptor;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;

import org.osgi.framework.Bundle;

import java.io.File;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/**
 * Utility class for managing OS resources associated with SWT/JFace controls such as colors, fonts, images,
 * etc.
 *
 * !!! IMPORTANT !!! Application code must explicitly invoke the <code>dispose()</code> method to release the
 * operating system resources managed by cached objects when those objects and OS resources are no longer
 * needed (e.g. on application shutdown)
 *
 * This class may be freely distributed as part of any application or plugin.
 * <p>
 *
 * @author scheglov_ke
 * @author Dan Rubel
 */
public class ExampleResourceManager extends ExampleSWTResourceManager
{
  // //////////////////////////////////////////////////////////////////////////
  //
  // Image
  //
  // //////////////////////////////////////////////////////////////////////////
  private static Map<ImageDescriptor, Image> m_descriptorImageMap = new HashMap<ImageDescriptor, Image>();

  /**
   * Returns an {@link ImageDescriptor} stored in the file at the specified path relative to the specified
   * class.
   *
   * @param clazz
   *            the {@link Class} relative to which to find the image descriptor.
   * @param path
   *            the path to the image file.
   * @return the {@link ImageDescriptor} stored in the file at the specified path.
   */
  public static ImageDescriptor getImageDescriptor(Class<?> clazz, String path)
  {
    return ImageDescriptor.createFromFile(clazz, path);
  }

  /**
   * Returns an {@link ImageDescriptor} stored in the file at the specified path.
   *
   * @param path
   *            the path to the image file.
   * @return the {@link ImageDescriptor} stored in the file at the specified path.
   */
  public static ImageDescriptor getImageDescriptor(String path)
  {
    try
    {
      return ImageDescriptor.createFromURL(new File(path).toURI().toURL());
    }
    catch (MalformedURLException e)
    {
      return null;
    }
  }

  /**
   * Returns an {@link Image} based on the specified {@link ImageDescriptor}.
   *
   * @param descriptor
   *            the {@link ImageDescriptor} for the {@link Image}.
   * @return the {@link Image} based on the specified {@link ImageDescriptor}.
   */
  public static Image getImage(ImageDescriptor descriptor)
  {
    if (descriptor == null)
    {
      return null;
    }
    Image image = m_descriptorImageMap.get(descriptor);
    if (image == null)
    {
      image = descriptor.createImage();
      m_descriptorImageMap.put(descriptor, image);
    }
    return image;
  }

  /**
   * Maps images to decorated images.
   */
  @SuppressWarnings("unchecked")
  private static Map<Image, Map<Image, Image>>[] m_decoratedImageMap = new Map[LAST_CORNER_KEY];

  /**
   * Returns an {@link Image} composed of a base image decorated by another image.
   *
   * @param baseImage
   *            the base {@link Image} that should be decorated.
   * @param decorator
   *            the {@link Image} to decorate the base image.
   * @return {@link Image} The resulting decorated image.
   */
  public static Image decorateImage(Image baseImage, Image decorator)
  {
    return decorateImage(baseImage, decorator, BOTTOM_RIGHT);
  }

  /**
   * Returns an {@link Image} composed of a base image decorated by another image.
   *
   * @param baseImage
   *            the base {@link Image} that should be decorated.
   * @param decorator
   *            the {@link Image} to decorate the base image.
   * @param corner
   *            the corner to place decorator image.
   * @return the resulting decorated {@link Image}.
   */
  public static Image decorateImage(final Image baseImage, final Image decorator, final int corner)
  {
    if (corner <= 0 || corner >= LAST_CORNER_KEY)
    {
      throw new IllegalArgumentException("Wrong decorate corner");
    }
    Map<Image, Map<Image, Image>> cornerDecoratedImageMap = m_decoratedImageMap[corner];
    if (cornerDecoratedImageMap == null)
    {
      cornerDecoratedImageMap = new HashMap<Image, Map<Image, Image>>();
      m_decoratedImageMap[corner] = cornerDecoratedImageMap;
    }
    Map<Image, Image> decoratedMap = cornerDecoratedImageMap.get(baseImage);
    if (decoratedMap == null)
    {
      decoratedMap = new HashMap<Image, Image>();
      cornerDecoratedImageMap.put(baseImage, decoratedMap);
    }
    //
    Image result = decoratedMap.get(decorator);
    if (result == null)
    {
      final Rectangle bib = baseImage.getBounds();
      final Rectangle dib = decorator.getBounds();
      final Point baseImageSize = new Point(bib.width, bib.height);
      CompositeImageDescriptor compositImageDesc = new CompositeImageDescriptor()
      {
        @Override
        protected void drawCompositeImage(int width, int height)
        {
          drawImage(baseImage.getImageData(), 0, 0);
          if (corner == TOP_LEFT)
          {
            drawImage(decorator.getImageData(), 0, 0);
          }
          else if (corner == TOP_RIGHT)
          {
            drawImage(decorator.getImageData(), bib.width - dib.width, 0);
          }
          else if (corner == BOTTOM_LEFT)
          {
            drawImage(decorator.getImageData(), 0, bib.height - dib.height);
          }
          else if (corner == BOTTOM_RIGHT)
          {
            drawImage(decorator.getImageData(), bib.width - dib.width, bib.height - dib.height);
          }
        }

        @Override
        protected Point getSize()
        {
          return baseImageSize;
        }
      };
      //
      result = compositImageDesc.createImage();
      decoratedMap.put(decorator, result);
    }
    return result;
  }

  /**
   * Dispose all of the cached images.
   */
  public static void disposeImages()
  {
    ExampleSWTResourceManager.disposeImages();
    // dispose ImageDescriptor images
    {
      for (Iterator<Image> I = m_descriptorImageMap.values().iterator(); I.hasNext();)
      {
        I.next().dispose();
      }
      m_descriptorImageMap.clear();
    }
    // dispose decorated images
    for (int i = 0; i < m_decoratedImageMap.length; i++)
    {
      Map<Image, Map<Image, Image>> cornerDecoratedImageMap = m_decoratedImageMap[i];
      if (cornerDecoratedImageMap != null)
      {
        for (Map<Image, Image> decoratedMap : cornerDecoratedImageMap.values())
        {
          for (Image image : decoratedMap.values())
          {
            image.dispose();
          }
          decoratedMap.clear();
        }
        cornerDecoratedImageMap.clear();
      }
    }
    // dispose plugin images
    {
      for (Iterator<Image> I = m_URLImageMap.values().iterator(); I.hasNext();)
      {
        I.next().dispose();
      }
      m_URLImageMap.clear();
    }
  }

  // //////////////////////////////////////////////////////////////////////////
  //
  // Plugin images support
  //
  // //////////////////////////////////////////////////////////////////////////
  /**
   * Maps URL to images.
   */
  private static Map<String, Image> m_URLImageMap = new HashMap<String, Image>();

  /**
   * Provider for plugin resources, used by WindowBuilder at design time.
   */
  public interface PluginResourceProvider
  {
    URL getEntry(String symbolicName, String path);
  }

  /**
   * Instance of {@link PluginResourceProvider}, used by WindowBuilder at design time.
   */
  private static PluginResourceProvider m_designTimePluginResourceProvider = null;

  /**
   * Returns an {@link Image} based on a plugin and file path.
   *
   * @param plugin
   *            the plugin {@link Object} containing the image
   * @param name
   *            the path to the image within the plugin
   * @return the {@link Image} stored in the file at the specified path
   *
   * @deprecated Use {@link #getPluginImage(String, String)} instead.
   */
  @Deprecated
  public static Image getPluginImage(Object plugin, String name)
  {
    try
    {
      URL url = getPluginImageURL(plugin, name);
      if (url != null)
      {
        return getPluginImageFromUrl(url);
      }
    }
    catch (Throwable e)
    {
      // Ignore any exceptions
    }
    return null;
  }

  /**
   * Returns an {@link Image} based on a {@link Bundle} and resource entry path.
   *
   * @param symbolicName
   *            the symbolic name of the {@link Bundle}.
   * @param path
   *            the path of the resource entry.
   * @return the {@link Image} stored in the file at the specified path.
   */
  public static Image getPluginImage(String symbolicName, String path)
  {
    try
    {
      URL url = getPluginImageURL(symbolicName, path);
      if (url != null)
      {
        return getPluginImageFromUrl(url);
      }
    }
    catch (Throwable e)
    {
      // Ignore any exceptions
    }
    return null;
  }

  /**
   * Returns an {@link Image} based on given {@link URL}.
   */
  private static Image getPluginImageFromUrl(URL url)
  {
    try
    {
      try
      {
        String key = url.toExternalForm();
        Image image = m_URLImageMap.get(key);
        if (image == null)
        {
          InputStream stream = url.openStream();
          try
          {
            image = getImage(stream);
            m_URLImageMap.put(key, image);
          }
          finally
          {
            stream.close();
          }
        }
        return image;
      }
      catch (Throwable e)
      {
        // Ignore any exceptions
      }
    }
    catch (Throwable e)
    {
      // Ignore any exceptions
    }
    return null;
  }

  /**
   * Returns an {@link ImageDescriptor} based on a plugin and file path.
   *
   * @param plugin
   *            the plugin {@link Object} containing the image.
   * @param name
   *            the path to th eimage within the plugin.
   * @return the {@link ImageDescriptor} stored in the file at the specified path.
   *
   * @deprecated Use {@link #getPluginImageDescriptor(String, String)} instead.
   */
  @Deprecated
  public static ImageDescriptor getPluginImageDescriptor(Object plugin, String name)
  {
    try
    {
      try
      {
        URL url = getPluginImageURL(plugin, name);
        return ImageDescriptor.createFromURL(url);
      }
      catch (Throwable e)
      {
        // Ignore any exceptions
      }
    }
    catch (Throwable e)
    {
      // Ignore any exceptions
    }
    return null;
  }

  /**
   * Returns an {@link ImageDescriptor} based on a {@link Bundle} and resource entry path.
   *
   * @param symbolicName
   *            the symbolic name of the {@link Bundle}.
   * @param path
   *            the path of the resource entry.
   * @return the {@link ImageDescriptor} based on a {@link Bundle} and resource entry path.
   */
  public static ImageDescriptor getPluginImageDescriptor(String symbolicName, String path)
  {
    try
    {
      URL url = getPluginImageURL(symbolicName, path);
      if (url != null)
      {
        return ImageDescriptor.createFromURL(url);
      }
    }
    catch (Throwable e)
    {
      // Ignore any exceptions
    }
    return null;
  }

  /**
   * Returns an {@link URL} based on a {@link Bundle} and resource entry path.
   */
  private static URL getPluginImageURL(String symbolicName, String path)
  {
    // try runtime plugins
    {
      Bundle bundle = Platform.getBundle(symbolicName);
      if (bundle != null)
      {
        return bundle.getEntry(path);
      }
    }
    // try design time provider
    if (m_designTimePluginResourceProvider != null)
    {
      return m_designTimePluginResourceProvider.getEntry(symbolicName, path);
    }
    // no such resource
    return null;
  }

  /**
   * Returns an {@link URL} based on a plugin and file path.
   *
   * @param plugin
   *            the plugin {@link Object} containing the file path.
   * @param name
   *            the file path.
   * @return the {@link URL} representing the file at the specified path.
   * @throws Exception
   */
  private static URL getPluginImageURL(Object plugin, String name) throws Exception
  {
    // try to work with 'plugin' as with OSGI BundleContext
    try
    {
      Class<?> BundleClass = Class.forName("org.osgi.framework.Bundle"); //$NON-NLS-1$
      Class<?> BundleContextClass = Class.forName("org.osgi.framework.BundleContext"); //$NON-NLS-1$
      if (BundleContextClass.isAssignableFrom(plugin.getClass()))
      {
        Method getBundleMethod = BundleContextClass.getMethod("getBundle", new Class[0]); //$NON-NLS-1$
        Object bundle = getBundleMethod.invoke(plugin, new Object[0]);
        //
        Class<?> PathClass = Class.forName("org.eclipse.core.runtime.Path"); //$NON-NLS-1$
        Constructor<?> pathConstructor = PathClass.getConstructor(new Class[] { String.class });
        Object path = pathConstructor.newInstance(new Object[] { name });
        //
        Class<?> IPathClass = Class.forName("org.eclipse.core.runtime.IPath"); //$NON-NLS-1$
        Class<?> PlatformClass = Class.forName("org.eclipse.core.runtime.Platform"); //$NON-NLS-1$
        Method findMethod = PlatformClass.getMethod("find", new Class[] { BundleClass, IPathClass }); //$NON-NLS-1$
        return (URL)findMethod.invoke(null, new Object[] { bundle, path });
      }
    }
    catch (Throwable e)
    {
      // Ignore any exceptions
    }
    // else work with 'plugin' as with usual Eclipse plugin
    {
      Class<?> PluginClass = Class.forName("org.eclipse.core.runtime.Plugin"); //$NON-NLS-1$
      if (PluginClass.isAssignableFrom(plugin.getClass()))
      {
        //
        Class<?> PathClass = Class.forName("org.eclipse.core.runtime.Path"); //$NON-NLS-1$
        Constructor<?> pathConstructor = PathClass.getConstructor(new Class[] { String.class });
        Object path = pathConstructor.newInstance(new Object[] { name });
        //
        Class<?> IPathClass = Class.forName("org.eclipse.core.runtime.IPath"); //$NON-NLS-1$
        Method findMethod = PluginClass.getMethod("find", new Class[] { IPathClass }); //$NON-NLS-1$
        return (URL)findMethod.invoke(plugin, new Object[] { path });
      }
    }
    return null;
  }

  // //////////////////////////////////////////////////////////////////////////
  //
  // General
  //
  // //////////////////////////////////////////////////////////////////////////
  /**
   * Dispose of cached objects and their underlying OS resources. This should only be called when the cached
   * objects are no longer needed (e.g. on application shutdown).
   */
  public static void dispose()
  {
    disposeColors();
    disposeFonts();
    disposeImages();
  }
}