ResourceManager.java

package com.swtdesigner;

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>
 * Copyright (c) 2003 - 2007, Instantiations, Inc. <br>
 * All Rights Reserved
 *
 * @author scheglov_ke
 * @author Dan Rubel
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
public class ResourceManager extends SWTResourceManager
{
  // //////////////////////////////////////////////////////////////////////////
  //
  // Image
  //
  // //////////////////////////////////////////////////////////////////////////
  private static Map/* <ImageDescriptor,Image> */ m_descriptorImageMap = new HashMap();

  /**
   * 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 = (Image)m_descriptorImageMap.get(descriptor);
    if (image == null)
    {
      image = descriptor.createImage();
      m_descriptorImageMap.put(descriptor, image);
    }

    return image;
  }

  /**
   * Maps images to decorated images.
   */
  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 cornerDecoratedImageMap = m_decoratedImageMap[corner];
    if (cornerDecoratedImageMap == null)
    {
      cornerDecoratedImageMap = new HashMap();
      m_decoratedImageMap[corner] = cornerDecoratedImageMap;
    }

    Map decoratedMap = (Map)cornerDecoratedImageMap.get(baseImage);
    if (decoratedMap == null)
    {
      decoratedMap = new HashMap();
      cornerDecoratedImageMap.put(baseImage, decoratedMap);
    }

    Image result = (Image)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()
  {
    SWTResourceManager.disposeImages();
    // dispose ImageDescriptor images

    {
      for (Iterator I = m_descriptorImageMap.values().iterator(); I.hasNext();)
      {
        ((Image)I.next()).dispose();
      }

      m_descriptorImageMap.clear();
    }

    // dispose decorated images
    for (int i = 0; i < m_decoratedImageMap.length; i++)
    {
      Map cornerDecoratedImageMap = m_decoratedImageMap[i];
      if (cornerDecoratedImageMap != null)
      {
        for (Iterator I = cornerDecoratedImageMap.values().iterator(); I.hasNext();)
        {
          Map decoratedMap = (Map)I.next();
          for (Iterator J = decoratedMap.values().iterator(); J.hasNext();)
          {
            Image image = (Image)J.next();
            image.dispose();
          }

          decoratedMap.clear();
        }

        cornerDecoratedImageMap.clear();
      }
    }

    // dispose plugin images
    {
      for (Iterator I = m_URLImageMap.values().iterator(); I.hasNext();)
      {
        ((Image)I.next()).dispose();
      }

      m_URLImageMap.clear();
    }
  }

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

  /**
   * 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;

  /**
   * 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
      {
        if (m_URLImageMap.containsKey(url))
        {
          return (Image)m_URLImageMap.get(url);
        }

        InputStream stream = url.openStream();
        Image image;

        try
        {
          image = getImage(stream);
          m_URLImageMap.put(url, 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();
  }
}