/*******************************************************************************
* Copyright (c) 2005, 2015 IBM Corporation and others.
* 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.ui.internal.util;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.eclipse.jface.resource.ColorDescriptor;
import org.eclipse.jface.resource.DeviceResourceDescriptor;
import org.eclipse.jface.resource.DeviceResourceException;
import org.eclipse.jface.resource.FontDescriptor;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.resource.ResourceManager;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Item;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.TableItem;
import org.eclipse.swt.widgets.ToolItem;
import org.eclipse.swt.widgets.Widget;
import org.eclipse.ui.internal.WorkbenchPlugin;
/**
* Contains a bunch of helper methods that allow JFace resource descriptors to be passed
* directly to SWT widgets without worrying about resource allocation. This class is internal,
* but it should be moved into JFace if the pattern is found generally useful. The current
* implementation uses a lot of reflection to save repeated code, but this could all be inlined
* (without reflection) if performance turns out to be a problem.
*
* <p>
* For example, an Image might be passed to a TableItem as follows:
* <p>
*
* <code>
* ImageDescriptor someDescriptor = ...;
* TableItem someTableItem = ...;
* ResourceManager manager = JFaceResources.getResources();
*
* Image actualImage = manager.createImage(someDescriptor);
* someTableItem.setImage(actualImage);
*
* // do something with the table item
*
* someTableItem.dispose();
* manager.destroyImage(someDescriptor);
* </code>
*
* <p>
* It is much more convenient to do the following:
* </p>
*
* <code>
* ImageDescriptor someDescriptor = ...;
* TableItem someTableItem = ...;
*
* Descriptors.setImage(someTableItem, someDescriptor);
*
* // do something with the table item
*
* someTableItem.dispose();
* </code>
*
* <p>
* This class tries to behave as if the table item itself had a set method that took a descriptor.
* Resource allocation and deallocation happens for free. All the methods are leakproof. That is,
* if any images, colors, etc. need to be allocated and passed to the SWT widget, they will be
* deallocated automatically when the widget goes away (the implementation hooks a dispose listener
* on the widget which cleans up as soon as the widget is disposed).
* </p>
*
* @since 3.1
*/
public final class Descriptors {
private static final String DISPOSE_LIST = "Descriptors.disposeList"; //$NON-NLS-1$
private Descriptors() {
}
private static final class ResourceMethod {
ResourceMethod(Method m, String id) {
method = m;
this.id = id;
}
Method method;
DeviceResourceDescriptor oldDescriptor;
String id;
public void invoke(Widget toCall, DeviceResourceDescriptor newDescriptor) {
if (newDescriptor == oldDescriptor) {
return;
}
ResourceManager mgr = JFaceResources.getResources(toCall.getDisplay());
Object newResource;
try {
newResource = newDescriptor == null? null : mgr.create(newDescriptor);
} catch (DeviceResourceException e1) {
WorkbenchPlugin.log(e1);
return;
}
try {
method.invoke(toCall, new Object[] {newResource});
} catch (IllegalArgumentException e) {
throw e;
} catch (IllegalAccessException e) {
WorkbenchPlugin.log(e);
return;
} catch (InvocationTargetException e) {
if (e.getTargetException() instanceof RuntimeException) {
throw (RuntimeException)e.getTargetException();
}
WorkbenchPlugin.log(e);
return;
}
// Deallocate the old image
if (oldDescriptor != null) {
// Dispose the image
mgr.destroy(oldDescriptor);
}
// Remember the new image for next time
oldDescriptor = newDescriptor;
}
public void dispose() {
// Deallocate the old image
if (oldDescriptor != null) {
ResourceManager mgr = JFaceResources.getResources();
// Dispose the image
mgr.destroy(oldDescriptor);
oldDescriptor = null;
}
}
}
private static DisposeListener disposeListener = e -> doDispose(e.widget);
// Item //////////////////////////////////////////////////////////////////////////////////
/**
* Sets the image on the given ToolItem. The image will be automatically allocated and
* disposed as needed.
*
* @since 3.1
*
* @param item
* @param descriptor
*/
public static void setImage(Item item, ImageDescriptor descriptor) {
callMethod(item, "setImage", descriptor, Image.class); //$NON-NLS-1$
}
// ToolItem //////////////////////////////////////////////////////////////////////////////
public static void setHotImage(ToolItem item, ImageDescriptor descriptor) {
callMethod(item, "setHotImage", descriptor, Image.class); //$NON-NLS-1$
}
public static void setDisabledImage(ToolItem item, ImageDescriptor descriptor) {
callMethod(item, "setDisabledImage", descriptor, Image.class); //$NON-NLS-1$
}
// TableItem //////////////////////////////////////////////////////////////////////////////
public static void setFont(TableItem item, FontDescriptor descriptor) {
callMethod(item, "setFont", descriptor, Font.class); //$NON-NLS-1$
}
public static void setBackground(TableItem item, ColorDescriptor descriptor) {
callMethod(item, "setBackground", descriptor, Color.class); //$NON-NLS-1$
}
public static void setForeground(TableItem item, ColorDescriptor descriptor) {
callMethod(item, "setForeground", descriptor, Color.class); //$NON-NLS-1$
}
// Control ///////////////////////////////////////////////////////////////////////////////
public static void setBackground(Control control, ColorDescriptor descriptor) {
callMethod(control, "setBackground", descriptor, Color.class); //$NON-NLS-1$
}
public static void setForeground(Control control, ColorDescriptor descriptor) {
callMethod(control, "setForeground", descriptor, Color.class); //$NON-NLS-1$
}
// Button ///////////////////////////////////////////////////////////////////////////////
public static void setImage(Button button, ImageDescriptor descriptor) {
callMethod(button, "setImage", descriptor, Image.class); //$NON-NLS-1$
}
public static void setImage(Label label, ImageDescriptor descriptor) {
callMethod(label, "setImage", descriptor, Image.class); //$NON-NLS-1$
}
private static ResourceMethod getResourceMethod(Widget toCall, String methodName, Class resourceType) throws NoSuchMethodException {
Object oldData = toCall.getData(DISPOSE_LIST);
if (oldData instanceof List) {
// Check for existing data
for (Iterator iter = ((List)oldData).iterator(); iter.hasNext();) {
ResourceMethod method = (ResourceMethod) iter.next();
if (method.id == methodName) {
return method;
}
}
} if (oldData instanceof ResourceMethod) {
if (((ResourceMethod)oldData).id == methodName) {
return ((ResourceMethod)oldData);
}
List newList = new ArrayList();
newList.add(oldData);
oldData = newList;
toCall.setData(DISPOSE_LIST, oldData);
}
// At this point, the DISPOSE_LIST data is either null or points to an ArrayList
Class clazz = toCall.getClass();
Method method;
try {
method = clazz.getMethod(methodName, new Class[] {resourceType});
} catch (SecurityException e) {
throw e;
}
ResourceMethod result = new ResourceMethod(method, methodName);
if (oldData == null) {
toCall.setData(DISPOSE_LIST, result);
toCall.addDisposeListener(disposeListener);
} else {
((List)oldData).add(result);
}
return result;
}
private static void callMethod(Widget toCall, String methodName, DeviceResourceDescriptor descriptor, Class resourceType) {
ResourceMethod method;
try {
method = getResourceMethod(toCall, methodName, resourceType);
} catch (NoSuchMethodException e) {
WorkbenchPlugin.log(e);
return;
}
method.invoke(toCall, descriptor);
}
private static void doDispose(Widget widget) {
Object oldData = widget.getData(DISPOSE_LIST);
if (oldData instanceof ArrayList) {
ArrayList list = ((ArrayList)oldData);
ResourceMethod[] data = (ResourceMethod[]) list.toArray(new ResourceMethod[list.size()]);
// Clear out the images
for (ResourceMethod method : data) {
method.dispose();
}
}
if (oldData instanceof ResourceMethod) {
((ResourceMethod)oldData).dispose();
}
}
}