| /* |
| * (c) Copyright IBM Corp. 2000, 2001. |
| * All Rights Reserved. |
| */ |
| package org.eclipse.compare.internal; |
| |
| import org.eclipse.swt.widgets.Composite; |
| |
| import org.eclipse.core.runtime.CoreException; |
| import org.eclipse.core.runtime.IConfigurationElement; |
| import org.eclipse.compare.*; |
| |
| import org.eclipse.jface.viewers.Viewer; |
| |
| /** |
| * Creates <code>Viewer</code>s from an <code>IConfigurationElement</code>. |
| */ |
| public class ViewerDescriptor implements IViewerDescriptor { |
| |
| private final static String CLASS_ATTRIBUTE= "class"; //$NON-NLS-1$ |
| private final static String EXTENSIONS_ATTRIBUTE= "extensions"; //$NON-NLS-1$ |
| |
| private IConfigurationElement fConfiguration; |
| private IViewerCreator fViewerCreator; |
| private Class fViewerClass; |
| |
| public ViewerDescriptor(IConfigurationElement config) { |
| fConfiguration= config; |
| } |
| |
| public Viewer createViewer(Viewer currentViewer, Composite parent, CompareConfiguration mp) { |
| |
| if (currentViewer != null && currentViewer.getClass() == fViewerClass) { |
| //System.out.println("reused viewer: " + currentViewer.getClass().getName()); |
| return currentViewer; |
| } |
| |
| if (fViewerCreator == null) { |
| try { |
| fViewerCreator= (IViewerCreator) fConfiguration.createExecutableExtension(CLASS_ATTRIBUTE); |
| } catch (CoreException e) { |
| } |
| } |
| |
| if (fViewerCreator != null) { |
| Viewer viewer= fViewerCreator.createViewer(parent, mp); |
| if (viewer != null) |
| fViewerClass= viewer.getClass(); |
| return viewer; |
| } |
| |
| return null; |
| } |
| |
| public String getExtension() { |
| return fConfiguration.getAttribute(EXTENSIONS_ATTRIBUTE); |
| } |
| } |