bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/NavigationHistoryEditorInfo.java

/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal;

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.ui.IEditorInput;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IElementFactory;
import org.eclipse.ui.IMemento;
import org.eclipse.ui.IPersistableElement;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.XMLMemento;
/**
 * Keeps the info to save, restore or identify and editor.
 * Instances of this class are shared between history entries and there should be
 * only one instance making reference to the same editor. 
 */
public class NavigationHistoryEditorInfo {
	String editorID;
	IEditorInput editorInput;
	int refCount = 0;
	IMemento memento;
	
	NavigationHistoryEditorInfo(IEditorPart part) {
		editorID= part.getSite().getId();
		editorInput= part.getEditorInput();
	}
	NavigationHistoryEditorInfo(IMemento memento) {
		this.memento = memento;
	}
	boolean isPersistable() {
		if(editorInput != null) {
			IPersistableElement persistable = editorInput.getPersistable();
			return persistable != null;
		}
		return memento != null;
	}
	void handlePartClosed() {
		if(!isPersistable())
			return;
		if(memento == null) {	
			IPersistableElement persistable = editorInput.getPersistable();	
			memento = XMLMemento.createWriteRoot(IWorkbenchConstants.TAG_EDITOR);
			memento.putString(IWorkbenchConstants.TAG_ID, editorID);
			memento.putString(IWorkbenchConstants.TAG_FACTORY_ID, persistable.getFactoryId());
			persistable.saveState(memento);
		}
		editorID= null;
		editorInput= null;
	}
 	void restoreEditor() {
 		if(memento == null)
 			return;
		String factoryID= memento.getString(IWorkbenchConstants.TAG_FACTORY_ID);
		IElementFactory factory= PlatformUI.getWorkbench().getElementFactory(factoryID);
		if (factory != null) {
			IAdaptable element= factory.createElement(memento);
			if (element instanceof IEditorInput) {
				editorInput= (IEditorInput) element;
				editorID= memento.getString(IWorkbenchConstants.TAG_ID);
			}
		}
		memento = null;
	}	
	void saveState(IMemento mem) {
		if(editorInput != null) {
			IPersistableElement persistable = editorInput.getPersistable(); 
			mem.putString(IWorkbenchConstants.TAG_ID, editorID);
			mem.putString(IWorkbenchConstants.TAG_FACTORY_ID, persistable.getFactoryId());
			persistable.saveState(mem);
		} else if(memento != null) { 
			mem.putMemento(memento);
		}
	}			
}