org.eclipse.ltk.ui.refactoring/src/org/eclipse/ltk/internal/ui/refactoring/AbstractChangeNode.java

/*******************************************************************************
 * Copyright (c) 2000, 2005 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.ltk.internal.ui.refactoring;

import java.util.List;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;

import org.eclipse.ltk.core.refactoring.Change;
import org.eclipse.ltk.core.refactoring.CompositeChange;
import org.eclipse.ltk.core.refactoring.TextEditBasedChange;

import org.eclipse.jface.resource.ImageDescriptor;

import org.eclipse.ltk.ui.refactoring.ChangePreviewViewerInput;
import org.eclipse.ltk.ui.refactoring.IChangePreviewViewer;
import org.eclipse.ltk.ui.refactoring.TextEditChangeNode;

public abstract class AbstractChangeNode extends PreviewNode {

	private Change fChange;
	private PreviewNode[] fChildren;

	public static PreviewNode createNode(PreviewNode parent, RefactoringPreviewChangeFilter filter, Change change) {
		if (change instanceof CompositeChange) {
			return new CompositeChangeNode(parent, filter, (CompositeChange)change);
		} else if (change instanceof TextEditBasedChange) {
			InternalTextEditChangeNode result= (TextEditChangeNode)change.getAdapter(TextEditChangeNode.class);
			if (result == null) {
				result= new TextEditChangeNode((TextEditBasedChange)change);
			}
			result.initialize(parent);
			return result;
		}
		return new DefaultChangeNode(parent, change);
	}
	
	public static PreviewNode createNode(PreviewNode parent, Change change) {
		return createNode(parent, null, change);
	}
	
	/**
	 * Creates a new <code>AbstractChangeNode</code> for the given
	 * change.
	 * 
	 * @param parent the change nodes's parent or <code>null
	 * 	</code> if the change node doesn't have a parent
	 * @param change the actual change. Argument must not be
	 * 	<code>null</code>
	 */
	AbstractChangeNode(PreviewNode parent, Change change) {
		super(parent);
		Assert.isNotNull(change);
		fChange= change;
	}
	
	/**
	 * Returns the underlying <code>Change</code> object.
	 * 
	 * @return the underlying change
	 */
	Change getChange() {
		return fChange;
	}
	
	PreviewNode[] getChildren() {
		if (fChildren == null) {
			fChildren= doCreateChildren();
		}
		return fChildren;
	}
	
	abstract PreviewNode[] doCreateChildren();
	
	public String getText() {
		return fChange.getName();
	}
	
	public ImageDescriptor getImageDescriptor() {
		return RefactoringPluginImages.DESC_OBJS_DEFAULT_CHANGE;
	}
	
	ChangePreviewViewerDescriptor getChangePreviewViewerDescriptor() throws CoreException {
		return ChangePreviewViewerDescriptor.get(fChange);
	}
	
	void feedInput(IChangePreviewViewer viewer, List categories) throws CoreException {
		viewer.setInput(new ChangePreviewViewerInput(fChange));
	}
	
	void setEnabled(boolean enabled) {
		fChange.setEnabled(enabled);
	}
	
	void setEnabledShallow(boolean enabled) {
		fChange.setEnabledShallow(enabled);
	}
	
	boolean hasOneGroupCategory(List categories) {
		PreviewNode[] children= getChildren();
		for (int i= 0; i < children.length; i++) {
			if (children[i].hasOneGroupCategory(categories))
				return true;
		}
		return false;
	}
	
	int getDefaultChangeActive() {
		int result= fChange.isEnabled() ? ACTIVE : INACTIVE;
		if (fChildren != null) {
			for (int i= 0; i < fChildren.length; i++) {
				result= ACTIVATION_TABLE[fChildren[i].getActive()][result];
				if (result == PARTLY_ACTIVE)
					break;
			}
		}
		return result;
	}
	
	int getCompositeChangeActive() {		
		if (fChildren != null && fChildren.length > 0) {
			int result= fChildren[0].getActive();
			for (int i= 1; i < fChildren.length; i++) {
				result= ACTIVATION_TABLE[fChildren[i].getActive()][result];
				if (result == PARTLY_ACTIVE)
					break;
			}
			return result;
		} else {
			return ACTIVE;
		}
	}
}