Copyright (c) 2000, 2014 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2014 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.internal.dtree;

This class represents the changes in a single node between two data trees.
/**
 * This class represents the changes in a single node between two data trees.
 */
public final class NodeComparison {
	
The data of the old tree
/**
	 * The data of the old tree
	 */
	private Object oldData;

	
The data of the new tree
/**
	 * The data of the new tree
	 */
	private Object newData;

	
Integer describing changes between two data elements
/**
	 * Integer describing changes between two data elements
	 */
	private int comparison;

	
Extra integer that can be assigned by the client
/**
	 * Extra integer that can be assigned by the client
	 */
	private int userInt;

	
Special bits in the comparison flag to indicate the type of change
/**
	 * Special bits in the comparison flag to indicate the type of change
	 */
	public final static int K_ADDED = 1;
	public final static int K_REMOVED = 2;
	public final static int K_CHANGED = 4;

	NodeComparison(Object oldData, Object newData, int realComparison, int userComparison) {
		this.oldData = oldData;
		this.newData = newData;
		this.comparison = realComparison;
		this.userInt = userComparison;
	}

	
Reverse the nature of the comparison.
/**
	 * Reverse the nature of the comparison.
	 */
	NodeComparison asReverseComparison(IComparator comparator) {
		/* switch the data */
		Object tempData = oldData;
		oldData = newData;
		newData = tempData;

		/* re-calculate user comparison */
		userInt = comparator.compare(oldData, newData);

		if (comparison == K_ADDED) {
			comparison = K_REMOVED;
		} else {
			if (comparison == K_REMOVED) {
				comparison = K_ADDED;
			}
		}
		return this;
	}

	
Returns an integer describing the changes between the two data objects.
The four possible values are K_ADDED, K_REMOVED, K_CHANGED, or 0 representing
no change.
/**
	 * Returns an integer describing the changes between the two data objects.
	 * The four possible values are K_ADDED, K_REMOVED, K_CHANGED, or 0 representing
	 * no change.
	 */
	public int getComparison() {
		return comparison;
	}

	
Returns the data of the new node.
/**
	 * Returns the data of the new node.
	 */
	public Object getNewData() {
		return newData;
	}

	
Returns the data of the old node.
/**
	 * Returns the data of the old node.
	 */
	public Object getOldData() {
		return oldData;
	}

	
Returns the client specified integer
/**
	 * Returns the client specified integer
	 */
	public int getUserComparison() {
		return userInt;
	}

	
Returns true if this comparison has no change, and false otherwise.
/**
	 * Returns true if this comparison has no change, and false otherwise.
	 */
	boolean isUnchanged() {
		return userInt == 0;
	}

	
For debugging
/**
	 * For debugging
	 */
	@Override
	public String toString() {
		StringBuilder buf = new StringBuilder("NodeComparison("); //$NON-NLS-1$
		switch (comparison) {
			case K_ADDED :
				buf.append("Added, "); //$NON-NLS-1$
				break;
			case K_REMOVED :
				buf.append("Removed, "); //$NON-NLS-1$
				break;
			case K_CHANGED :
				buf.append("Changed, "); //$NON-NLS-1$
				break;
			case 0 :
				buf.append("No change, "); //$NON-NLS-1$
				break;
			default :
				buf.append("Corrupt(" + comparison + "), "); //$NON-NLS-1$ //$NON-NLS-2$
		}
		buf.append(userInt);
		buf.append(")"); //$NON-NLS-1$
		return buf.toString();
	}
}