/*
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*
* The Apache Software License, Version 1.1
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* Copyright (c) 1999-2003 The Apache Software Foundation.
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*
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package org.apache.commons.jrcs.diff.myers;
/**
* A node in a diffpath.
*
* @version $Revision: 7756 $ $Date: 2006-04-12 18:30:19 +0100 (Wed, 12 Apr
* 2006) $
* @author <a href="mailto:juanco@suigeneris.org">Juanco Anez</a>
* @see DiffNode
* @see Snake
*/
public abstract class PathNode
{
/** Position in the original sequence. */
public final int i;
/** Position in the revised sequence. */
public final int j;
/** The previous node in the path. */
public final PathNode prev;
/**
* Concatenates a new path node with an existing diffpath.
*
* @param i
* The position in the original sequence for the new node.
* @param j
* The position in the revised sequence for the new node.
* @param prev
* The previous node in the path.
*/
public PathNode(int i, int j, PathNode prev)
{
this.i = i;
this.j = j;
this.prev = prev;
}
/**
* Is this node a {@link Snake Snake node}?
*
* @return true if this is a {@link Snake Snake node}
*/
public abstract boolean isSnake();
/**
* Is this a bootstrap node?
* <p>
* In bottstrap nodes one of the two corrdinates is less than zero.
*
* @return tru if this is a bootstrap node.
*/
public boolean isBootstrap()
{
return i < 0 || j < 0;
}
/**
* Skips sequences of {@link DiffNode DiffNodes} until a {@link Snake} or
* bootstrap node is found, or the end of the path is reached.
*
* @return The next first {@link Snake} or bootstrap node in the path, or
* <code>null</code> if none found.
*/
public final PathNode previousSnake()
{
if (isBootstrap()) return null;
if (!isSnake() && prev != null) return prev.previousSnake();
return this;
}
/**
* {@inheritDoc}
*/
public String toString()
{
StringBuffer buf = new StringBuffer("[");
PathNode node = this;
while (node != null)
{
buf.append("(");
buf.append(Integer.toString(node.i));
buf.append(",");
buf.append(Integer.toString(node.j));
buf.append(")");
node = node.prev;
}
buf.append("]");
return buf.toString();
}
}