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/* ==========================================
* JGraphT : a free Java graph-theory library
* ==========================================
*
* Project Info: http://jgrapht.sourceforge.net/
* Project Creator: Barak Naveh (http://sourceforge.net/users/barak_naveh)
*
* (C) Copyright 2003-2007, by Barak Naveh and Contributors.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
*/
/* -----------------
* EquivalenceComparatorChainBase.java
* -----------------
* (C) Copyright 2005-2007, by Assaf Lehr and Contributors.
*
* Original Author: Assaf Lehr
* Contributor(s): -
*
* $Id: EquivalenceComparatorChainBase.java 485 2006-06-26 09:12:14Z perfecthash
* $
*
* Changes
* -------
*/
package org.jgrapht.experimental.equivalence;
import java.util.*;
/**
* This class implements comparator chaining.
*
* Usage examples:
*
graph-theory, node equivalence: You can create a comparator for
* the inDegree of a node, another for the total weight of outDegree edges, and
* a third which checks the business content of the node. You know that the
* first topological comparators has dozens of different groups, but the
* buisness comparator has only two, and they are hard to check . The best
* performance will be gained by:
*
*
* EquivalenceComparatorChainBase eqChain = new
* EquivalenceComparatorChainBase(fastNodesDegreeComparator);
*
*
eqChain.addComparatorAfter(ABitSlowerEdgeWeightComparator);
*
*
eqChain.addComparatorAfter(slowestBuisnessContentsComparator);
*
*
* @param the type of the elements in the set
* @param the type of the context the element is compared against, e.g. a
* Graph
*
* @author Assaf
* @since Jul 22, 2005
*/
public class EquivalenceComparatorChainBase
implements EquivalenceComparatorChain
{
//~ Instance fields --------------------------------------------------------
private List> chain;
//~ Constructors -----------------------------------------------------------
/**
*/
public EquivalenceComparatorChainBase(
EquivalenceComparator firstComaparator)
{
this.chain =
new LinkedList>();
this.chain.add(firstComaparator);
}
//~ Methods ----------------------------------------------------------------
/* (non-Javadoc)
* @see
*
*
*
*
*
* org.jgrapht.experimental.equivalence.EquivalenceComparatorChain#addComparatorAfter(org.jgrapht.experimental.equivalence.EquivalenceComparator)
*/
@SuppressWarnings("unchecked")
public void appendComparator(EquivalenceComparator comparatorAfter)
{
if (comparatorAfter != null) {
this.chain.add(comparatorAfter);
}
}
/**
* Implements logical AND between the comparators results. Iterates through
* the comparators chain until one of them returns false. If none returns
* false, this method returns true.
*
* @see EquivalenceComparator#equivalenceCompare(Object, Object, Object,
* Object)
*/
public boolean equivalenceCompare(
E arg1,
E arg2,
C context1,
C context2)
{
for (
EquivalenceComparator currentComparator
: this.chain)
{
if (!currentComparator.equivalenceCompare(
arg1,
arg2,
context1,
context2))
{
return false;
}
}
return true;
}
/**
* Rehashes the concatenation of the results of all single hashcodes.
*
* @see EquivalenceComparator#equivalenceHashcode(Object, Object)
*/
public int equivalenceHashcode(E arg1, C context)
{
StringBuffer hashStringBuffer = new StringBuffer();
for (
ListIterator> iter =
this.chain.listIterator();
iter.hasNext();)
{
EquivalenceComparator currentComparator =
iter.next();
int currentHashCode =
currentComparator.equivalenceHashcode(arg1, context);
hashStringBuffer.append(currentHashCode);
// add a delimeter only if needed for next
if (iter.hasNext()) {
hashStringBuffer.append('+');
}
}
return hashStringBuffer.toString().hashCode();
}
}
// End EquivalenceComparatorChainBase.java