org.jgrapht.graph.ParanoidGraph Maven / Gradle / Ivy
/*
* (C) Copyright 2007-2020, by John V Sichi and Contributors.
*
* JGraphT : a free Java graph-theory library
*
* See the CONTRIBUTORS.md file distributed with this work for additional
* information regarding copyright ownership.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0, or the
* GNU Lesser General Public License v2.1 or later
* which is available at
* http://www.gnu.org/licenses/old-licenses/lgpl-2.1-standalone.html.
*
* SPDX-License-Identifier: EPL-2.0 OR LGPL-2.1-or-later
*/
package org.jgrapht.graph;
import org.jgrapht.*;
import java.util.*;
/**
* ParanoidGraph provides a way to verify that objects added to a graph obey the standard
* equals/hashCode contract. It can be used to wrap an underlying graph to be verified. Note that
* the verification is very expensive, so ParanoidGraph should only be used during debugging.
*
* @param the graph vertex type
* @param the graph edge type
*
* @author John Sichi
*/
public class ParanoidGraph
extends
GraphDelegator
{
private static final long serialVersionUID = 5075284167422166539L;
/**
* Create a new paranoid graph.
*
* @param g the underlying wrapped graph
*/
public ParanoidGraph(Graph g)
{
super(g);
}
/**
* {@inheritDoc}
*/
@Override
public boolean addEdge(V sourceVertex, V targetVertex, E e)
{
verifyAdd(edgeSet(), e);
return super.addEdge(sourceVertex, targetVertex, e);
}
/**
* {@inheritDoc}
*/
@Override
public boolean addVertex(V v)
{
verifyAdd(vertexSet(), v);
return super.addVertex(v);
}
private static void verifyAdd(Set set, T t)
{
for (T o : set) {
if (o == t) {
continue;
}
if (o.equals(t) && (o.hashCode() != t.hashCode())) {
throw new IllegalArgumentException(
"ParanoidGraph detected objects " + "o1 (hashCode=" + o.hashCode()
+ ") and o2 (hashCode=" + t.hashCode() + ") where o1.equals(o2) "
+ "but o1.hashCode() != o2.hashCode()");
}
}
}
}