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/*
* (C) Copyright 2003-2023, by Barak Naveh 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 org.jgrapht.util.*;
import java.io.*;
import java.util.*;
/**
* A base implementation for the intrusive edges specifics.
*
* @author Barak Naveh
* @author Dimitrios Michail
*
* @param the graph vertex type
* @param the graph edge type
* @param the intrusive edge type
*/
public abstract class BaseIntrusiveEdgesSpecifics
implements Serializable
{
private static final long serialVersionUID = -7498268216742485L;
protected Map edgeMap;
protected transient Set unmodifiableEdgeSet = null;
/**
* Constructor
*
* @param edgeMap the map to use for storage
*/
public BaseIntrusiveEdgesSpecifics(Map edgeMap)
{
this.edgeMap = Objects.requireNonNull(edgeMap);
}
/**
* Check if an edge exists
*
* @param e the edge
* @return true if the edge exists, false otherwise
*/
public boolean containsEdge(E e)
{
return edgeMap.containsKey(e);
}
/**
* Get the edge set.
*
* @return an unmodifiable edge set
*/
public Set getEdgeSet()
{
if (unmodifiableEdgeSet == null) {
unmodifiableEdgeSet = Collections.unmodifiableSet(edgeMap.keySet());
}
return unmodifiableEdgeSet;
}
/**
* Remove an edge.
*
* @param e the edge
*/
public void remove(E e)
{
edgeMap.remove(e);
}
/**
* Get the source of an edge.
*
* @param e the edge
* @return the source vertex of an edge
*/
public V getEdgeSource(E e)
{
IntrusiveEdge ie = getIntrusiveEdge(e);
if (ie == null) {
throw new IllegalArgumentException("no such edge in graph: " + e.toString());
}
return TypeUtil.uncheckedCast(ie.source);
}
/**
* Get the target of an edge.
*
* @param e the edge
* @return the target vertex of an edge
*/
public V getEdgeTarget(E e)
{
IntrusiveEdge ie = getIntrusiveEdge(e);
if (ie == null) {
throw new IllegalArgumentException("no such edge in graph: " + e.toString());
}
return TypeUtil.uncheckedCast(ie.target);
}
/**
* Get the weight of an edge.
*
* @param e the edge
* @return the weight of an edge
*/
public double getEdgeWeight(E e)
{
return Graph.DEFAULT_EDGE_WEIGHT;
}
/**
* Set the weight of an edge
*
* @param e the edge
* @param weight the new weight
*/
public void setEdgeWeight(E e, double weight)
{
throw new UnsupportedOperationException();
}
/**
* Add a new edge
*
* @param e the edge
* @param sourceVertex the source vertex of the edge
* @param targetVertex the target vertex of the edge
* @return true if the edge was added, false if the edge was already present
*/
public abstract boolean add(E e, V sourceVertex, V targetVertex);
protected boolean addIntrusiveEdge(E edge, V sourceVertex, V targetVertex, IE e)
{
if (e.source == null && e.target == null) { // edge not yet in any graph
e.source = sourceVertex;
e.target = targetVertex;
} else if (e.source != sourceVertex || e.target != targetVertex) {
// Edge already contained in this or another graph but with different touching
// edges. Reject the edge to not reset the touching vertices of the edge.
// Changing the touching vertices causes major inconsistent behavior.
throw new IntrusiveEdgeException(e.source, e.target);
}
return edgeMap.putIfAbsent(edge, e) == null;
}
/**
* Get the intrusive edge of an edge.
*
* @param e the edge
* @return the intrusive edge
*/
protected abstract IE getIntrusiveEdge(E e);
}