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/*
* (C) Copyright 2017-2023, by Dimitrios Michail 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 java.io.*;
import java.util.*;
import java.util.function.*;
/**
* Default implementation of an edge function which uses a map to store values.
*
* @author Dimitrios Michail
*
* @param the edge type
* @param the value type
*/
public class DefaultEdgeFunction
implements Function, Serializable
{
private static final long serialVersionUID = -4247429315268336855L;
protected final Map map;
protected final T defaultValue;
/**
* Create a new function
*
* @param defaultValue the default value
*/
public DefaultEdgeFunction(T defaultValue)
{
this(defaultValue, new HashMap<>());
}
/**
* Create a new function
*
* @param defaultValue the default value
* @param map the underlying map
*/
public DefaultEdgeFunction(T defaultValue, Map map)
{
this.defaultValue = Objects.requireNonNull(defaultValue, "Default value cannot be null");
this.map = Objects.requireNonNull(map, "Map cannot be null");
}
/**
* Get the function value for an edge.
*
* @param e the edge
*/
@Override
public T apply(E e)
{
return map.getOrDefault(e, defaultValue);
}
/**
* Get the function value for an edge.
*
* @param e the edge
* @return the function value for the edge
*/
public T get(E e)
{
return map.getOrDefault(e, defaultValue);
}
/**
* Set the function value for an edge.
*
* @param e the edge
* @param value the value
*/
public void set(E e, T value)
{
map.put(e, value);
}
}