001    package org.apache.commons.graph;
002    
003    /*
004     * Licensed to the Apache Software Foundation (ASF) under one
005     * or more contributor license agreements.  See the NOTICE file
006     * distributed with this work for additional information
007     * regarding copyright ownership.  The ASF licenses this file
008     * to you under the Apache License, Version 2.0 (the
009     * "License"); you may not use this file except in compliance
010     * with the License.  You may obtain a copy of the License at
011     *
012     *   http://www.apache.org/licenses/LICENSE-2.0
013     *
014     * Unless required by applicable law or agreed to in writing,
015     * software distributed under the License is distributed on an
016     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017     * KIND, either express or implied.  See the License for the
018     * specific language governing permissions and limitations
019     * under the License.
020     */
021    
022    import java.util.List;
023    
024    /**
025     * A {@code Path} in a {@link Graph} is a sequence of {@link Vertex} such that from each of its vertices there is an
026     * {@link Edge} to the next {@link Vertex} in the sequence.
027     *
028     * @param <V> the Graph vertices type
029     * @param <E> the Graph edges type
030     */
031    public interface Path<V extends Vertex, E extends Edge<V>>
032    {
033    
034        /**
035         * Returns the source of the path.
036         */
037        V getSource();
038    
039        /**
040         * Returns the target of the path.
041         */
042        V getTarget();
043    
044        /**
045         * getVertices() - This returns a list of Vertices, in order as they go from
046         * Start to End. This includes the Start and End vertex, and will have one
047         * more entry than the Edges list.
048         */
049        List<V> getVertices();
050    
051        /**
052         * getEdges() - This returns a list of Edges which comprise the path. It
053         * will have one less than the list of Vertices.
054         */
055        List<E> getEdges();
056    
057        /**
058         * size() - This returns the size of the path in terms of number of
059         * verticies it visits.
060         */
061        int size();
062    
063    }