001/* Computation of source nodes in a graph.
002
003 Copyright (c) 2002-2014 The University of Maryland. All rights reserved.
004 Permission is hereby granted, without written agreement and without
005 license or royalty fees, to use, copy, modify, and distribute this
006 software and its documentation for any purpose, provided that the above
007 copyright notice and the following two paragraphs appear in all copies
008 of this software.
009
010 IN NO EVENT SHALL THE UNIVERSITY OF MARYLAND BE LIABLE TO ANY PARTY
011 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
012 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
013 THE UNIVERSITY OF MARYLAND HAS BEEN ADVISED OF THE POSSIBILITY OF
014 SUCH DAMAGE.
015
016 THE UNIVERSITY OF MARYLAND SPECIFICALLY DISCLAIMS ANY WARRANTIES,
017 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
018 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
019 PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
020 MARYLAND HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
021 ENHANCEMENTS, OR MODIFICATIONS.
022
023
024 */
025package ptolemy.graph.analysis;
026
027import java.util.List;
028
029import ptolemy.graph.Graph;
030import ptolemy.graph.analysis.analyzer.Analyzer;
031import ptolemy.graph.analysis.analyzer.SourceNodeAnalyzer;
032import ptolemy.graph.analysis.strategy.SourceNodeStrategy;
033
034///////////////////////////////////////////////////////////////////
035//// SourceNodeAnalysis
036
037/**
038 Computation of source nodes in a graph.
039 A source node in a graph is a node without input edges.
040 <p>
041 The returned collection cannot be modified when the client uses the default
042 analyzer.
043 <p>
044 @since Ptolemy II 2.0
045 @Pt.ProposedRating Red (shahrooz)
046 @Pt.AcceptedRating Red (ssb)
047 @author Shahrooz Shahparnia
048 @version $Id$
049 */
050public class SourceNodeAnalysis extends Analysis {
051    /** Construct an instance of this class for a given graph.
052     *
053     *  @param graph The given graph.
054     */
055    public SourceNodeAnalysis(Graph graph) {
056        super(new SourceNodeStrategy(graph));
057    }
058
059    /** Construct an instance of this class using a given analyzer.
060     *
061     *  @param analyzer The given analyzer.
062     */
063    public SourceNodeAnalysis(SourceNodeAnalyzer analyzer) {
064        super(analyzer);
065    }
066
067    ///////////////////////////////////////////////////////////////////
068    ////                         public methods                    ////
069
070    /** Return the source nodes in the graph under analysis.
071     *  Each element of the collection is an {@link ptolemy.graph.Node}.
072     *
073     *  @return Return the source nodes.
074     */
075    public List nodes() {
076        return ((SourceNodeAnalyzer) analyzer()).nodes();
077    }
078
079    /** Return a description of the analysis and the associated analyzer.
080     *
081     *  @return A description of the analysis and the associated analyzer.
082     */
083    @Override
084    public String toString() {
085        return "Source node analysis using the following analyzer:\n"
086                + analyzer().toString();
087    }
088
089    /** Check if a given analyzer is compatible with this analysis.
090     *  In other words if it is possible to use it to compute the computation
091     *  associated with this analysis.
092     *
093     *  @param analyzer The given analyzer.
094     *  @return True if the given analyzer is valid for this analysis.
095     */
096    @Override
097    public boolean validAnalyzerInterface(Analyzer analyzer) {
098        return analyzer instanceof SourceNodeAnalyzer;
099    }
100}