[13] | 1 | package de.ugoe.cs.eventbench.models;
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[1] | 2 |
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[9] | 3 | import java.util.LinkedHashSet;
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[1] | 4 | import java.util.LinkedList;
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| 5 | import java.util.List;
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[9] | 6 | import java.util.Set;
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[1] | 7 |
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[30] | 8 | import de.ugoe.cs.util.StringTools;
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| 9 |
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[5] | 10 | import edu.uci.ics.jung.graph.DelegateTree;
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| 11 | import edu.uci.ics.jung.graph.Tree;
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| 12 |
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[30] | 13 | public class Trie<T> implements IDotCompatible {
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[1] | 14 |
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[9] | 15 | private Set<T> knownSymbols;
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| 16 |
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[6] | 17 | private final TrieNode<T> rootNode;
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[1] | 18 |
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[6] | 19 | public Trie() {
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| 20 | rootNode = new TrieNode<T>();
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[9] | 21 | knownSymbols = new LinkedHashSet<T>();
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[6] | 22 | }
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| 23 |
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[9] | 24 | public Set<T> getKnownSymbols() {
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| 25 | return new LinkedHashSet<T>(knownSymbols);
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| 26 | }
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| 27 |
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[16] | 28 | // trains the current Trie using the given sequence and adds all subsequence of length trieOrder
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[9] | 29 | public void train(List<T> sequence, int maxOrder) {
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| 30 | IncompleteMemory<T> latestActions = new IncompleteMemory<T>(maxOrder);
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| 31 | int i=0;
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| 32 | for(T currentEvent : sequence) {
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| 33 | latestActions.add(currentEvent);
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| 34 | knownSymbols.add(currentEvent);
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| 35 | i++;
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| 36 | if( i>=maxOrder ) {
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| 37 | add(latestActions.getLast(maxOrder));
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| 38 | }
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| 39 | }
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| 40 | int sequenceLength = sequence.size();
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| 41 | for( int j=maxOrder-1 ; j>0 ; j-- ) {
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| 42 | add(sequence.subList(sequenceLength-j, sequenceLength));
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| 43 | }
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| 44 | }
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| 45 |
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[1] | 46 |
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[9] | 47 | // increases the counters for each symbol in the subsequence
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[1] | 48 | public void add(List<T> subsequence) {
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[9] | 49 | if( subsequence!=null && !subsequence.isEmpty() ) {
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| 50 | knownSymbols.addAll(subsequence);
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[5] | 51 | subsequence = new LinkedList<T>(subsequence); // defensive copy!
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[1] | 52 | T firstSymbol = subsequence.get(0);
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[6] | 53 | TrieNode<T> node = getChildCreate(firstSymbol);
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| 54 | node.add(subsequence);
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[1] | 55 | }
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| 56 | }
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| 57 |
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| 58 | protected TrieNode<T> getChildCreate(T symbol) {
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[6] | 59 | return rootNode.getChildCreate(symbol);
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[1] | 60 | }
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| 61 |
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| 62 | protected TrieNode<T> getChild(T symbol) {
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[6] | 63 | return rootNode.getChild(symbol);
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[1] | 64 | }
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| 65 |
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[5] | 66 | // get the count of "sequence"
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[1] | 67 | public int getCount(List<T> sequence) {
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| 68 | int count = 0;
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| 69 | TrieNode<T> node = find(sequence);
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| 70 | if( node!=null ) {
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| 71 | count = node.getCount();
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| 72 | }
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| 73 | return count;
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| 74 | }
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| 75 |
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[5] | 76 | // get the count of "sequence,follower"
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[1] | 77 | public int getCount(List<T> sequence, T follower) {
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| 78 | List<T> tmpSequence = new LinkedList<T>(sequence);
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| 79 | tmpSequence.add(follower);
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| 80 | return getCount(tmpSequence);
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| 81 |
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| 82 | }
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| 83 |
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| 84 | public TrieNode<T> find(List<T> sequence) {
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[6] | 85 | if( sequence==null || sequence.isEmpty() ) {
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| 86 | return rootNode;
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| 87 | }
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[5] | 88 | List<T> sequenceCopy = new LinkedList<T>(sequence);
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[1] | 89 | TrieNode<T> result = null;
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[6] | 90 | TrieNode<T> node = getChild(sequenceCopy.get(0));
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| 91 | if( node!=null ) {
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| 92 | sequenceCopy.remove(0);
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| 93 | result = node.find(sequenceCopy);
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[1] | 94 | }
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| 95 | return result;
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| 96 | }
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| 97 |
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[5] | 98 | // returns all symbols that follow the defined sequence
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[1] | 99 | public List<T> getFollowingSymbols(List<T> sequence) {
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[5] | 100 | List<T> result = new LinkedList<T>();
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[6] | 101 | TrieNode<T> node = find(sequence);
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| 102 | if( node!=null ) {
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| 103 | result = node.getFollowingSymbols();
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[1] | 104 | }
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| 105 | return result;
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| 106 | }
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| 107 |
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[5] | 108 | // longest suffix of context, that is contained in the tree and whose children are leaves
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[6] | 109 | // possibly already deprecated
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[1] | 110 | public List<T> getContextSuffix(List<T> context) {
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[5] | 111 | List<T> contextSuffix = new LinkedList<T>(context); // defensive copy
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[1] | 112 | boolean suffixFound = false;
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| 113 |
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| 114 | while(!suffixFound) {
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| 115 | if( contextSuffix.isEmpty() ) {
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| 116 | suffixFound = true; // suffix is the empty word
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| 117 | } else {
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| 118 | TrieNode<T> node = find(contextSuffix);
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| 119 | if( node!=null ) {
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| 120 | if( !node.getFollowingSymbols().isEmpty() ) {
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| 121 | suffixFound = true;
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| 122 | }
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| 123 | }
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[5] | 124 | if( !suffixFound ) {
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| 125 | contextSuffix.remove(0);
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| 126 | }
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[1] | 127 | }
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| 128 | }
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| 129 |
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| 130 | return contextSuffix;
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| 131 | }
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| 132 |
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[5] | 133 |
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| 134 | static public class Edge{}
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| 135 |
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| 136 | static public class TrieVertex {
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| 137 | private String id;
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| 138 | protected TrieVertex(String id) {
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| 139 | this.id = id;
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| 140 | }
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| 141 | public String toString() {
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| 142 | return id;
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| 143 | }
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| 144 | }
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| 145 |
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[23] | 146 | protected Tree<TrieVertex, Edge> getGraph() {
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[5] | 147 | DelegateTree<TrieVertex, Edge> graph = new DelegateTree<TrieVertex, Edge>();
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[6] | 148 | rootNode.getGraph(null, graph);
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[5] | 149 | return graph;
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| 150 | }
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| 151 |
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[30] | 152 | public String getDotRepresentation() {
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| 153 | StringBuilder stringBuilder = new StringBuilder();
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| 154 | stringBuilder.append("digraph model {" + StringTools.ENDLINE);
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| 155 | rootNode.appendDotRepresentation(stringBuilder);
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| 156 | stringBuilder.append('}' + StringTools.ENDLINE);
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| 157 | return stringBuilder.toString();
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| 158 | }
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| 159 |
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[1] | 160 | @Override
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| 161 | public String toString() {
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[6] | 162 | return rootNode.toString();
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[1] | 163 | }
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[66] | 164 |
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| 165 | public int getNumSymbols() {
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| 166 | return knownSymbols.size();
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| 167 | }
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[1] | 168 | }
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