[1256] | 1 | // Copyright 2012 Georg-August-Universität Göttingen, Germany |
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| 2 | // |
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| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
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| 4 | // you may not use this file except in compliance with the License. |
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| 5 | // You may obtain a copy of the License at |
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| 6 | // |
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| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
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| 8 | // |
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| 9 | // Unless required by applicable law or agreed to in writing, software |
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| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
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| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 12 | // See the License for the specific language governing permissions and |
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| 13 | // limitations under the License. |
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| 14 | |
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| 15 | package de.ugoe.cs.autoquest.tasktrees.temporalrelation; |
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| 16 | |
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| 17 | import java.util.HashMap; |
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| 18 | import java.util.LinkedList; |
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| 19 | import java.util.List; |
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| 20 | import java.util.Map; |
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[1853] | 21 | import java.util.logging.Level; |
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[1256] | 22 | |
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[1285] | 23 | import de.ugoe.cs.autoquest.tasktrees.treeifc.ITask; |
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[1256] | 24 | import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskInstance; |
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| 25 | import de.ugoe.cs.autoquest.tasktrees.treeifc.IUserSession; |
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| 26 | import de.ugoe.cs.autoquest.usageprofiles.SymbolMap; |
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| 27 | import de.ugoe.cs.autoquest.usageprofiles.Trie; |
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| 28 | import de.ugoe.cs.autoquest.usageprofiles.TrieProcessor; |
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[1853] | 29 | import de.ugoe.cs.util.console.Console; |
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[1256] | 30 | |
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| 31 | /** |
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| 32 | * <p> |
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[1401] | 33 | * This trie implementation is a performance optimization for generating task trees. It does not |
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| 34 | * create a full trie but adds only those subsequences having a chance of occurring most often. |
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| 35 | * For this, it initially counts the number of occurrences of each task instance. Then, during |
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| 36 | * training, it regularly determines the number of the currently most often occurring sequence. If |
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| 37 | * this number is higher than the count of a task instance to be trained, the task instance is |
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| 38 | * skipped the not added to the trie. |
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[1256] | 39 | * </p> |
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| 40 | * |
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| 41 | * @author Patrick Harms |
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| 42 | */ |
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[1853] | 43 | class TaskInstanceTrie extends Trie<ITask> { |
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[1256] | 44 | |
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| 45 | /** */ |
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| 46 | private static final long serialVersionUID = 1L; |
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| 47 | |
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| 48 | /** |
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| 49 | * <p> |
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[1401] | 50 | * the task handling strategy to be used for comparing tasks |
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[1256] | 51 | * </p> |
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| 52 | */ |
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[1285] | 53 | private TaskHandlingStrategy taskStrategy; |
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| 54 | |
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[1256] | 55 | /** |
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| 56 | * <p> |
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[1401] | 57 | * instantiated the trie with the task handling strategy to be used |
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[1256] | 58 | * </p> |
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| 59 | * |
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[1401] | 60 | * @param taskStrategy the task handling strategy to be used for comparing tasks |
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[1256] | 61 | */ |
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[1285] | 62 | public TaskInstanceTrie(TaskHandlingStrategy taskStrategy) { |
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| 63 | super(taskStrategy); |
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| 64 | this.taskStrategy = taskStrategy; |
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[1256] | 65 | } |
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| 66 | |
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| 67 | /** |
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[1401] | 68 | * <p> |
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| 69 | * trains this trie with the provided user sessions up to the provided maximum depth using |
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| 70 | * the optimization described in the description of this class. |
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| 71 | * </p> |
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| 72 | * |
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| 73 | * @param userSessions the sessions for which this trie is to be trained |
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| 74 | * @param maxOrder the depth of the trie |
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[1256] | 75 | */ |
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| 76 | public void trainSessions(List<IUserSession> userSessions, int maxOrder) { |
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| 77 | if (maxOrder < 1) { |
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| 78 | return; |
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| 79 | } |
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| 80 | |
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[1853] | 81 | SymbolMap<ITask, Counter> equalTaskInstancesMap = |
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[1285] | 82 | taskStrategy.createSymbolMap(); |
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[1256] | 83 | |
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[1285] | 84 | Map<ITask, Counter> instanceCountMap = new HashMap<ITask, Counter>(); |
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[1256] | 85 | |
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[1853] | 86 | Console.traceln(Level.FINEST, "preparing training"); |
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[1285] | 87 | int noOfTaskInstances = 0; |
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[1256] | 88 | for (IUserSession session : userSessions) { |
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| 89 | for (ITaskInstance taskInstance : session) { |
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[1853] | 90 | Counter counter = equalTaskInstancesMap.getValue(taskInstance.getTask()); |
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[1256] | 91 | |
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[1285] | 92 | if (counter == null) { |
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| 93 | counter = new Counter(); |
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[1853] | 94 | equalTaskInstancesMap.addSymbol(taskInstance.getTask(), counter); |
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[1256] | 95 | } |
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| 96 | |
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[1285] | 97 | counter.count++; |
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| 98 | instanceCountMap.put(taskInstance.getTask(), counter); |
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| 99 | |
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| 100 | noOfTaskInstances++; |
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[1256] | 101 | } |
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| 102 | } |
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| 103 | |
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[1853] | 104 | Console.traceln |
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| 105 | (Level.FINEST, "performing training of " + noOfTaskInstances + " task instances"); |
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| 106 | |
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[1285] | 107 | Counter processedTaskInstances = new Counter(); |
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| 108 | int counterRecheckAt = noOfTaskInstances / 10; // recheck the maximum count after each |
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| 109 | // 10% of processed task instances |
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[1256] | 110 | for (IUserSession session : userSessions) { |
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[1285] | 111 | train(session, maxOrder, instanceCountMap, processedTaskInstances, counterRecheckAt); |
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[1256] | 112 | } |
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| 113 | |
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| 114 | updateKnownSymbols(); |
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| 115 | } |
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| 116 | |
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[1267] | 117 | /* (non-Javadoc) |
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| 118 | * @see de.ugoe.cs.autoquest.usageprofiles.Trie#equals(java.lang.Object) |
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| 119 | */ |
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| 120 | @Override |
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| 121 | public boolean equals(Object other) { |
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| 122 | if (this == other) { |
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| 123 | return true; |
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| 124 | } |
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| 125 | else if (other instanceof TaskInstanceTrie) { |
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| 126 | return super.equals(other); |
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| 127 | } |
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| 128 | else { |
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| 129 | return false; |
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| 130 | } |
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| 131 | } |
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| 132 | |
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[1273] | 133 | /* (non-Javadoc) |
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| 134 | * @see de.ugoe.cs.autoquest.usageprofiles.Trie#hashCode() |
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| 135 | */ |
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| 136 | @Override |
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| 137 | public int hashCode() { |
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| 138 | return super.hashCode(); |
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| 139 | } |
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| 140 | |
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[1256] | 141 | /** |
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[1401] | 142 | * <p> |
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| 143 | * internally used convenience method for implementing the training optimization |
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| 144 | * </p> |
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[1256] | 145 | */ |
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[1285] | 146 | private void train(IUserSession userSession, |
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| 147 | int maxOrder, |
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| 148 | Map<ITask, Counter> taskInstanceCountMap, |
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| 149 | Counter processedTaskInstances, |
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| 150 | int counterRecheckAt) |
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[1256] | 151 | { |
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[1853] | 152 | List<ITask> subsequence = new LinkedList<ITask>(); |
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[1256] | 153 | |
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| 154 | int sequenceMaxCount = 0; |
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| 155 | |
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[1401] | 156 | for (ITaskInstance currentTaskInstance : userSession) { |
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[1256] | 157 | |
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[1285] | 158 | int occurrenceCount = taskInstanceCountMap.get(currentTaskInstance.getTask()).count; |
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| 159 | |
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| 160 | if (processedTaskInstances.count >= counterRecheckAt) { |
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[1256] | 161 | sequenceMaxCount = getCurrentSequenceMaxCount(); |
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[1285] | 162 | processedTaskInstances.count = 0; |
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[1256] | 163 | } |
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| 164 | |
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| 165 | if (occurrenceCount < sequenceMaxCount) { |
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| 166 | // this task instance does not need to be considered, as it occurs not often enough |
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| 167 | // to be part of a sequence, that occurs most often. Therefore train all remaining |
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| 168 | // sequences so far and go on, until the next useful sequence is found. |
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| 169 | |
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| 170 | while (subsequence.size() > 1) { |
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| 171 | add(subsequence); |
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| 172 | subsequence.remove(0); |
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| 173 | } |
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| 174 | |
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| 175 | subsequence.clear(); |
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| 176 | } |
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| 177 | else { |
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[1853] | 178 | subsequence.add(currentTaskInstance.getTask()); |
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[1256] | 179 | |
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| 180 | if (subsequence.size() == maxOrder) { |
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| 181 | add(subsequence); |
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| 182 | subsequence.remove(0); |
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| 183 | } |
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| 184 | } |
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[1285] | 185 | |
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| 186 | processedTaskInstances.count++; |
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[1256] | 187 | } |
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| 188 | |
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| 189 | // add shorter remaining subsequences, if any |
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| 190 | while (subsequence.size() > 1) { |
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| 191 | add(subsequence); |
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| 192 | subsequence.remove(0); |
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| 193 | } |
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| 194 | } |
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| 195 | |
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| 196 | /** |
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| 197 | * <p> |
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[1401] | 198 | * determines the current maximum count of sequences of a minimal length of two. Task instances |
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| 199 | * occuring more seldom do not have to be considered anymore |
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[1256] | 200 | * </p> |
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| 201 | * |
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[1401] | 202 | * @return the current maximum count of sequences of a minimal length of two |
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[1256] | 203 | */ |
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| 204 | private int getCurrentSequenceMaxCount() { |
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| 205 | MaxSequenceCountFinder processor = new MaxSequenceCountFinder(); |
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| 206 | super.process(processor); |
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| 207 | return processor.getMaxCount(); |
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| 208 | } |
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| 209 | |
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| 210 | /** |
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[1401] | 211 | * <p> |
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| 212 | * trie processor identifying the current maximum count of sequences of a minimal length of two |
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| 213 | * </p> |
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| 214 | * |
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[1256] | 215 | * @author Patrick Harms |
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| 216 | */ |
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[1853] | 217 | private static class MaxSequenceCountFinder implements TrieProcessor<ITask> { |
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[1256] | 218 | |
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| 219 | /** |
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[1401] | 220 | * <p> |
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| 221 | * the current maximum count |
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| 222 | * </p> |
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[1256] | 223 | */ |
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| 224 | private int currentCount = 0; |
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| 225 | |
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| 226 | /* (non-Javadoc) |
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| 227 | * @see de.ugoe.cs.autoquest.usageprofiles.TrieProcessor#process(java.util.List, int) |
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| 228 | */ |
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| 229 | @Override |
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[1853] | 230 | public TrieProcessor.Result process(List<ITask> foundTask, int count) { |
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[1256] | 231 | if (foundTask.size() == 2) { |
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| 232 | this.currentCount = Math.max(this.currentCount, count); |
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| 233 | |
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| 234 | // do not consider children |
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| 235 | return TrieProcessor.Result.SKIP_NODE; |
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| 236 | } |
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| 237 | else { |
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| 238 | return TrieProcessor.Result.CONTINUE; |
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| 239 | } |
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| 240 | } |
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| 241 | |
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| 242 | /** |
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[1401] | 243 | * <p> |
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| 244 | * returns the current maximum count |
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| 245 | * </p> |
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[1256] | 246 | */ |
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| 247 | private int getMaxCount() { |
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| 248 | return currentCount; |
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| 249 | } |
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| 250 | |
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| 251 | } |
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| 252 | |
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[1285] | 253 | /** |
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[1401] | 254 | * <p> |
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| 255 | * counter object to be able to call something by the counters reference |
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| 256 | * </p> |
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| 257 | * |
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[1285] | 258 | * @author Patrick Harms |
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| 259 | */ |
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| 260 | private static class Counter { |
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| 261 | int count = 0; |
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| 262 | } |
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| 263 | |
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[1256] | 264 | } |
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