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