[1127] | 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.List; |
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| 18 | |
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| 19 | import de.ugoe.cs.autoquest.tasktrees.treeifc.IIteration; |
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| 20 | import de.ugoe.cs.autoquest.tasktrees.treeifc.IOptional; |
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| 21 | import de.ugoe.cs.autoquest.tasktrees.treeifc.ISelection; |
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| 22 | import de.ugoe.cs.autoquest.tasktrees.treeifc.ISequence; |
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| 23 | import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskTreeBuilder; |
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| 24 | import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskTreeNode; |
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| 25 | import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskTreeNodeFactory; |
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| 26 | import difflib.ChangeDelta; |
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| 27 | import difflib.Chunk; |
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| 28 | import difflib.DeleteDelta; |
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| 29 | import difflib.Delta; |
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| 30 | import difflib.InsertDelta; |
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| 31 | import difflib.Patch; |
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| 32 | import difflib.myers.DiffNode; |
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| 33 | import difflib.myers.MyersDiff; |
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| 34 | import difflib.myers.PathNode; |
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| 35 | import difflib.myers.Snake; |
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| 36 | |
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| 37 | /** |
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| 38 | * <p> |
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| 39 | * TODO comment |
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| 40 | * </p> |
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| 41 | * |
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| 42 | * @author Patrick Harms |
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| 43 | */ |
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| 44 | class TaskTreeNodeMerger { |
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| 45 | |
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| 46 | /** */ |
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| 47 | private ITaskTreeNodeFactory taskTreeNodeFactory; |
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| 48 | |
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| 49 | /** */ |
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| 50 | private ITaskTreeBuilder taskTreeBuilder; |
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| 51 | |
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| 52 | /** */ |
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| 53 | private TaskTreeNodeComparator nodeComparator; |
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| 54 | |
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| 55 | /** |
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| 56 | * <p> |
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| 57 | * TODO: comment |
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| 58 | * </p> |
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| 59 | * |
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| 60 | * @param taskTreeNodeFactory the node factory to be used if nodes must be instantiated |
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| 61 | * @param taskTreeBuilder the task tree builder to be used if nodes must be merged |
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| 62 | * @param nodeEqualityRuleManager the node equality rule manager that may be needed for |
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| 63 | * comparing nodes during merge |
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| 64 | * @param consideredNodeEquality the node equality considered when comparing nodes to |
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| 65 | * identify them as equal |
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| 66 | */ |
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| 67 | TaskTreeNodeMerger(ITaskTreeNodeFactory taskTreeNodeFactory, |
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| 68 | ITaskTreeBuilder taskTreeBuilder, |
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| 69 | TaskTreeNodeComparator nodeComparator) |
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| 70 | { |
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| 71 | super(); |
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| 72 | this.taskTreeNodeFactory = taskTreeNodeFactory; |
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| 73 | this.taskTreeBuilder = taskTreeBuilder; |
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| 74 | this.nodeComparator = nodeComparator; |
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| 75 | } |
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| 76 | |
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| 77 | /** |
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| 78 | * <p> |
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| 79 | * this method merges task tree nodes in a list, if they can be merged. For this, it tries |
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| 80 | * to merge every node with every other node in the provided list using the |
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| 81 | * {@link #mergeTaskNodes(ITaskTreeNode, ITaskTreeNode)} method. If a merge is possible, it |
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| 82 | * removes the merged nodes from the list and adds the merge result. |
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| 83 | * </p> |
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| 84 | * |
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| 85 | * @param nodes the list of nodes to be merged |
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| 86 | */ |
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| 87 | void mergeTaskNodes(List<ITaskTreeNode> nodes) { |
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| 88 | int index1 = 0; |
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| 89 | int index2 = 0; |
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| 90 | ITaskTreeNode variant1; |
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| 91 | ITaskTreeNode variant2; |
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| 92 | |
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| 93 | while (index1 < nodes.size()) { |
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| 94 | variant1 = nodes.get(index1); |
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| 95 | index2 = index1 + 1; |
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| 96 | |
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| 97 | while (index2 < nodes.size()) { |
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| 98 | variant2 = nodes.get(index2); |
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| 99 | ITaskTreeNode mergedChild = mergeTaskNodes(variant1, variant2); |
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| 100 | |
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| 101 | if (mergedChild != null) { |
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| 102 | // if we merged something start from the beginning to perform the next merge |
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| 103 | nodes.remove(index2); |
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| 104 | nodes.remove(index1); |
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| 105 | nodes.add(index1, mergedChild); |
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| 106 | index1 = -1; |
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| 107 | break; |
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| 108 | } |
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| 109 | else { |
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| 110 | index2++; |
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| 111 | } |
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| 112 | } |
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| 113 | |
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| 114 | index1++; |
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| 115 | } |
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| 116 | } |
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| 117 | |
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| 118 | /** |
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| 119 | * <p> |
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| 120 | * this method merges two tasks with each other if possible. If the tasks are lexically |
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| 121 | * equal, the first of them is returned as merge result. If both tasks are of the same |
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| 122 | * temporal relationship type, the appropriate merge method is called to merge them. If one |
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| 123 | * of the nodes is a selection, the other one is added as a variant of this selection. |
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| 124 | * (However, if both nodes are selections, they are merged using the appropriate merge method.) |
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| 125 | * If merging is not possible, then a selection of both provided nodes is created and |
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| 126 | * returned as merge result. |
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| 127 | * </p> |
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| 128 | * |
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| 129 | * @param node1 the first task to be merged |
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| 130 | * @param node2 the second task to be merged |
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| 131 | * |
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| 132 | * @return the result of the merge |
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| 133 | */ |
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| 134 | ITaskTreeNode mergeTaskNodes(ITaskTreeNode node1, ITaskTreeNode node2) { |
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| 135 | ITaskTreeNode mergeResult = null; |
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| 136 | |
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| 137 | // both are of same parent type |
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| 138 | if ((node1 instanceof ISequence) && (node2 instanceof ISequence)) { |
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| 139 | mergeResult = mergeSequences((ISequence) node1, (ISequence) node2); |
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| 140 | } |
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| 141 | else if ((node1 instanceof ISelection) && (node2 instanceof ISelection)) { |
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| 142 | mergeResult = mergeSelections((ISelection) node1, (ISelection) node2); |
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| 143 | } |
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| 144 | else if ((node1 instanceof IIteration) && (node2 instanceof IIteration)) { |
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| 145 | mergeResult = mergeIterations((IIteration) node1, (IIteration) node2); |
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| 146 | } |
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| 147 | else if ((node1 instanceof IOptional) && (node2 instanceof IOptional)) { |
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| 148 | mergeResult = mergeOptionals((IOptional) node1, (IOptional) node2); |
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| 149 | } |
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| 150 | // one is an iteration |
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| 151 | else if (node1 instanceof IIteration) { |
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| 152 | mergeResult = mergeTaskNodes(((IIteration) node1).getChildren().get(0), node2); |
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| 153 | |
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| 154 | if (mergeResult != null) { |
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| 155 | taskTreeBuilder.setChild((IIteration) node1, mergeResult); |
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| 156 | mergeResult = node1; |
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| 157 | } |
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| 158 | } |
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| 159 | else if (node2 instanceof IIteration) { |
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| 160 | mergeResult = mergeTaskNodes(((IIteration) node2).getChildren().get(0), node1); |
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| 161 | |
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| 162 | if (mergeResult != null) { |
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| 163 | taskTreeBuilder.setChild((IIteration) node2, mergeResult); |
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| 164 | mergeResult = node2; |
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| 165 | } |
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| 166 | } |
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| 167 | // one is an optional |
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| 168 | else if (node1 instanceof IOptional) { |
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| 169 | mergeResult = mergeTaskNodes(((IOptional) node1).getChildren().get(0), node2); |
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| 170 | |
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| 171 | if (mergeResult != null) { |
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| 172 | taskTreeBuilder.setChild((IOptional) node1, mergeResult); |
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| 173 | mergeResult = node1; |
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| 174 | } |
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| 175 | } |
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| 176 | else if (node2 instanceof IOptional) { |
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| 177 | mergeResult = mergeTaskNodes(((IOptional) node2).getChildren().get(0), node1); |
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| 178 | |
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| 179 | if (mergeResult != null) { |
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| 180 | taskTreeBuilder.setChild((IOptional) node2, mergeResult); |
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| 181 | mergeResult = node2; |
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| 182 | } |
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| 183 | } |
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| 184 | // one is a selection |
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| 185 | else if (node1 instanceof ISelection) { |
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| 186 | ISelection selection2 = taskTreeNodeFactory.createNewSelection(); |
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| 187 | taskTreeBuilder.addChild(selection2, node2); |
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| 188 | mergeResult = mergeSelections((ISelection) node1, selection2); |
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| 189 | } |
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| 190 | else if (node2 instanceof ISelection) { |
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| 191 | ISelection selection1 = taskTreeNodeFactory.createNewSelection(); |
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| 192 | taskTreeBuilder.addChild(selection1, node1); |
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| 193 | mergeResult = mergeSelections(selection1, (ISelection) node2); |
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| 194 | } |
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| 195 | // one is a sequence |
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| 196 | else if (node1 instanceof ISequence) { |
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| 197 | ISequence sequence2 = taskTreeNodeFactory.createNewSequence(); |
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| 198 | taskTreeBuilder.addChild(sequence2, node2); |
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| 199 | mergeResult = mergeSequences((ISequence) node1, sequence2); |
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| 200 | } |
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| 201 | else if (node2 instanceof ISequence) { |
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| 202 | ISequence sequence1 = taskTreeNodeFactory.createNewSequence(); |
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| 203 | taskTreeBuilder.addChild(sequence1, node1); |
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| 204 | mergeResult = mergeSequences(sequence1, (ISequence) node2); |
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| 205 | } |
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| 206 | // both are event tasks |
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| 207 | else { |
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| 208 | // only drop nodes which are definitely lexically equal |
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| 209 | if (nodeComparator.areLexicallyEqual(node1, node2)) { |
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| 210 | mergeResult = node1; |
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| 211 | } |
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| 212 | } |
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| 213 | |
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| 214 | if (mergeResult == null) { |
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| 215 | mergeResult = taskTreeNodeFactory.createNewSelection(); |
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| 216 | taskTreeBuilder.setDescription(mergeResult, "variants of " + node1); |
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| 217 | taskTreeBuilder.addChild((ISelection) mergeResult, node1); |
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| 218 | taskTreeBuilder.addChild((ISelection) mergeResult, node2); |
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| 219 | } |
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| 220 | |
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| 221 | return mergeResult; |
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| 222 | } |
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| 223 | |
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| 224 | /** |
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| 225 | * <p> |
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| 226 | * merges equal sequences. This is done through performing a diff between the two sequences. |
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| 227 | * For each identified difference appropriate substructures are created. For equal parts, |
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| 228 | * the appropriate equal nodes are merged using |
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| 229 | * {@link #mergeTaskNodes(ITaskTreeNode, ITaskTreeNode)} and the result is added to the |
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| 230 | * overall merge result. |
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| 231 | * </p> |
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| 232 | * |
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| 233 | * @param sequence1 the first sequence to be merged |
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| 234 | * @param sequence2 the second sequence to be merged |
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| 235 | * |
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| 236 | * @return the result of the merge or null if merging was not possible |
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| 237 | */ |
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| 238 | ITaskTreeNode mergeSequences(ISequence sequence1, ISequence sequence2) { |
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| 239 | ITaskTreeNode mergeResult = taskTreeNodeFactory.createNewSequence(); |
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| 240 | |
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| 241 | List<ITaskTreeNode> children1 = sequence1.getChildren(); |
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| 242 | List<ITaskTreeNode> children2 = sequence2.getChildren(); |
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| 243 | |
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| 244 | Patch patch = new TaskTreeNodeSequenceMyersDiff().getDiff(children1, children2); |
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| 245 | |
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| 246 | int index1 = 0; |
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| 247 | int index2 = 0; |
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| 248 | |
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| 249 | while ((index1 < children1.size()) || (index2 < children2.size())) { |
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| 250 | boolean foundDelta = false; |
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| 251 | for (Delta delta : patch.getDeltas()) { |
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| 252 | if ((delta.getOriginal().getPosition() == index1) && |
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| 253 | (delta.getRevised().getPosition() == index2)) |
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| 254 | { |
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| 255 | if (delta.getType() == Delta.TYPE.DELETE) { |
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| 256 | ITaskTreeNode option = getSubTree(children1, delta.getOriginal()); |
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| 257 | index1 += delta.getOriginal().size(); |
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| 258 | |
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| 259 | IOptional optional = taskTreeNodeFactory.createNewOptional(); |
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| 260 | taskTreeBuilder.setChild(optional, option); |
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| 261 | taskTreeBuilder.addChild((ISequence) mergeResult, optional); |
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| 262 | } |
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| 263 | else if (delta.getType() == Delta.TYPE.INSERT) { |
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| 264 | ITaskTreeNode option = getSubTree(children2, delta.getRevised()); |
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| 265 | index2 += delta.getRevised().size(); |
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| 266 | |
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| 267 | IOptional optional = taskTreeNodeFactory.createNewOptional(); |
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| 268 | taskTreeBuilder.setChild(optional, option); |
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| 269 | taskTreeBuilder.addChild((ISequence) mergeResult, optional); |
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| 270 | } |
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| 271 | else { |
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| 272 | ITaskTreeNode variant1 = getSubTree(children1, delta.getOriginal()); |
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| 273 | index1 += delta.getOriginal().size(); |
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| 274 | |
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| 275 | ITaskTreeNode variant2 = getSubTree(children2, delta.getRevised()); |
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| 276 | index2 += delta.getRevised().size(); |
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| 277 | |
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| 278 | ISelection selection = taskTreeNodeFactory.createNewSelection(); |
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| 279 | taskTreeBuilder.addChild(selection, variant1); |
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| 280 | taskTreeBuilder.addChild(selection, variant2); |
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| 281 | taskTreeBuilder.addChild((ISequence) mergeResult, selection); |
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| 282 | } |
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| 283 | |
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| 284 | foundDelta = true; |
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| 285 | } |
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| 286 | } |
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| 287 | |
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| 288 | if (!foundDelta) { |
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| 289 | ITaskTreeNode mergedNode = |
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| 290 | mergeTaskNodes(children1.get(index1++), children2.get(index2++)); |
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| 291 | taskTreeBuilder.addChild((ISequence) mergeResult, mergedNode); |
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| 292 | } |
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| 293 | } |
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| 294 | |
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| 295 | List<ITaskTreeNode> mergeResultChildren = mergeResult.getChildren(); |
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| 296 | if ((mergeResultChildren != null) && (mergeResultChildren.size() == 1) && |
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| 297 | (mergeResultChildren.get(0) instanceof ISelection)) |
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| 298 | { |
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| 299 | mergeResult = mergeResultChildren.get(0); |
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| 300 | } |
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| 301 | |
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| 302 | taskTreeBuilder.setDescription(mergeResult, sequence1.getDescription()); |
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| 303 | |
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| 304 | return mergeResult; |
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| 305 | } |
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| 306 | |
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| 307 | /** |
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| 308 | * <p> |
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| 309 | * merges equal selections. This is done by adding those children of the second selection to |
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| 310 | * the first selection that can not be merged with any of the children of the first selection. |
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| 311 | * If a merge is possible and this merge is not a simple selection of the merged children, |
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| 312 | * then the merged child replaces the child of the first selection which was merged. |
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| 313 | * </p> |
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| 314 | * |
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| 315 | * @param selection1 the first selection to be merged |
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| 316 | * @param selection2 the second selection to be merged |
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| 317 | * |
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| 318 | * @return the result of the merge which is never null |
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| 319 | */ |
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| 320 | ITaskTreeNode mergeSelections(ISelection selection1, ISelection selection2) { |
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| 321 | ISelection mergeResult = selection1; |
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| 322 | |
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| 323 | ITaskTreeNode childToMerge = null; |
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| 324 | ITaskTreeNode mergedChild = null; |
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| 325 | |
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| 326 | List<ITaskTreeNode> children1 = selection1.getChildren(); |
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| 327 | List<ITaskTreeNode> children2 = selection2.getChildren(); |
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| 328 | |
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| 329 | // check for each child of selection 2 if it is a duplicate of one of the children |
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| 330 | // if selection 1. If not, add it as further child to the merge result, else skip it. |
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| 331 | for (int i = 0; i < children2.size(); i++) { |
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| 332 | childToMerge = children2.get(i); |
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| 333 | for (int j = 0; j < children1.size(); j++) { |
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| 334 | mergedChild = mergeTaskNodes(children1.get(j), childToMerge); |
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| 335 | |
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| 336 | // a merge must not be a selection, except it is one of the children. Otherwise |
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| 337 | // no real merge was done. |
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| 338 | if ((mergedChild != null) && |
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| 339 | ((!(mergedChild instanceof ISelection)) || |
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| 340 | (children1.get(j) == mergedChild) || (childToMerge == mergedChild))) |
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| 341 | { |
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| 342 | // we found a real merge. So replace the original child in selection 1 with |
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| 343 | // the merged child |
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| 344 | taskTreeBuilder.removeChild(selection1, children1.get(j)); |
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| 345 | taskTreeBuilder.addChild(selection1, mergedChild); |
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| 346 | mergedChild = null; |
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| 347 | childToMerge = null; |
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| 348 | break; |
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| 349 | } |
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| 350 | } |
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| 351 | |
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| 352 | if (childToMerge != null) { |
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| 353 | taskTreeBuilder.addChild(selection1, childToMerge); |
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| 354 | } |
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| 355 | } |
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| 356 | |
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| 357 | return mergeResult; |
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| 358 | } |
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| 359 | |
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| 360 | /** |
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| 361 | * <p> |
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| 362 | * merges equal iterations. This is done through merging the children of both iterations. If |
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| 363 | * this is possible, a resulting iteration with the merge result of the children as its own |
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| 364 | * child is returned. Otherwise null is returned to indicate that merging was not possible. |
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| 365 | * </p> |
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| 366 | * |
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| 367 | * @param iteration1 the first iteration to be merged |
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| 368 | * @param iteration2 the second iteration to be merged |
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| 369 | * |
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| 370 | * @return the result of the merge or null if merging is not possible |
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| 371 | */ |
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| 372 | ITaskTreeNode mergeIterations(IIteration iteration1, IIteration iteration2) { |
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| 373 | ITaskTreeNode mergedChild = mergeTaskNodes |
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| 374 | (iteration1.getChildren().get(0), iteration2.getChildren().get(0)); |
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| 375 | |
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| 376 | IIteration mergeResult = null; |
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| 377 | |
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| 378 | if (mergedChild != null) { |
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| 379 | mergeResult = iteration1; |
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| 380 | taskTreeBuilder.setChild(mergeResult, mergedChild); |
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| 381 | } |
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| 382 | |
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| 383 | return mergeResult; |
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| 384 | } |
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| 385 | |
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| 386 | /** |
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| 387 | * <p> |
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| 388 | * merges equal optionals. This is done through merging the children of both optionals. If |
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| 389 | * this is possible, a resulting optional with the merge result of the children as its own |
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| 390 | * child is returned. Otherwise null is returned to indicate that merging was not possible. |
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| 391 | * </p> |
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| 392 | * |
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| 393 | * @param optional1 the first optional to be merged |
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| 394 | * @param optional2 the second optional to be merged |
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| 395 | * |
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| 396 | * @return the result of the merge or null if merging is not possible |
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| 397 | */ |
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| 398 | ITaskTreeNode mergeOptionals(IOptional optional1, IOptional optional2) { |
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| 399 | ITaskTreeNode mergedChild = mergeTaskNodes |
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| 400 | (optional1.getChildren().get(0), optional2.getChildren().get(0)); |
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| 401 | |
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| 402 | IOptional mergeResult = null; |
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| 403 | |
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| 404 | if (mergedChild != null) { |
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| 405 | mergeResult = optional1; |
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| 406 | taskTreeBuilder.setChild(mergeResult, mergedChild); |
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| 407 | } |
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| 408 | |
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| 409 | return mergeResult; |
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| 410 | } |
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| 411 | |
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| 412 | /** |
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| 413 | * <p> |
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| 414 | * determines a task tree node defined by the provided chunk. This is either a single node if |
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| 415 | * the chunck denotes a single child, or it is a sequence of the denoted children. |
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| 416 | * </p> |
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| 417 | */ |
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| 418 | private ITaskTreeNode getSubTree(List<ITaskTreeNode> children1, Chunk chunk) { |
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| 419 | ITaskTreeNode part; |
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| 420 | |
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| 421 | if (chunk.size() == 1) { |
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| 422 | part = children1.get(chunk.getPosition()); |
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| 423 | } |
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| 424 | else { |
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| 425 | part = taskTreeNodeFactory.createNewSequence(); |
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| 426 | |
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| 427 | for (int i = 0; i < chunk.size(); i++) { |
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| 428 | taskTreeBuilder.addChild |
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| 429 | ((ISequence) part, children1.get(chunk.getPosition() + i)); |
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| 430 | } |
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| 431 | } |
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| 432 | |
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| 433 | return part; |
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| 434 | } |
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| 435 | |
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| 436 | /** |
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| 437 | * |
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| 438 | */ |
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| 439 | private class TaskTreeNodeSequenceMyersDiff extends MyersDiff { |
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| 440 | |
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| 441 | /** |
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| 442 | * |
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| 443 | */ |
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| 444 | private Patch getDiff(List<ITaskTreeNode> variant1, List<ITaskTreeNode> variant2) { |
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| 445 | PathNode path = buildPath(variant1, variant2); |
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| 446 | return buildRevision(path, variant1, variant2); |
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| 447 | } |
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| 448 | |
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| 449 | /** |
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| 450 | * overwrites the default implementation just to change the tree node comparison. |
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| 451 | * This is an extended version of the original implementation respecting the appropriate |
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| 452 | * copyrights. Please see the copyrights of the implementers of the base class for more |
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| 453 | * information |
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| 454 | */ |
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| 455 | private PathNode buildPath(List<ITaskTreeNode> variant1, List<ITaskTreeNode> variant2) { |
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| 456 | if (variant1 == null) { |
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| 457 | throw new IllegalArgumentException("variant1 is null"); |
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| 458 | } |
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| 459 | |
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| 460 | if (variant2 == null) { |
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| 461 | throw new IllegalArgumentException("variant2 is null"); |
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| 462 | } |
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| 463 | |
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| 464 | // these are local constants |
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| 465 | final int N = variant1.size(); |
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| 466 | final int M = variant2.size(); |
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| 467 | |
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| 468 | final int MAX = N + M + 1; |
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| 469 | final int size = 1 + 2 * MAX; |
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| 470 | final int middle = size / 2; |
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| 471 | final PathNode diagonal[] = new PathNode[size]; |
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| 472 | |
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| 473 | diagonal[middle + 1] = new Snake(0, -1, null); |
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| 474 | |
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| 475 | for (int d = 0; d < MAX; d++) { |
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| 476 | for (int k = -d; k <= d; k += 2) { |
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| 477 | final int kmiddle = middle + k; |
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| 478 | final int kplus = kmiddle + 1; |
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| 479 | final int kminus = kmiddle - 1; |
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| 480 | PathNode prev = null; |
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| 481 | |
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| 482 | int i; |
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| 483 | if ((k == -d) || ((k != d) && (diagonal[kminus].i < diagonal[kplus].i))) { |
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| 484 | i = diagonal[kplus].i; |
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| 485 | prev = diagonal[kplus]; |
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| 486 | } |
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| 487 | else { |
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| 488 | i = diagonal[kminus].i + 1; |
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| 489 | prev = diagonal[kminus]; |
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| 490 | } |
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| 491 | |
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| 492 | diagonal[kminus] = null; // no longer used |
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| 493 | |
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| 494 | int j = i - k; |
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| 495 | |
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| 496 | PathNode node = new DiffNode(i, j, prev); |
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| 497 | |
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| 498 | // orig and rev are zero-based |
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| 499 | // but the algorithm is one-based |
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| 500 | // that's why there's no +1 when indexing the sequences |
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| 501 | while ((i < N) && (j < M) && |
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| 502 | nodeComparator.equals(variant1.get(i), variant2.get(j))) |
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| 503 | { |
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| 504 | i++; |
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| 505 | j++; |
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| 506 | } |
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| 507 | |
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| 508 | if (i > node.i) { |
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| 509 | node = new Snake(i, j, node); |
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| 510 | } |
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| 511 | |
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| 512 | diagonal[kmiddle] = node; |
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| 513 | |
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| 514 | if ((i >= N) && (j >= M)) { |
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| 515 | return diagonal[kmiddle]; |
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| 516 | } |
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| 517 | } |
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| 518 | diagonal[middle + d - 1] = null; |
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| 519 | |
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| 520 | } |
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| 521 | |
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| 522 | // According to Myers, this cannot happen |
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| 523 | throw new RuntimeException("could not find a diff path"); |
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| 524 | } |
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| 525 | |
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| 526 | /** |
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| 527 | * overwrites the default implementation just to change the tree node comparison. |
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| 528 | * This is an extended version of the original implementation respecting the appropriate |
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| 529 | * copyrights. Please see the copyrights of the implementers of the base class for more |
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| 530 | * information |
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| 531 | */ |
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| 532 | private Patch buildRevision(PathNode path, |
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| 533 | List<ITaskTreeNode> variant1, |
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| 534 | List<ITaskTreeNode> variant2) |
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| 535 | { |
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| 536 | if (path == null) { |
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| 537 | throw new IllegalArgumentException("path is null"); |
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| 538 | } |
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| 539 | |
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| 540 | if (variant1 == null) { |
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| 541 | throw new IllegalArgumentException("variant1 is null"); |
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| 542 | } |
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| 543 | |
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| 544 | if (variant2 == null) { |
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| 545 | throw new IllegalArgumentException("variant2 is null"); |
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| 546 | } |
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| 547 | |
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| 548 | Patch patch = new Patch(); |
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| 549 | if (path.isSnake()) { |
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| 550 | path = path.prev; |
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| 551 | } |
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| 552 | |
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| 553 | while ((path != null) && (path.prev != null) && (path.prev.j >= 0)) { |
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| 554 | if (path.isSnake()) { |
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| 555 | throw new IllegalStateException |
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| 556 | ("bad diffpath: found snake when looking for diff"); |
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| 557 | } |
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| 558 | |
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| 559 | int i = path.i; |
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| 560 | int j = path.j; |
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| 561 | |
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| 562 | path = path.prev; |
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| 563 | int ianchor = path.i; |
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| 564 | int janchor = path.j; |
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| 565 | |
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| 566 | Chunk original = new Chunk(ianchor, variant1.subList(ianchor, i)); |
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| 567 | Chunk revised = new Chunk(janchor, variant2.subList(janchor, j)); |
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| 568 | Delta delta = null; |
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| 569 | |
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| 570 | if ((original.size() == 0) && (revised.size() != 0)) { |
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| 571 | delta = new InsertDelta(original, revised); |
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| 572 | } |
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| 573 | else if ((original.size() > 0) && (revised.size() == 0)) { |
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| 574 | delta = new DeleteDelta(original, revised); |
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| 575 | } |
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| 576 | else { |
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| 577 | delta = new ChangeDelta(original, revised); |
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| 578 | } |
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| 579 | |
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| 580 | patch.addDelta(delta); |
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| 581 | |
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| 582 | if (path.isSnake()) { |
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| 583 | path = path.prev; |
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| 584 | } |
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| 585 | } |
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| 586 | return patch; |
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| 587 | } |
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| 588 | |
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| 589 | } |
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| 590 | } |
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