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.taskequality; |
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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.ISelection; |
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20 | import de.ugoe.cs.autoquest.tasktrees.treeifc.ITask; |
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21 | |
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22 | /** |
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23 | * <p> |
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24 | * this task comparison rule is capable of comparing selections. If both selections do not have |
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25 | * children, they are treated as lexically equal. If they have children, each child of both |
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26 | * selections is compared to each child of the respective other selection. The resulting equality |
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27 | * is the most concrete one of all these comparisons. I.e. if all children are at least lexically |
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28 | * equal, then the selections are lexically equal. If all children are at least syntactically |
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29 | * equal, then the selections are syntactically equal. If all children are at least semantically |
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30 | * equal, then the selections are semantically equal. If only one of the selections has children, |
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31 | * then the selections are unequal. The comparison is broken up, if only a specific equality is |
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32 | * checked for and this equality is ensured. |
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33 | * </p> |
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34 | * |
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35 | * @version $Revision: $ $Date: 19.02.2012$ |
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36 | * @author 2012, last modified by $Author: patrick$ |
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37 | */ |
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38 | public class SelectionComparisonRule implements TaskComparisonRule { |
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39 | |
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40 | /** the rule manager for internally comparing tasks */ |
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41 | private TaskEqualityRuleManager mRuleManager; |
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42 | |
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43 | /** |
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44 | * <p> |
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45 | * simple constructor to provide the rule with the task equality rule manager to be able |
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46 | * to perform comparisons of the children of provided tasks |
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47 | * </p> |
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48 | * |
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49 | * @param ruleManager the rule manager for comparing tasks |
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50 | */ |
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51 | SelectionComparisonRule(TaskEqualityRuleManager ruleManager) { |
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52 | super(); |
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53 | mRuleManager = ruleManager; |
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54 | } |
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55 | |
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56 | /* (non-Javadoc) |
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57 | * @see NodeComparisonRule#isApplicable(ITask, ITask) |
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58 | */ |
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59 | @Override |
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60 | public boolean isApplicable(ITask task1, ITask task2) { |
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61 | return (task1 instanceof ISelection) && (task2 instanceof ISelection); |
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62 | } |
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63 | |
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64 | /* (non-Javadoc) |
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65 | * @see NodeComparisonRule#areLexicallyEqual(ITask, ITask) |
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66 | */ |
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67 | @Override |
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68 | public boolean areLexicallyEqual(ITask task1, ITask task2) { |
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69 | TaskEquality equality = getEquality(task1, task2, TaskEquality.LEXICALLY_EQUAL); |
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70 | return (equality != null) && (equality.isAtLeast(TaskEquality.LEXICALLY_EQUAL)); |
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71 | } |
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72 | |
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73 | /* (non-Javadoc) |
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74 | * @see NodeComparisonRule#areSyntacticallyEqual(ITask, ITask) |
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75 | */ |
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76 | @Override |
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77 | public boolean areSyntacticallyEqual(ITask task1, ITask task2) { |
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78 | TaskEquality equality = getEquality(task1, task2, TaskEquality.SYNTACTICALLY_EQUAL); |
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79 | return (equality != null) && (equality.isAtLeast(TaskEquality.SYNTACTICALLY_EQUAL)); |
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80 | } |
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81 | |
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82 | /* (non-Javadoc) |
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83 | * @see NodeComparisonRule#areSemanticallyEqual(ITask, ITask) |
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84 | */ |
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85 | @Override |
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86 | public boolean areSemanticallyEqual(ITask task1, ITask task2) { |
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87 | TaskEquality equality = getEquality(task1, task2, TaskEquality.SEMANTICALLY_EQUAL); |
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88 | return (equality != null) && (equality.isAtLeast(TaskEquality.SEMANTICALLY_EQUAL)); |
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89 | } |
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90 | |
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91 | /* (non-Javadoc) |
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92 | * @see NodeComparisonRule#compare(ITask, ITask) |
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93 | */ |
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94 | @Override |
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95 | public TaskEquality compare(ITask task1, ITask task2) { |
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96 | return getEquality(task1, task2, null); |
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97 | } |
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98 | |
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99 | /** |
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100 | * <p> |
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101 | * compares two selections with each other checking for the provided required level of |
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102 | * equality. If this level is ensured, the method immediately returns. The more concrete |
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103 | * the required equality level, the more checks this method performs. |
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104 | * </p> |
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105 | * |
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106 | * @param task1 the first task to be compared |
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107 | * @param task2 the second task to be compared |
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108 | * @param requiredEqualityLevel the equality level to be checked for |
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109 | * |
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110 | * @return the determined equality. |
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111 | */ |
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112 | private TaskEquality getEquality(ITask task1, ITask task2, TaskEquality requiredEqualityLevel) { |
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113 | List<ITask> children1 = ((ISelection) task1).getChildren(); |
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114 | List<ITask> children2 = ((ISelection) task2).getChildren(); |
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115 | |
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116 | // if both selections do not have children, they are lexically equal. If only one of them |
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117 | // has children, they are unequal. |
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118 | if ((children1.size() == 0) && (children2.size() == 0)) { |
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119 | return TaskEquality.LEXICALLY_EQUAL; |
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120 | } |
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121 | else if ((children1.size() == 0) || (children2.size() == 0)) { |
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122 | return TaskEquality.UNEQUAL; |
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123 | } |
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124 | |
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125 | TaskEquality selectionEquality; |
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126 | |
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127 | if (requiredEqualityLevel == null) { |
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128 | // calculate the common equality level for all children of both selections. |
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129 | // do it in both directions to ensure commutative comparison |
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130 | selectionEquality = getCommonEqualityLevel(children1, children2); |
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131 | if (selectionEquality != TaskEquality.UNEQUAL) { |
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132 | return selectionEquality.getCommonDenominator |
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133 | (getCommonEqualityLevel(children2, children1)); |
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134 | } |
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135 | else { |
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136 | return TaskEquality.UNEQUAL; |
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137 | } |
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138 | } |
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139 | else { |
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140 | // we are searching for a specific equality |
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141 | if (checkEqualityLevel(children1, children2, requiredEqualityLevel) && |
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142 | checkEqualityLevel(children2, children1, requiredEqualityLevel)) |
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143 | { |
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144 | return requiredEqualityLevel; |
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145 | } |
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146 | else { |
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147 | return TaskEquality.UNEQUAL; |
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148 | } |
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149 | } |
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150 | } |
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151 | |
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152 | /** |
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153 | * <p> |
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154 | * determines the common equality level for all tasks in the first list compared to all |
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155 | * tasks in the second list. If for one task in the first list, there is no equal task in the |
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156 | * second list, the method return unequality. |
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157 | * </p> |
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158 | * |
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159 | * @param children1 the first list to be compared |
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160 | * @param children2 the second list to be compared |
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161 | * |
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162 | * @return the common task equality identified for all tasks in the first list with respect to |
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163 | * the second list |
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164 | */ |
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165 | private TaskEquality getCommonEqualityLevel(List<ITask> children1, List<ITask> children2) { |
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166 | TaskEquality listEquality = TaskEquality.LEXICALLY_EQUAL; |
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167 | |
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168 | TaskEquality childEquality; |
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169 | TaskEquality currentEquality; |
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170 | for (ITask child1 : children1) { |
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171 | childEquality = null; |
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172 | for (ITask child2 : children2) { |
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173 | currentEquality = callRuleManager(child1, child2, null); |
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174 | if ((currentEquality != null) && (currentEquality != TaskEquality.UNEQUAL)) { |
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175 | if (childEquality == null) { |
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176 | childEquality = currentEquality; |
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177 | } |
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178 | else { |
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179 | childEquality = childEquality.getCommonDenominator(currentEquality); |
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180 | } |
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181 | |
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182 | if (childEquality == TaskEquality.SEMANTICALLY_EQUAL) { |
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183 | // as we calculate only the common denominator, we can break up here for |
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184 | // the current child. We will not improve the denominator anymore |
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185 | break; |
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186 | } |
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187 | } |
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188 | } |
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189 | |
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190 | if (childEquality == null) { |
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191 | // we did not find any child in the second list, that is equal to the searched |
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192 | // child |
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193 | return TaskEquality.UNEQUAL; |
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194 | } |
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195 | else { |
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196 | listEquality = listEquality.getCommonDenominator(childEquality); |
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197 | } |
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198 | } |
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199 | |
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200 | return listEquality; |
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201 | } |
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202 | |
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203 | /** |
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204 | * <p> |
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205 | * ensures for the two given lists, that for each task in the first list there is a task |
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206 | * in the second list being on the given level equal to the task in the first list. |
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207 | * </p> |
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208 | * |
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209 | * @param children1 the first list to be compared |
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210 | * @param children2 the second list to be compared |
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211 | * @param requiredEqualityLevel the equality level to be checked for |
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212 | * |
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213 | * @return true if each task in the first list has an equal task in the second list when |
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214 | * considering the given equality level, false else. |
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215 | */ |
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216 | private boolean checkEqualityLevel(List<ITask> children1, |
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217 | List<ITask> children2, |
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218 | TaskEquality requiredEqualityLevel) |
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219 | { |
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220 | TaskEquality childEquality; |
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221 | TaskEquality currentEquality; |
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222 | for (ITask child1 : children1) { |
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223 | childEquality = null; |
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224 | for (ITask child2 : children2) { |
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225 | currentEquality = callRuleManager(child1, child2, requiredEqualityLevel); |
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226 | if ((currentEquality != null) && (currentEquality.isAtLeast(requiredEqualityLevel))) |
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227 | { |
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228 | // we found at least one equal child with sufficient equality in the |
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229 | // second list. So be can break up for this child. |
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230 | childEquality = currentEquality; |
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231 | break; |
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232 | } |
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233 | } |
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234 | |
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235 | if (childEquality == null) { |
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236 | // we did not find any child in the second list, that is equal to the searched |
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237 | // child |
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238 | return false; |
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239 | } |
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240 | } |
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241 | |
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242 | // for all children, we found an equality |
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243 | return true; |
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244 | } |
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245 | |
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246 | /** |
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247 | * <p> |
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248 | * used to to call the task equality rule manager for the comparison of the two provided |
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249 | * children. If no required equality level is provided, than the most concrete equality is |
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250 | * returned. Otherwise, the required equality is returned as long as the children are equal |
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251 | * on that level. |
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252 | * </p> |
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253 | * |
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254 | * @param child1 the first task to be compared |
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255 | * @param child2 the second task to be compared |
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256 | * @param requiredEqualityLevel the equality level to be checked for |
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257 | * |
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258 | * @return the determined equality |
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259 | */ |
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260 | private TaskEquality callRuleManager(ITask child1, |
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261 | ITask child2, |
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262 | TaskEquality requiredEqualityLevel) |
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263 | { |
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264 | if (requiredEqualityLevel == null) { |
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265 | return mRuleManager.compare(child1, child2); |
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266 | } |
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267 | else if (mRuleManager.areAtLeastEqual(child1, child2, requiredEqualityLevel)) { |
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268 | return requiredEqualityLevel; |
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269 | } |
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270 | else { |
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271 | return TaskEquality.UNEQUAL; |
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272 | } |
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273 | } |
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274 | |
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275 | } |
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