Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||||
TransitionTargetComparator |
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1 | /* |
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2 | * |
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3 | * Copyright 2005 The Apache Software Foundation. |
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4 | * |
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5 | * Licensed under the Apache License, Version 2.0 (the "License"); |
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6 | * you may not use this file except in compliance with the License. |
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7 | * You may obtain a copy of the License at |
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8 | * |
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9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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10 | * |
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11 | * Unless required by applicable law or agreed to in writing, software |
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12 | * distributed under the License is distributed on an "AS IS" BASIS, |
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13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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14 | * See the License for the specific language governing permissions and |
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15 | * limitations under the License. |
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16 | * |
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17 | */ |
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18 | package org.apache.commons.scxml.semantics; |
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19 | ||
20 | import java.util.Comparator; |
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21 | ||
22 | import org.apache.commons.scxml.SCXMLHelper; |
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23 | import org.apache.commons.scxml.model.TransitionTarget; |
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24 | ||
25 | ||
26 | /** |
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27 | * A comparator for TransitionTarget instances. |
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28 | * |
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29 | */ |
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30 | final class TransitionTargetComparator implements Comparator { |
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31 | ||
32 | /** |
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33 | * Constructor. |
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34 | */ |
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35 | TransitionTargetComparator() { |
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36 | 43 | super(); |
37 | 43 | } |
38 | ||
39 | /** |
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40 | * Compares two instances of TransitionTarget in terms of the |
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41 | * SCXML tree hierarchy. |
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42 | * <p>Important Remarks:</p> does not fullfill the Comparator contract, |
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43 | * since it returns 0 if o1 == o2 and also if they are not related to each |
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44 | * other and at the same time the chain-to-parent length for o1 is the |
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45 | * same length as for o2 (that is, they are equally deeply nested) |
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46 | * |
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47 | * @param o1 The first TransitionTarget object |
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48 | * @param o2 The second TransitionTarget object |
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49 | * @return int The comparation result |
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50 | * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object) |
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51 | * @see TransitionTarget |
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52 | */ |
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53 | public int compare(final Object o1, final Object o2) { |
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54 | 111 | TransitionTarget tt1 = (TransitionTarget) o1; |
55 | 111 | TransitionTarget tt2 = (TransitionTarget) o2; |
56 | 111 | if (tt1 == tt2) { |
57 | 1 | return 0; |
58 | 110 | } else if (SCXMLHelper.isDescendant(tt1, tt2)) { |
59 | 46 | return -1; |
60 | 64 | } else if (SCXMLHelper.isDescendant(tt2, tt1)) { |
61 | 47 | return 1; |
62 | } else { |
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63 | //the tt1 and tt2 are parallel, now we have to count chain sizes |
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64 | 17 | int tc1 = countChainLength(tt1); |
65 | 17 | int tc2 = countChainLength(tt2); |
66 | //longer the chain, deeper the node is |
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67 | 17 | return tc2 - tc1; |
68 | } |
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69 | } |
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70 | ||
71 | /** |
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72 | * The "depth" at which this TransitionTarget exists in the |
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73 | * SCXML object model. |
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74 | * |
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75 | * @param tt The TransitionTarget |
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76 | * @return int The "depth" |
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77 | */ |
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78 | private int countChainLength(final TransitionTarget tt) { |
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79 | 34 | int count = 0; |
80 | 34 | TransitionTarget parent = tt.getParent(); |
81 | 112 | while (parent != null) { |
82 | 78 | count++; |
83 | 78 | parent = parent.getParent(); |
84 | } |
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85 | 34 | return count; |
86 | } |
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87 | } |
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88 |