1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one |
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3 | * or more contributor license agreements. See the NOTICE file |
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4 | * distributed with this work for additional information |
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5 | * regarding copyright ownership. The ASF licenses this file |
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6 | * to you under the Apache License, Version 2.0 (the |
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7 | * "License"); you may not use this file except in compliance |
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8 | * with the License. You may obtain a copy of the License at |
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9 | * |
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10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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11 | * |
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12 | * Unless required by applicable law or agreed to in writing, software |
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13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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15 | * See the License for the specific language governing permissions and |
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16 | * limitations under the License. |
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17 | */ |
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18 | |
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19 | package org.apache.hadoop.util; |
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20 | |
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21 | import java.util.ArrayList; |
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22 | |
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23 | /** Utility to assist with generation of progress reports. Applications build |
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24 | * a hierarchy of {@link Progress} instances, each modelling a phase of |
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25 | * execution. The root is constructed with {@link #Progress()}. Nodes for |
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26 | * sub-phases are created by calling {@link #addPhase()}. |
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27 | */ |
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28 | public class Progress { |
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29 | private String status = ""; |
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30 | private float progress; |
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31 | private int currentPhase; |
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32 | private ArrayList<Progress> phases = new ArrayList<Progress>(); |
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33 | private Progress parent; |
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34 | private float progressPerPhase; |
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35 | |
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36 | /** Creates a new root node. */ |
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37 | public Progress() {} |
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38 | |
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39 | /** Adds a named node to the tree. */ |
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40 | public Progress addPhase(String status) { |
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41 | Progress phase = addPhase(); |
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42 | phase.setStatus(status); |
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43 | return phase; |
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44 | } |
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45 | |
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46 | /** Adds a node to the tree. */ |
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47 | public synchronized Progress addPhase() { |
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48 | Progress phase = new Progress(); |
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49 | phases.add(phase); |
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50 | phase.parent = this; |
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51 | progressPerPhase = 1.0f / (float)phases.size(); |
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52 | return phase; |
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53 | } |
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54 | |
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55 | /** Called during execution to move to the next phase at this level in the |
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56 | * tree. */ |
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57 | public synchronized void startNextPhase() { |
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58 | currentPhase++; |
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59 | } |
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60 | |
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61 | /** Returns the current sub-node executing. */ |
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62 | public synchronized Progress phase() { |
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63 | return phases.get(currentPhase); |
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64 | } |
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65 | |
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66 | /** Completes this node, moving the parent node to its next child. */ |
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67 | public void complete() { |
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68 | // we have to traverse up to our parent, so be careful about locking. |
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69 | Progress myParent; |
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70 | synchronized(this) { |
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71 | progress = 1.0f; |
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72 | myParent = parent; |
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73 | } |
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74 | if (myParent != null) { |
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75 | // this will synchronize on the parent, so we make sure we release |
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76 | // our lock before getting the parent's, since we're traversing |
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77 | // against the normal traversal direction used by get() or toString(). |
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78 | // We don't need transactional semantics, so we're OK doing this. |
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79 | myParent.startNextPhase(); |
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80 | } |
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81 | } |
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82 | |
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83 | /** Called during execution on a leaf node to set its progress. */ |
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84 | public synchronized void set(float progress) { |
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85 | this.progress = progress; |
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86 | } |
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87 | |
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88 | /** Returns the overall progress of the root. */ |
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89 | // this method probably does not need to be synchronized as getINternal() is synchronized |
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90 | // and the node's parent never changes. Still, it doesn't hurt. |
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91 | public synchronized float get() { |
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92 | Progress node = this; |
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93 | while (node.parent != null) { // find the root |
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94 | node = parent; |
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95 | } |
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96 | return node.getInternal(); |
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97 | } |
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98 | |
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99 | /** Computes progress in this node. */ |
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100 | private synchronized float getInternal() { |
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101 | int phaseCount = phases.size(); |
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102 | if (phaseCount != 0) { |
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103 | float subProgress = |
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104 | currentPhase < phaseCount ? phase().getInternal() : 0.0f; |
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105 | return progressPerPhase*(currentPhase + subProgress); |
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106 | } else { |
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107 | return progress; |
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108 | } |
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109 | } |
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110 | |
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111 | public synchronized void setStatus(String status) { |
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112 | this.status = status; |
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113 | } |
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114 | |
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115 | public String toString() { |
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116 | StringBuffer result = new StringBuffer(); |
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117 | toString(result); |
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118 | return result.toString(); |
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119 | } |
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120 | |
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121 | private synchronized void toString(StringBuffer buffer) { |
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122 | buffer.append(status); |
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123 | if (phases.size() != 0 && currentPhase < phases.size()) { |
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124 | buffer.append(" > "); |
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125 | phase().toString(buffer); |
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126 | } |
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127 | } |
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128 | |
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129 | } |
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