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, * |
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13 | * software distributed under the License is distributed on an * |
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14 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * |
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15 | * KIND, either express or implied. See the License for the * |
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16 | * specific language governing permissions and limitations * |
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17 | * under the License. * |
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18 | ****************************************************************/ |
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19 | |
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20 | package org.apache.james.mime4j.dom; |
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21 | |
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22 | import java.io.IOException; |
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23 | import java.io.InputStream; |
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24 | import java.io.OutputStream; |
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25 | |
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26 | /** |
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27 | * Abstract implementation of a single message body; that is, a body that does |
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28 | * not contain (directly or indirectly) any other child bodies. It also provides |
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29 | * the parent functionality required by bodies. |
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30 | */ |
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31 | public abstract class SingleBody implements Body { |
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32 | |
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33 | private Entity parent = null; |
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34 | |
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35 | /** |
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36 | * Sole constructor. |
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37 | */ |
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38 | protected SingleBody() { |
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39 | } |
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40 | |
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41 | /** |
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42 | * @see org.apache.james.mime4j.dom.Body#getParent() |
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43 | */ |
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44 | public Entity getParent() { |
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45 | return parent; |
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46 | } |
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47 | |
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48 | /** |
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49 | * @see org.apache.james.mime4j.dom.Body#setParent(org.apache.james.mime4j.dom.Entity) |
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50 | */ |
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51 | public void setParent(Entity parent) { |
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52 | this.parent = parent; |
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53 | } |
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54 | |
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55 | /** |
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56 | * Gets a <code>InputStream</code> which reads the bytes of the body. |
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57 | * |
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58 | * @return the stream, transfer decoded |
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59 | * @throws IOException |
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60 | * on I/O errors. |
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61 | */ |
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62 | public abstract InputStream getInputStream() throws IOException; |
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63 | |
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64 | /** |
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65 | * Writes this single body to the given stream. The default implementation copies |
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66 | * the input stream obtained by {@link #getInputStream()} to the specified output |
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67 | * stream. May be overwritten by a subclass to improve performance. |
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68 | * |
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69 | * @param out |
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70 | * the stream to write to. |
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71 | * @throws IOException |
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72 | * in case of an I/O error |
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73 | */ |
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74 | public void writeTo(OutputStream out) throws IOException { |
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75 | if (out == null) |
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76 | throw new IllegalArgumentException(); |
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77 | |
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78 | InputStream in = getInputStream(); |
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79 | SingleBody.copy(in, out); |
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80 | in.close(); |
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81 | } |
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82 | |
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83 | /** |
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84 | * Returns a copy of this <code>SingleBody</code> (optional operation). |
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85 | * <p> |
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86 | * The general contract of this method is as follows: |
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87 | * <ul> |
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88 | * <li>Invoking {@link #getParent()} on the copy returns <code>null</code>. |
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89 | * That means that the copy is detached from the parent entity of this |
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90 | * <code>SingleBody</code>. The copy may get attached to a different |
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91 | * entity later on.</li> |
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92 | * <li>The underlying content does not have to be copied. Instead it may be |
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93 | * shared between multiple copies of a <code>SingleBody</code>.</li> |
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94 | * <li>If the underlying content is shared by multiple copies the |
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95 | * implementation has to make sure that the content gets deleted when the |
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96 | * last copy gets disposed of (and not before that).</li> |
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97 | * </ul> |
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98 | * <p> |
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99 | * This implementation always throws an |
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100 | * <code>UnsupportedOperationException</code>. |
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101 | * |
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102 | * @return a copy of this <code>SingleBody</code>. |
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103 | * @throws UnsupportedOperationException |
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104 | * if the <code>copy</code> operation is not supported by this |
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105 | * single body. |
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106 | */ |
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107 | public SingleBody copy() { |
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108 | throw new UnsupportedOperationException(); |
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109 | } |
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110 | |
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111 | /** |
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112 | * Subclasses should override this method if they have allocated resources |
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113 | * that need to be freed explicitly (e.g. cannot be simply reclaimed by the |
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114 | * garbage collector). |
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115 | * |
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116 | * The default implementation of this method does nothing. |
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117 | * |
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118 | * @see org.apache.james.mime4j.dom.Disposable#dispose() |
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119 | */ |
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120 | public void dispose() { |
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121 | } |
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122 | |
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123 | static final int DEFAULT_ENCODING_BUFFER_SIZE = 1024; |
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124 | |
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125 | /** |
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126 | * Copies the contents of one stream to the other. |
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127 | * @param in not null |
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128 | * @param out not null |
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129 | * @throws IOException |
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130 | */ |
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131 | private static void copy(final InputStream in, final OutputStream out) throws IOException { |
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132 | final byte[] buffer = new byte[DEFAULT_ENCODING_BUFFER_SIZE]; |
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133 | int inputLength; |
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134 | while (-1 != (inputLength = in.read(buffer))) { |
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135 | out.write(buffer, 0, inputLength); |
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136 | } |
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137 | } |
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138 | |
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139 | } |
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