1 | /*
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2 | * Copyright 2002,2004 The Apache Software Foundation
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3 | *
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4 | * Licensed under the Apache License, Version 2.0 (the "License");
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5 | * you may not use this file except in compliance with the License.
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6 | * You may obtain a copy of the License at
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7 | *
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8 | * http://www.apache.org/licenses/LICENSE-2.0
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9 | *
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10 | * Unless required by applicable law or agreed to in writing, software
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11 | * distributed under the License is distributed on an "AS IS" BASIS,
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12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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13 | * See the License for the specific language governing permissions and
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14 | * limitations under the License.
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15 | *
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16 | */
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17 | package org.apache.tools.ant.filters;
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18 |
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19 | import java.io.IOException;
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20 | import java.io.Reader;
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21 | import org.apache.tools.ant.Project;
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22 |
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23 | /**
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24 | * Expands Ant properties, if any, in the data.
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25 | * <p>
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26 | * Example:<br>
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27 | * <pre><expandproperties/></pre>
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28 | * Or:
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29 | * <pre><filterreader
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30 | * classname="org.apache.tools.ant.filters.ExpandProperties"/></pre>
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31 | *
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32 | */
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33 | public final class ExpandProperties
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34 | extends BaseFilterReader
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35 | implements ChainableReader {
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36 | /** Data that must be read from, if not null. */
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37 | private String queuedData = null;
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38 |
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39 | /**
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40 | * Constructor for "dummy" instances.
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41 | *
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42 | * @see BaseFilterReader#BaseFilterReader()
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43 | */
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44 | public ExpandProperties() {
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45 | super();
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46 | }
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47 |
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48 | /**
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49 | * Creates a new filtered reader.
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50 | *
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51 | * @param in A Reader object providing the underlying stream.
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52 | * Must not be <code>null</code>.
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53 | */
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54 | public ExpandProperties(final Reader in) {
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55 | super(in);
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56 | }
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57 |
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58 | /**
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59 | * Returns the next character in the filtered stream. The original
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60 | * stream is first read in fully, and the Ant properties are expanded.
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61 | * The results of this expansion are then queued so they can be read
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62 | * character-by-character.
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63 | *
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64 | * @return the next character in the resulting stream, or -1
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65 | * if the end of the resulting stream has been reached
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66 | *
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67 | * @exception IOException if the underlying stream throws an IOException
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68 | * during reading
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69 | */
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70 | public final int read() throws IOException {
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71 |
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72 | int ch = -1;
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73 |
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74 | if (queuedData != null && queuedData.length() == 0) {
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75 | queuedData = null;
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76 | }
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77 |
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78 | if (queuedData != null) {
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79 | ch = queuedData.charAt(0);
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80 | queuedData = queuedData.substring(1);
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81 | if (queuedData.length() == 0) {
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82 | queuedData = null;
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83 | }
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84 | } else {
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85 | queuedData = readFully();
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86 | if (queuedData == null) {
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87 | ch = -1;
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88 | } else {
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89 | Project project = getProject();
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90 | queuedData = project.replaceProperties(queuedData);
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91 | return read();
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92 | }
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93 | }
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94 | return ch;
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95 | }
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96 |
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97 | /**
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98 | * Creates a new ExpandProperties filter using the passed in
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99 | * Reader for instantiation.
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100 | *
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101 | * @param rdr A Reader object providing the underlying stream.
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102 | * Must not be <code>null</code>.
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103 | *
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104 | * @return a new filter based on this configuration, but filtering
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105 | * the specified reader
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106 | */
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107 | public final Reader chain(final Reader rdr) {
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108 | ExpandProperties newFilter = new ExpandProperties(rdr);
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109 | newFilter.setProject(getProject());
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110 | return newFilter;
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111 | }
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112 | }
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