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| 3 | <head>
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| 4 | <meta http-equiv="Content-Language" content="en-us">
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| 5 | <title>Checksum Task</title>
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| 6 | <link rel="stylesheet" type="text/css" href="../stylesheets/antmanual.css">
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| 7 | </head>
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| 8 |
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| 9 | <body>
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| 10 |
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| 11 | <h2><a name="checksum">Checksum</a></h2>
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| 12 | <h3>Description</h3>
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| 13 | <p>
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| 14 | Generates checksum for files. This task can also be used to
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| 15 | perform checksum verifications.
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| 16 | </p>
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| 17 |
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| 18 | <p>Note that many popular message digest functions - including MD5 and
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| 19 | SHA-1 - have been broken recently. If you are going to use the task
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| 20 | to create checksums used in an environment where security is
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| 21 | important, please take some time to investigate the algorithms offered
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| 22 | by your JCE provider. Note also that some JCE providers like the one
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| 23 | by <a href="http://www.bouncycastle.org/">The Legion of the Bouncy
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| 24 | Castle</a>, the <a href="http://www.gnu.org/software/gnu-crypto/">GNU
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| 25 | project</a> or <a
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| 26 | href="http://jce.iaik.tugraz.at/products/01_jce/index.php">the
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| 27 | Technical University Graz</a> offer more digest algorithms than those
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| 28 | built-in into your JDK.</p>
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| 29 |
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| 30 | <h3>Parameters</h3>
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| 31 | <table border="1" cellpadding="2" cellspacing="0">
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| 32 | <tr>
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| 33 | <td valign="top"><b>Attribute</b></td>
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| 34 | <td valign="top"><b>Description</b></td>
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| 35 | <td align="center" valign="top"><b>Required</b></td>
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| 36 | </tr>
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| 37 | <tr>
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| 38 | <td valign="top">file</td>
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| 39 | <td valign="top">The file to generate checksum for.</td>
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| 40 | <td valign="top" align="center">One of either <var>file</var> or
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| 41 | at least one nested fileset element.</td>
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| 42 | </tr>
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| 43 | <tr>
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| 44 | <td valign="top">todir</td>
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| 45 | <td valign="top">The root directory where checksums should be written.</td>
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| 46 | <td valign="top" align="center">No. If not specified, checksum files
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| 47 | will be written to the same directory as the files themselves.
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| 48 | <em>since Ant 1.6</em>
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| 49 | </td>
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| 50 | </tr>
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| 51 | <tr>
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| 52 | <td valign="top">algorithm</td>
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| 53 | <td valign="top">Specifies the algorithm to be used to
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| 54 | compute the checksum. Defaults to "MD5".
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| 55 | Other popular algorithms like "SHA" may be used
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| 56 | as well.
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| 57 | </td>
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| 58 | <td valign="top" align="center">No</td>
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| 59 | </tr>
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| 60 | <tr>
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| 61 | <td valign="top">provider</td>
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| 62 | <td valign="top">Specifies the provider of the algorithm.</td>
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| 63 | <td valign="top" align="center">No</td>
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| 64 | </tr>
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| 65 | <tr>
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| 66 | <td valign="top">fileext</td>
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| 67 | <td valign="top">The generated checksum file's name will be the
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| 68 | original filename with the fileext added to it.
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| 69 | Defaults to a "." and the algorithm name being used.
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| 70 | </td>
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| 71 | <td valign="top" align="center">No</td>
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| 72 | </tr>
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| 73 | <tr>
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| 74 | <td valign="top">property</td>
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| 75 | <td valign="top">This attribute can mean two different things, it
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| 76 | depends on the presence of the verifyproperty attribute.<br/>
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| 77 | <b>If you don't set the verifyproperty attribute</b>, property
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| 78 | specifies the name of the property to be set with the generated
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| 79 | checksum value.<br/>
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| 80 | <b>If you set the verifyproperty attribute</b>, property specifies
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| 81 | the checksum you expect to be generated (the checksum itself, not
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| 82 | a name of a property containing the checksum).<br/>
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| 83 | This cannot be specified when fileext is being used or when the
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| 84 | number of files for which checksums is to be generated is greater
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| 85 | than 1.
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| 86 | </td>
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| 87 | <td valign="top" align="center">No</td>
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| 88 | </tr>
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| 89 | <tr>
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| 90 | <td valign="top">totalproperty</td>
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| 91 | <td valign="top">If specified, this attribute specifies the name of
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| 92 | the property that will hold a checksum of all the checksums and
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| 93 | file paths. The individual checksums and the relative paths to
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| 94 | the files within the filesets they are defined in will be used to
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| 95 | compute this checksum. (The file separators in the paths will be
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| 96 | converted to '/' before computation to ensure platform portability).
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| 97 | <em>since Ant 1.6</em>
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| 98 | </td>
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| 99 | <td valign="top" align="center">No</td>
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| 100 | </tr>
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| 101 | <tr>
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| 102 | <td valign="top">forceoverwrite</td>
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| 103 | <td valign="top">Overwrite existing files even if the destination
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| 104 | files are newer. Defaults to "no".</td>
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| 105 | <td valign="top" align="center">No</td>
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| 106 | </tr>
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| 107 | <tr>
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| 108 | <td valign="top">verifyproperty</td>
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| 109 | <td valign="top">Specifies the name of the property to be set
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| 110 | with "true" or "false" depending upon whether
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| 111 | the generated checksum matches the existing checksum. When
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| 112 | this is set, the generated checksum is not written to a file or
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| 113 | property, but rather, the content of the file or property is used to
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| 114 | check against the generated checksum.
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| 115 | <td valign="top" align="center">No</td>
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| 116 | </tr>
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| 117 | <tr>
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| 118 | <td valign="top">readbuffersize</td>
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| 119 | <td valign="top">The size of the buffer (in bytes) to use when
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| 120 | reading a file. Defaults to "8192" - you may get a
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| 121 | better performance on big files if you increase this value.</td>
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| 122 | <td valign="top" align="center">No</td>
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| 123 | </tr>
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| 124 | </table>
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| 125 | <h3>Parameters specified as nested elements</h3>
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| 126 |
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| 127 | <h4>fileset</h4>
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| 128 | <p>
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| 129 | <a href="../CoreTypes/fileset.html">FileSets</a> are used to select files to
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| 130 | generate checksums for.
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| 131 | </p>
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| 132 |
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| 133 | <h3>Examples</h3>
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| 134 | <p><b>Example 1</b></p>
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| 135 | <blockquote><pre><checksum file="foo.bar"/></pre></blockquote>
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| 136 | Generates a MD5 checksum for foo.bar and stores the checksum in the destination file
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| 137 | foo.bar.MD5. foo.bar.MD5 is overwritten only if foo.bar is newer than itself.
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| 138 |
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| 139 | <p><b>Example 2</b></p>
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| 140 | <blockquote><pre><checksum file="foo.bar" forceOverwrite="yes"/></pre></blockquote>
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| 141 | Generates a MD5 checksum for foo.bar and stores the checksum in foo.bar.MD5.
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| 142 | If foo.bar.MD5 already exists, it is overwritten.
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| 143 |
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| 144 | <p><b>Example 3</b></p>
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| 145 | <blockquote><pre><checksum file="foo.bar" property="foobarMD5"/></pre></blockquote>
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| 146 | Generates a MD5 checksum for foo.bar and stores it in the Project Property foobarMD5.
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| 147 |
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| 148 | <p><b>Example 4</b></p>
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| 149 | <blockquote><pre><checksum file="foo.bar" verifyProperty="isMD5ok"/></pre></blockquote>
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| 150 | Generates a MD5 checksum for foo.bar, compares it against foo.bar.MD5 and sets
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| 151 | isMD5ok to either true or false, depending upon the result.
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| 152 |
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| 153 | <p><b>Example 5</b></p>
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| 154 | <blockquote><pre><checksum file="foo.bar" algorithm="SHA" fileext="asc"/></pre></blockquote>
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| 155 | Generates a SHA checksum for foo.bar and stores the checksum in the destination file
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| 156 | foo.bar.asc. foo.bar.asc is overwritten only if foo.bar is newer than itself.
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| 157 |
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| 158 | <p><b>Example 6</b></p>
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| 159 | <blockquote><pre>
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| 160 | <checksum file="foo.bar" property="${md5}" verifyProperty="isEqual"/>
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| 161 | </pre></blockquote>
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| 162 | Generates a MD5 checksum for foo.bar, compares it against the value of the property
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| 163 | md5, and sets isEqual to either true or false, depending upon the result.
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| 164 |
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| 165 | <p><b>Example 7</b></p>
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| 166 | <blockquote><pre>
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| 167 | <checksum>
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| 168 | <fileset dir=".">
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| 169 | <include name="foo*"/>
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| 170 | </fileset>
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| 171 | </checksum>
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| 172 | </pre></blockquote>
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| 173 | Works just like Example 1, but generates a .MD5 file for every file that begins with the name foo.
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| 174 |
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| 175 | <p><b>Example 8</b></p>
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| 176 | <blockquote><pre>
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| 177 | <condition property="isChecksumEqual">
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| 178 | <checksum>
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| 179 | <fileset dir=".">
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| 180 | <include name="foo.bar"/>
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| 181 | </fileset>
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| 182 | </checksum>
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| 183 | </condition>
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| 184 | </pre></blockquote>
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| 185 | Works like Example 4, but only sets isChecksumEqual to true, if the
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| 186 | checksum matches - it will never be set to false. This example
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| 187 | demonstrates use with the Condition task.
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| 188 |
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| 189 |
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| 190 | <h3>Note:</h3>
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| 191 | When working with more than one file, if condition and/or verifyproperty is used,
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| 192 | the result will be true only if the checksums matched correctly for all files being
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| 193 | considered.
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| 194 |
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| 195 | <hr><p align="center">Copyright © 2001-2005 The Apache Software Foundation. All rights
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| 196 | Reserved.</p>
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| 197 |
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| 198 | </body>
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| 199 | </html>
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| 200 |
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