mirror of https://gitee.com/openkylin/ant.git
58 lines
2.3 KiB
HTML
58 lines
2.3 KiB
HTML
<!DOCTYPE html>
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<!--
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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https://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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<html lang="en">
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<head>
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<link rel="stylesheet" type="text/css" href="stylesheets/style.css"/>
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<title>If and Unless on all tasks/nested elements</title>
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</head>
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<body>
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<h1 id="if_and_unless">If And Unless</h1>
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<p><em>Since Ant 1.9.1</em>, it is possible to add <var>if</var> and <var>unless</var> attributes on all tasks and nested elements using special namespaces.</p>
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<p>In order to use this feature you need to add the following namespace declarations</p>
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<pre>
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xmlns:if="ant:if"
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xmlns:unless="ant:unless"</pre>
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<p>The <code>if</code> and <code>unless</code> namespaces support the following 3 conditions:</p>
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<dl>
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<dt><q>true</q></dt><dd>true if the value of the attribute evaluates to true</dd>
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<dt><q>blank</q></dt><dd>true if the value of the attribute is null or empty</dd>
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<dt><q>set</q></dt><dd>true if the specified property is set</dd>
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</dl>
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<pre>
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<project name="tryit"
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xmlns:if="ant:if"
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xmlns:unless="ant:unless">
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<exec executable="java">
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<arg line="-X" if:true="${showextendedparams}"/>
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<arg line="-version" unless:true="${showextendedparams}"/>
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</exec>
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<condition property="onmac">
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<os family="mac"/>
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</condition>
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<echo if:set="onmac">running on MacOS</echo>
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<echo unless:set="onmac">not running on MacOS</echo>
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</project></pre>
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</body>
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</html>
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