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| <html> |
| |
| <head> |
| <meta http-equiv="Content-Language" content="en-us"> |
| <link rel="stylesheet" type="text/css" href="../stylesheets/style.css"> |
| <title>Property Task</title> |
| </head> |
| |
| <body> |
| |
| <h2><a name="property">Property</a></h2> |
| <h3>Description</h3> |
| <p>Sets a <a href="../using.html#properties">property</a> |
| (by name and value), or set of properties (from file or |
| resource) in the project. Properties are case sensitive.</p> |
| Properties are immutable: whoever sets a property first freezes it for the |
| rest of the build; they are most definitely not variables. |
| <p>There are six ways to set properties:</p> |
| <ul> |
| <li>By supplying both the <i>name</i> and <i>value</i> attribute.</li> |
| <li>By supplying both the <i>name</i> and <i>refid</i> attribute.</li> |
| <li>By setting the <i>file</i> attribute with the filename of the property |
| file to load. This property file has the format as defined by the file used |
| in the class java.util.Properties, with the same rules about how |
| non-ISO8859-1 characters must be escaped.</li> |
| <li>By setting the <i>url</i> attribute with the url from which to load the |
| properties. This url must be directed to a file that has the format as defined |
| by the file used in the class java.util.Properties.</li> |
| <li>By setting the <i>resource</i> attribute with the resource name of the |
| property file to load. A resource is a property file on the current |
| classpath, or on the specified classpath.</li> |
| <li>By setting the <i>environment</i> attribute with a prefix to use. |
| Properties will be defined for every environment variable by |
| prefixing the supplied name and a period to the name of the variable.</li> |
| </ul> |
| <p>Although combinations of these ways are possible, only one should be used |
| at a time. Problems might occur with the order in which properties are set, for |
| instance.</p> |
| <p>The value part of the properties being set, might contain references to other |
| properties. These references are resolved at the time these properties are set. |
| This also holds for properties loaded from a property file.</p> |
| <p>A list of predefined properties can be found <a |
| href="../using.html#built-in-props">here</a>.</p> |
| |
| <h4>OpenVMS Users</h4> |
| <p>With the <code>environment</code> attribute this task will load all defined |
| logicals on an OpenVMS system. Logicals with multiple equivalence names get |
| mapped to a property whose value is a comma separated list of all equivalence |
| names. If a logical is defined in multiple tables, only the most local |
| definition is available (the table priority order being PROCESS, JOB, GROUP, |
| SYSTEM). |
| </p> |
| |
| <h3>Parameters</h3> |
| <table border="1" cellpadding="2" cellspacing="0"> |
| <tr> |
| <td valign="top"><b>Attribute</b></td> |
| <td valign="top"><b>Description</b></td> |
| <td align="center" valign="top"><b>Required</b></td> |
| </tr> |
| <tr> |
| <td valign="top">name</td> |
| <td valign="top">the name of the property to set.</td> |
| <td valign="top" align="center">No</td> |
| </tr> |
| <tr> |
| <td valign="top">value</td> |
| <td valign="top">the value of the property.</td> |
| <td valign="middle" align="center" rowspan="3">One of these, when using the |
| name attribute</td> |
| </tr> |
| <tr> |
| <td valign="top">location</td> |
| <td valign="top">Sets the property to the absolute filename of the |
| given file. If the value of this attribute is an absolute path, it |
| is left unchanged (with / and \ characters converted to the |
| current platforms conventions). Otherwise it is taken as a path |
| relative to the project's basedir and expanded.</td> |
| </tr> |
| <tr> |
| <td valign="top">refid</td> |
| <td valign="top"><a href="../using.html#references">Reference</a> to an object |
| defined elsewhere. Only yields reasonable results for references |
| to <a href="../using.html#path">PATH like structures</a> or properties.</td> |
| </tr> |
| <tr> |
| <td valign="top">resource</td> |
| <td valign="top"> the name of the classpath resource containing |
| properties settings in properties file format.</td> |
| <td valign="middle" align="center" rowspan="4">One of these, when |
| <b>not</b> using the name attribute</td> |
| </tr> |
| <tr> |
| <td valign="top">file</td> |
| <td valign="top">the location of the properties file to load.</td> |
| </tr> |
| <tr> |
| <td valign="top">url</td> |
| <td valign="top">a url containing properties-format settings.</td> |
| </tr> |
| <tr> |
| <td valign="top">environment</td> |
| <td valign="top">the prefix to use when retrieving environment variables. Thus |
| if you specify environment="myenv" you will be able to access OS-specific |
| environment variables via property names "myenv.PATH" or |
| "myenv.TERM". Note that if you supply a property name with a final |
| "." it will not be doubled; i.e. environment="myenv." will still |
| allow access of environment variables through "myenv.PATH" and |
| "myenv.TERM". This functionality is currently only implemented |
| on <a href="#notes-env">select platforms</a>. Feel free to send patches to increase the |
| number of platforms on which this functionality is supported ;).<br> |
| Note also that properties are case-sensitive, even if the |
| environment variables on your operating system are not; e.g. Windows 2000's |
| system path variable is set to an Ant property named "env.Path" |
| rather than "env.PATH".</td> |
| </tr> |
| <tr> |
| <td valign="top">classpath</td> |
| <td valign="top">the classpath to use when looking up a resource.</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">classpathref</td> |
| <td valign="top">the classpath to use when looking up a resource, |
| given as <a href="../using.html#references">reference</a> to a <code><path></code> defined |
| elsewhere..</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">prefix</td> |
| <td valign="top">Prefix to apply to properties loaded using <code>file</code>, |
| <code>resource</code>, or <code>url</code>. |
| A "." is appended to the prefix if not specified.</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| </table> |
| <h3>Parameters specified as nested elements</h3> |
| <h4>classpath</h4> |
| <p><code>Property</code>'s <i>classpath</i> attribute is a <a |
| href="../using.html#path">PATH like structure</a> and can also be set via a nested |
| <i>classpath</i> element.</p> |
| <h3>Examples</h3> |
| <pre> <property name="foo.dist" value="dist"/></pre> |
| <p>sets the property <code>foo.dist</code> to the value "dist".</p> |
| <pre> <property file="foo.properties"/></pre> |
| <p>reads a set of properties from a file called "foo.properties".</p> |
| <pre> <property url="http://www.mysite.com/bla/props/foo.properties"/></pre> |
| <p>reads a set of properties from the address "http://www.mysite.com/bla/props/foo.properties".</p> |
| <pre> <property resource="foo.properties"/></pre> |
| <p>reads a set of properties from a resource called "foo.properties".</p> |
| <p>Note that you can reference a global properties file for all of your Ant |
| builds using the following:</p> |
| <pre> <property file="${user.home}/.ant-global.properties"/></pre> |
| <p>since the "user.home" property is defined by the Java virtual machine |
| to be your home directory. Where the "user.home" property resolves to in |
| the file system depends on the operating system version and the JVM implementation. |
| On Unix based systems, this will map to the user's home directory. On modern Windows |
| variants, this will most likely resolve to the user's directory in the "Documents |
| and Settings" folder. Older windows variants such as Windows 98/ME are less |
| predictable, as are other operating system/JVM combinations.</p> |
| |
| <pre> |
| <property environment="env"/> |
| <echo message="Number of Processors = ${env.NUMBER_OF_PROCESSORS}"/> |
| <echo message="ANT_HOME is set to = ${env.ANT_HOME}"/> |
| </pre> |
| <p>reads the system environment variables and stores them in properties, prefixed with "env". |
| Note that this only works on <em>select</em> operating systems. |
| Two of the values are shown being echoed. |
| </p> |
| |
| <h3>Property Files</h3> |
| |
| As stated, this task will load in a properties file stored in the file |
| system, or as a resource on a classpath. Here are some interesting facts |
| about this feature |
| <ol> |
| <li>If the file is not there, nothing is printed except at -verbose log |
| level. This lets you have optional configuration files for every |
| project, that team members can customize. |
| <li>The rules for this format are laid down |
| <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/util/Properties.html#load(java.io.InputStream)">by Sun</a>. |
| This makes it hard for Team Ant to field bug reports about it. |
| <li>Trailing spaces are not stripped. It may have been what you wanted. |
| <li>Want unusual characters? Escape them \u0456 or \" style. |
| <li>Ant Properties are expanded in the file. |
| </ol> |
| In-file property expansion is very cool. Learn to use it. |
| <p> |
| Example: |
| <pre> |
| build.compiler=jikes |
| deploy.server=lucky |
| deploy.port=8080 |
| deploy.url=http://${deploy.server}:${deploy.port}/ |
| </pre> |
| |
| |
| <a name="notes-env"></a> |
| <h3>Notes about environment variables</h3> |
| <p> |
| Ant runs on Java 1.2 therefore it cant use Java5 features for accessing environment |
| variables. So it starts a command in a new process which prints the environment variables, |
| analyzes the output and creates the properties. <br> |
| There are commands for the following operating systems implemented in |
| <a href="http://svn.apache.org/viewvc/ant/core/trunk/src/main/org/apache/tools/ant/taskdefs/Execute.java?view=markup"> |
| Execute.java</a> (method <tt>getProcEnvCommand()</tt>): |
| <table> |
| <tr> |
| <th>OS</th> |
| <th>command</th> |
| </tr> |
| <tr> |
| <td> os/2 </td> |
| <td> cmd /c set </td> |
| </tr> |
| <tr> |
| <td colspan="2"> windows </td> |
| </tr> |
| <tr> |
| <td> * win9x </td> |
| <td> command.com /c set </td> |
| </tr> |
| <tr> |
| <td> * other </td> |
| <td> cmd /c set </td> |
| </tr> |
| <tr> |
| <td> z/os </td> |
| <td> /bin/env <b>OR</b> /usr/bin/env <b>OR</b> env <i>(depending on read rights)</i> </td> |
| </tr> |
| <tr> |
| <td> unix </td> |
| <td> /bin/env <b>OR</b> /usr/bin/env <b>OR</b> env <i>(depending on read rights)</i> </td> |
| </tr> |
| <tr> |
| <td> netware </td> |
| <td> env </td> |
| </tr> |
| <tr> |
| <td> os/400 </td> |
| <td> env </td> |
| </tr> |
| <tr> |
| <td> openvms </td> |
| <td> show logical </td> |
| </tr> |
| </table> |
| </p> |
| |
| </body> |
| </html> |
