wangwei
/
antliscence
forked from youys/ant

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<title>Libraries Task</title>
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<h2><a name="echo">Libraries</a></h2>
<h3>Description</h3>
<p>

    Extensible library download mechanism, integrated with the
    <a href="http://maven.apache.org/">Maven</a> repository hosted
    at ibiblio.org.
   
</p>

<p>
    This task can:
</p>
    <ol>
    <li>Download publicly published JAR files by version.</li>
    <li>Download JAR files from private file: or http: repositories</li>
    <li>Cache the JAR files in a directory tree</li>
    <li>Check for updates on a regular schedule</li>
    <li>Build paths for compilation/execution.</li>
    <li>Fail the build if needed libraries are missing</li>
    <li>Force an update of all libraries</li>
    <li>Skip all downloading when offline
    </ol>

<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">destDir</td>
    <td valign="top">Destination directory for all downloads
    </td>
    <td valign="top" align="center">Yes</td>
  </tr>
  <tr>
    <td valign="top">offline</td>
    <td valign="top">Flag to indicate that the system is offline, and that
    no downloads should take place.
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">flatten</td>
    <td valign="top">flag to indicate that files should be flattened when downloaded
    </td>
    <td valign="top" align="center">No -default false</td>
  </tr>
  <tr>
    <td valign="top">pathID</td>
    <td valign="top">Name of a path to create containing all
    libraries in this declaration.
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">repositoryRef</td>
    <td valign="top">Reference to a predefined repository
    </td>
    <td valign="top" align="center">Only if no repository is defined inline</td>
  </tr>
</table>

 
</table>
<h3>Nested Elements</h3>


<h4>library</h4>
This is the core of the system; a library to (potentially) download.

<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">project</td>
    <td valign="top">Name of the project
    </td>
    <td valign="top" align="center">Yes</td>
  </tr>
  <tr>
    <td valign="top">version</td>
    <td valign="top">
    </td>
    <td valign="top" align="center">Yes</td>
  </tr>
  <tr>
    <td valign="top">archive</td>
    <td valign="top">Name of the archive 
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">destinationName</td>
    <td valign="top">Filename of downloaded file
    </td>
    <td valign="top" align="center">No, default remote name</td>
  </tr>

  <tr>
    <td valign="top">suffix</td>
    <td valign="top">Suffix of the archive
    </td>
    <td valign="top" align="center">No -default ".jar"</td>
  </tr>  
  <tr>
    <td valign="top">enabled</td>
    <td valign="top">flag to turn on or off specific download/use
    of an archive
    </td>
    <td valign="top" align="center">No -default "true"</td>
  </tr>
</table>

<h4>Repository</h4>

A repository is Ant datatype that extends the <code>Repository</code> type.
Ant only ships with one: the mavenrepository;  

<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">url</td>
    <td valign="top">URL of the repository
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top"></td>
    <td valign="top">
    </td>
    <td valign="top" align="center">No</td>
  </tr>
</table>
  
<p>Example:</p>
<pre>
    &lt;repository ref=&quot;predefined.repository&quot; /&gt;
</pre>    

<h4>mavenrepository</h4>

<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">url</td>
    <td valign="top">URL of the repository
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">checkMD5</td>
    <td valign="top">Flag to turn on MD5 checking
    (unimplemented)
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">username</td>
    <td valign="top">HTTP authentication username
    </td>
    <td valign="top" align="center">No</td>
  </tr>  
  <tr>
    <td valign="top">password</td>
    <td valign="top">HTTP authentication password
    </td>
    <td valign="top" align="center">Only if username is set</td>
  </tr>  
</table>

<h3>UpdatePolicies</h3>

<P>Update policies are an (extensible) means of tuning the download, running
code before and possibly after a download. They can enable or disable
checks for individual files, skip the download process, or perform some
post-download validation. 
</P>

<P>All policies have at least the common set of attributes; some may have more,
in which case an updated attribute list is shown. </P>

<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">enabled</td>
    <td valign="top">Enabled flag
    </td>
    <td valign="top" align="center">No -default "true"</td>
  </tr>
</table>

<P>Policies can be chained by listing them in order. Before an update/download 
takes place, all policies will be executed in order. After the download, the
policies will be invoked in reverse order. The compound policy in such a
situation is left to the experimentor, though reading the source will help.
</P>

<p>
Developers may add new polices (such
as signing incoming files) by adding new datatypes extending the
<code>LibraryPolicy</code> class. </P>

<h4>noupdate</h4>

<P>This policy will disable remote downloads when enabled. It is the policy
equivalent of the offline flag.</P>


<p>Example:</p>
<pre>
    &lt;noupdate  /&gt;
</pre> 

<h4>forceupdate</h4>

<P>This policy forces all libraries to be downloaded. If any download failed,
the build will halt.</P>
<p>Example:</p>
<pre>
    &lt;forceupdate  /&gt;
</pre> 

<h4>timestamp</h4>

<P>This policy tells Ant to check the repository to see if the files have changed
using timestamp checks. Any files which are up to date will not be downloaded again. </P>

<p>Example:</p>
<pre>
    &lt;timestamp  /&gt;
</pre> 

<h4>scheduledupdate</h4>

This policy tells Ant to check the repository to see if the files have changed,
but only intermittently. An interval of the size of the schedule has to have
passed, or the set of files to check has to have changed. 

<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">enabled</td>
    <td valign="top">Enabled flag
    </td>
    <td valign="top" align="center">No -default "true"</td>
  </tr>
  <tr>
    <td valign="top">markerFile</td>
    <td valign="top">Name of a file to cache download history
    </td>
    <td valign="top" align="center">Yes</td>
  </tr>
  <tr>
    <td valign="top">Days</td>
    <td valign="top">number of days between update checks
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">Hours</td>
    <td valign="top">number of hours between update checks
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">Minutes</td>
    <td valign="top">number of minutes between update checks
    </td>
    <td valign="top" align="center">No</td>
  </tr>
</table>

<p>Example:</p>
<pre>
    &lt;scheduledupdate days="1" hours="3" minutes="17"  /&gt;
</pre> 

<P>Check for an update every 27 hours, 17 minutes. </P>


<h4>assertdownloaded</h4>

<P>This policy is really for testing the library. It does not
alter the download policy, but after any download has taken place,
it verifies that the number of files downloaded matches the number
expected.</P>

<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">count</td>
    <td valign="top">number of downloaded files expected.
    </td>
    <td valign="top" align="center">Yes</td>
  </tr>  
  <tr>
    <td valign="top">enabled</td>
    <td valign="top">Enabled flag
    </td>
    <td valign="top" align="center">No -default "true"</td>
  </tr>
</table>

<p>Example:</p>
<pre>
    &lt;assertdownloaded cound="4"  /&gt;
</pre> 

<h3>Examples</h3>
<pre>
    &lt;!--
    versions.properties says
    xdoclet.version=2.0
    commons-logging.version=1.0.3
    commons-collections.version=3.1
    --&gt;
    &lt;property file="versions.properties" /&gt;
    
    &lt;libraries destDir="${lib.dir}" pathid="xdoclet.lib" &gt;
      &lt;mavenrepository /&gt;
      &lt;library project="xdoclet" 
        version="${xdoclet.version}" /&gt;
      &lt;library project="commons-logging"  
        version="${commons-logging.version}" /&gt;
      &lt;library project="commons-collections"  
        version="${commons-collections.version}" /&gt;
    &lt;/libraries&gt;
</pre>

<P>Load in versions from a file, then download the relevant archives. No
update schedule is defined, but a path is created for insertion into a
classpath. This property file driven dependency model is what we recommend
over hard coding versions in a build file. 
</P>
 <PRE>   &lt;libraries destDir="build/lib" offline="${offline}" flatten="true"&gt;
      &lt;mavenrepository url="${private.server}"/&gt;
      &lt;library project="doomed" archive="dead-code"
        suffix=".war"
        destinationName="product.war"
        version="LATEST" 
        /&gt;
      &lt;scheduledupdate markerfile="build/lib/marker.properties"
        hours="11" /&gt;
    &lt;/libraries&gt;
</PRE>

<P>Download doomed/dead-code.LATEST.war from a private repository, save it to
build/lib/product.war with an update schedule of every eleven hours. 
</P>

<p align="center">Copyright &copy; 2005 The Apache Software Foundation. All rights
Reserved.</p>

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