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<title>Echoproperties Task</title>
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<h2><a name="echoproperties">echoproperties</a></h2>
<h3>Description</h3>

<p>Displays all the current properties (or a subset of them specified
by a nested <code>&lt;propertyset&gt;</code>) in the project.  The
output can be sent to a file if desired.  This task can be used as a
somewhat contrived means of returning data from an
<tt>&lt;ant&gt;</tt> invocation, but is really for debugging build
files.</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">destfile</td>
    <td valign="top">If specified, the value indicates the name of the
    file to send the output of the statement to.  The generated output file
    is compatible for loading by any Java application as a property file.
    If not specified, then the output will go to the Apache Ant log.</td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">prefix</td>
    <td valign="top">
        a prefix which is used to filter the properties
        only those properties starting with this prefix will be echoed.
        <P>
    </td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">regex</td>
    <td valign="top">
        a regular expression which is used to filter the
        properties
        only those properties whose names match it will be echoed.
    </td>
    <td valign="top" align="center">No</td>
  </tr>   
  <tr>
    <td valign="top">failonerror</td>
    <td valign="top">By default, the "failonerror" attribute is enabled.
    If an error occurs while writing the properties to a file, and this
    attribute is enabled, then a BuildException will be thrown, causing the
    build to fail.  If disabled, then IO errors will be reported as a log
    statement, and the build will continue without failure from this task.</td>
    <td valign="top" align="center">No</td>
  </tr>
  <tr>
    <td valign="top">format</td>
    <td valign="top">One of <code>text</code> or <code>xml</code>.
    Determines the output format.  Defaults to <code>text</code>.</td>
    <td valign="top" align="center">No</td>
  </tr>
</table>

<h3>Parameters specified as nested elements</h3>

<h4>propertyset</h4>

<p>You can specify subsets of properties to be echoed with <a
href="../Types/propertyset.html">propertyset</a>s. Using
<tt>propertyset</tt>s gives more control on which properties will be
picked up. The attributes <tt>prefix</tt> and <tt>regex</tt> are just
shorcuts that use <tt>propertyset</tt>s internally.
</p>

<p><em>since Ant 1.6</em>.</p>

<h3>Examples</h3>
<blockquote><pre>
  &lt;echoproperties/&gt;
</pre></blockquote>
<p>Report the current properties to the log.</p>
<blockquote><pre>
  &lt;echoproperties destfile="my.properties"/&gt;
</pre></blockquote>
<p>Report the current properties to the file "my.properties", and will
fail the build if the file could not be created or written to.</p>
<blockquote><pre>
  &lt;echoproperties destfile="my.properties" failonerror="false"/&gt;
</pre></blockquote>
<p>Report the current properties to the file "my.properties", and will
log a message if the file could not be created or written to, but will still
allow the build to continue.</p>
<blockquote><pre>
  &lt;echoproperties prefix="java."/&gt;
</pre></blockquote>
<p>List all properties beginning with "java."</p>
<blockquote><pre>
  &lt;echoproperties&gt;
    &lt;propertyset&gt;
      &lt;propertyref prefix="java."/&gt;
    &lt;/propertyset&gt;
  &lt;/echoproperties&gt;
</pre></blockquote>
<p>This again lists all properties beginning with "java." using a nested
<tt>&lt;/propertyset&gt;</tt> which is an equivalent but longer way.</p>
<blockquote><pre>
  &lt;echoproperties regex=".*ant.*"/&gt;
</pre></blockquote>
<p>Lists all properties that contain "ant" in their names.
The equivalent snippet with <tt>&lt;/propertyset&gt;</tt> is:</p>
<blockquote><pre>
  &lt;echoproperties&gt;
    &lt;propertyset&gt;
      &lt;propertyref regex=".*ant.*"/&gt;
    &lt;/propertyset&gt;
  &lt;/echoproperties&gt;
</pre></blockquote>


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