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<h1>Java API bindings</h1>
<h2>Presentation</h2>
<p>The Java bindings make use of <a href="https://jna.dev.java.net/">JNA</a>
to expose the C API in a Java friendly way. The bindings are are based on
work initiated by Toth Istvan.</p>
<h2>Getting it</h2>
<p>
The latest versions of the libvirt Java bindings can be downloaded from:
</p>
<ul>
<li><a href="ftp://libvirt.org/libvirt/java/">libvirt.org FTP server</a></li>
<li><a href="http://libvirt.org/sources/java/">libvirt.org HTTP server</a></li>
</ul>
<h3>Maven</h3>
<p>A maven repository is located at <a href="http://www.libvirt.org/maven2/">http://www.libvirt.org/maven2/</a>
which you can use to include this in your maven projects.</p>
<h2>GIT source repository</h2>
<p> The Java bindings code source is now maintained in a <a
href="http://git-scm.com/">git</a> repository available on
<a href="http://libvirt.org/git/">libvirt.org</a>:
</p>
<pre>
git clone git://libvirt.org/libvirt-java.git
</pre>
<p>
It can also be browsed at
</p>
<pre>
<a href="http://libvirt.org/git/?p=libvirt-java.git;a=summary">http://libvirt.org/git/?p=libvirt-java.git;a=summary</a>
</pre>
<p></p>
<h2>GIT repository mirror</h2>
<p>
The source code is also mirrored on <a href="http://www.gitorious.org">gitorious</a>
to aid in public development. You clone the repo with
</p>
<pre>
git clone git://gitorious.org/libvirt/libvirt-java.git
</pre>
<p>
It can also be browsed at
</p>
<pre>
<a href="http://gitorious.org/libvirt/libvirt-java">http://gitorious.org/libvirt/libvirt-java</a>
</pre>
<p></p>
<h2>CVS repository access (Deprecated)</h2>
<p> The old source repository uses <a
href="http://ximbiot.com/cvs/cvshome/docs/">CVS</a> and anonymous access
is provided. Prior to accessing the server is it necessary to authenticate
using the password <code>anoncvs</code>. This can be accomplished with
the <code>cvs login</code> command:
</p>
<pre>
# cvs -d :pserver:anoncvs@libvirt.org:2401/data/cvs login
</pre>
<p>
Once authenticated, a checkout can be obtained using
</p>
<pre>
# cvs -d :pserver:anoncvs@libvirt.org:2401/data/cvs co libvirt-java
</pre>
<p></p>
<h2>Building</h2>
<p>The code is built using ant, and assumes that you have the jna jar installed. Once you have downloaded
the code you can build the code with</p>
<pre>
% cd libvirt-java
% ant build
</pre>
<h2>Content</h2>
<p>The bindings are articulated around a few
classes in the <code>org/libvirt</code> package, notably the
<code>Connect</code>, <code>Domain</code> and <code>Network</code>
ones. Functions in the <a href="html/libvirt-libvirt.html">C API</a>
taking <code>virConnectPtr</code>, <code>virDomainPtr</code> or
<code>virNetworkPtr</code> as their first argument usually become
methods for the classes, their name is just stripped from the
virConnect or virDomain(Get) prefix and the first letter gets converted to
lower case, for example the C functions:</p>
<p>
<code>int <a href="html/libvirt-libvirt.html#virConnectNumOfDomains">virConnectNumOfDomains</a>
(virConnectPtr conn);</code>
</p>
<p>
<code>int <a href="html/libvirt-libvirt.html#virDomainSetMaxMemory">virDomainSetMaxMemory</a>
(virDomainPtr domain, unsigned long memory);</code>
</p>
<p>become</p>
<p>
<code>virConn.numOfDomains()</code>
</p>
<p>
<code>virDomain.setMaxMemory(long memory)</code>
</p>
<p> There is of course some functions where the mapping is less direct
and using extra classes to map complex arguments. The <a href="http://libvirt.org/sources/java/javadoc">Javadoc</a> is available online or as
part of a separate libvirt-java-javadoc package.</p>
<p>So let's look at a simple example inspired from the
<code>test.java</code> test found in <code>src</code> in the source tree:</p>
<pre>import <span style="color: #0071FF; background-color: #FFFFFF">org.libvirt.*</span>;
public class minitest {
public static void main(String[] args) {
Connect conn=null;
try{
conn = new <span style="color: #0071FF; background-color: #FFFFFF">Connect</span>("test:///default", true);
} catch (<span style="color: #0071FF; background-color: #FFFFFF">LibvirtException</span> e){
System.out.println("exception caught:"+e);
System.out.println(e.getError());
}
try{
<span style="color: #0071FF; background-color: #FFFFFF">Domain</span> testDomain=conn.<span style="color: #007F00; background-color: #FFFFFF">domainLookupByName</span>("test");
System.out.println("Domain:" + testDomain.<span style="color: #E50073; background-color: #FFFFFF">getName</span>() + " id " +
testDomain.<span style="color: #E50073; background-color: #FFFFFF">getID</span>() + " running " +
testDomain.<span style="color: #E50073; background-color: #FFFFFF">getOSType</span>());
} catch (<span style="color: #0071FF; background-color: #FFFFFF">LibvirtException</span> e){
System.out.println("exception caught:"+e);
System.out.println(e.getError());
}
}
}
</pre>
<p>There is not much to comment about it, it really is a straight mapping
from the C API, the only points to notice are:</p>
<ul>
<li>the import of the modules in the <code><span style="color: #0071FF; background-color: #FFFFFF">org.libvirt</span></code> package</li>
<li>getting a connection to the hypervisor, in that case using the
readonly access to the default test hypervisor.</li>
<li>getting an object representing the test domain using <span style="color: #007F00; background-color: #FFFFFF">lookupByName</span></li>
<li>if the domain is not found a LibvirtError exception will be raised</li>
<li>extracting and printing some information about the domain using
various <span style="color: #E50073; background-color: #FFFFFF">methods</span>
associated to the Domain class.</li>
</ul>
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