docs/java.html.in

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   5     <h1>Java API bindings</h1>
   6
   7 <h2>Presentation</h2>
   8     <p>The Java bindings make use of <a href="https://jna.dev.java.net/">JNA</a>
   9     to expose the C API in a Java friendly way. The bindings are based on
  10     work initiated by Toth Istvan.</p>
  11
  12 <h2>Getting it</h2>
  13 <p>
  14   The latest versions of the libvirt Java bindings can be downloaded from:
  15 </p>
  16
  17 <ul>
  18 <li><a href="ftp://libvirt.org/libvirt/java/">libvirt.org FTP server</a></li>
  19 <li><a href="https://libvirt.org/sources/java/">libvirt.org HTTP server</a></li>
  20 </ul>
  21
  22 <h3>Maven</h3>
  23 <p>A maven repository is located at <a href="https://libvirt.org/maven2/">https://libvirt.org/maven2/</a>
  24 which you can use to include this in your maven projects.</p>
  25
  26 <h2>GIT source repository</h2>
  27 <p> The Java bindings code source is now maintained in a <a
  28 href="http://git-scm.com/">git</a> repository available on
  29 <a href="https://libvirt.org/git/">libvirt.org</a>:
  30 </p>
  31 <pre>
  32 git clone https://libvirt.org/git/libvirt-java.git
  33 </pre>
  34 <p>
  35 It can also be browsed at
  36 </p>
  37 <pre>
  38
  39 <a href="https://libvirt.org/git/?p=libvirt-java.git;a=summary">https://libvirt.org/git/?p=libvirt-java.git;a=summary</a>
  40 </pre>
  41
  42
  43 <h2>Building</h2>
  44 <p>The code is built using ant, and assumes that you have the jna jar installed. Once you have downloaded
  45 the code you can build the code with</p>
  46
  47 <pre>
  48
  49 % cd libvirt-java
  50 % ant build
  51 </pre>
  52
  53
  54 <h2>Content</h2>
  55 <p>The bindings are articulated around a few
  56 classes in the <code>org/libvirt</code> package, notably the
  57 <code>Connect</code>, <code>Domain</code> and <code>Network</code>
  58 ones. Functions in the <a href="html/index.html">C API</a>
  59 taking <code>virConnectPtr</code>, <code>virDomainPtr</code> or
  60 <code>virNetworkPtr</code> as their first argument usually become
  61 methods for the classes, their name is just stripped from the
  62 virConnect or virDomain(Get) prefix and the first letter gets converted to
  63 lower case, for example the C functions:</p>
  64     <p>
  65       <code>int <a href="html/libvirt-libvirt-domain.html#virConnectNumOfDomains">virConnectNumOfDomains</a>
  66 (virConnectPtr conn);</code>
  67     </p>
  68     <p>
  69       <code>int <a href="html/libvirt-libvirt-domain.html#virDomainSetMaxMemory">virDomainSetMaxMemory</a>
  70 (virDomainPtr domain, unsigned long memory);</code>
  71     </p>
  72     <p>become</p>
  73     <p>
  74       <code>virConn.numOfDomains()</code>
  75     </p>
  76     <p>
  77       <code>virDomain.setMaxMemory(long memory)</code>
  78     </p>
  79     <p> There is of course some functions where the mapping is less direct
  80 and using extra classes to map complex arguments. The <a href="https://libvirt.org/sources/java/javadoc">Javadoc</a> is available online or as
  81 part of a separate libvirt-java-javadoc package.</p>
  82     <p>So let's look at a simple example inspired from the
  83 <code>test.java</code> test found in <code>src</code> in the source tree:</p>
  84     <pre>import <span style="color: #0071FF; background-color: #FFFFFF">org.libvirt.*</span>;
  85 public class minitest {
  86     public static void main(String[] args) {
  87         Connect conn=null;
  88         try{
  89             conn = new <span style="color: #0071FF; background-color: #FFFFFF">Connect</span>("test:///default", true);
  90         } catch (<span style="color: #0071FF; background-color: #FFFFFF">LibvirtException</span> e) {
  91             System.out.println("exception caught:"+e);
  92             System.out.println(e.getError());
  93         }
  94         try{
  95             <span style="color: #0071FF; background-color: #FFFFFF">Domain</span> testDomain=conn.<span style="color: #007F00; background-color: #FFFFFF">domainLookupByName</span>("test");
  96             System.out.println("Domain:" + testDomain.<span style="color: #E50073; background-color: #FFFFFF">getName</span>() + " id " +
  97                                testDomain.<span style="color: #E50073; background-color: #FFFFFF">getID</span>() + " running " +
  98                                testDomain.<span style="color: #E50073; background-color: #FFFFFF">getOSType</span>());
  99         } catch (<span style="color: #0071FF; background-color: #FFFFFF">LibvirtException</span> e) {
 100             System.out.println("exception caught:"+e);
 101             System.out.println(e.getError());
 102         }
 103     }
 104 }
 105 </pre>
 106     <p>There is not much to comment about it, it really is a straight mapping
 107 from the C API, the only points to notice are:</p>
 108     <ul>
 109       <li>the import of the modules in the <code><span style="color: #0071FF; background-color: #FFFFFF">org.libvirt</span></code> package</li>
 110       <li>getting a connection to the hypervisor, in that case using the
 111     readonly access to the default test hypervisor.</li>
 112       <li>getting an object representing the test domain using <span style="color: #007F00; background-color: #FFFFFF">lookupByName</span></li>
 113       <li>if the domain is not found a LibvirtError exception will be raised</li>
 114       <li>extracting and printing some information about the domain using
 115     various <span style="color: #E50073; background-color: #FFFFFF">methods</span>
 116     associated to the Domain class.</li>
 117     </ul>
 118 <h2>Maven</h2>
 119   <p>Up until version 0.4.7 the Java bindings were available from the central maven repository.</p>
 120   <p>If you want to use 0.4.8 or higher, please add the following repository to your pom.xml</p>
 121   <pre>&lt;repositories&gt;
 122   &lt;repository&gt;
 123     &lt;id&gt;libvirt-org&lt;/id&gt;
 124     &lt;url&gt;https://libvirt.org/maven2&lt;/url&gt;
 125   &lt;/repository&gt;
 126 &lt;/repositories&gt;</pre>
 127
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