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<h3 class="sectionHead"><span class="titlemark">12 </span> <a
id="x36-3800012"></a>Peer to Peer</h3>
<!--l. 923--><p class="noindent" >It is possible to connect two applications together directly without using a bus. D-Bus calls this
a peer-to-peer connection.
</p><!--l. 926--><p class="indent" > The Java implementation provides an alternative to the <span
class="cmtt-12">DBusConnection </span>class, the
<span
class="cmtt-12">DirectConnection</span><span class="footnote-mark"><a
href="dbus-java37.html#fn21x0"><sup class="textsuperscript">21</sup></a></span><a
id="x36-38001f21"></a>
class. This allows you to connect two applications together directly without the need of a
bus.
</p><!--l. 932--><p class="indent" > When using a DirectConnection rather than a DBusConnection most operations are the
same. The only things which differ are how you connect and the operations which depend on a
bus. Since peer connections are only one-to-one there is no destination or source
address to messages. There is also no <span
class="cmtt-12">org.freedesktop.DBus </span>service running on the
bus.
</p>
<h4 class="subsectionHead"><span class="titlemark">12.1 </span> <a
id="x36-3900012.1"></a>Connecting to another application</h4>
<!--l. 940--><p class="noindent" >To connect with a peer connection one of the two applications must be listening on the socket
and the other connecting. Both of these use the same method to instantiate the
<span
class="cmtt-12">DirectConnection </span>but with different addresses. To listen rather than connect you add the
<span
class="cmti-12">“listen=true” </span>parameter to the address. Listening and connecting can be seen in figures <a
href="#x36-3900117">17<!--tex4ht:ref: fig:p2plisten --></a> and
<a
href="#x36-3900218">18<!--tex4ht:ref: fig:p2pconnect --></a> respectively. Listening will block at creating the connection until the other application has
connected.
</p><!--l. 948--><p class="indent" > <span
class="cmtt-12">DirectConnection </span>also provides a <span
class="cmtt-12">createDynamicSession </span>method which generates a
random abstract unix socket address to use.
</p>
<hr class="figure" /><div class="figure"
>
<a
id="x36-3900117"></a>
<div class="center"
>
<!--l. 952--><p class="noindent" >
</p>
<div class="verbatim" id="verbatim-28">
DirectConnection dc = new DirectConnection("unix:path=/tmp/dbus-ABCXYZ,listen=true");
</div>
<!--l. 955--><p class="nopar" ></p></div>
<br /> <div class="caption"
><span class="id">Figure 17: </span><span
class="content">Listening for a peer connection</span></div><!--tex4ht:label?: x36-3900117 -->
</div><hr class="endfigure" />
<hr class="figure" /><div class="figure"
>
<a
id="x36-3900218"></a>
<div class="center"
>
<!--l. 962--><p class="noindent" >
</p>
<div class="verbatim" id="verbatim-29">
DirectConnection dc = new DirectConnection("unix:path=/tmp/dbus-ABCXYZ");
</div>
<!--l. 965--><p class="nopar" ></p></div>
<br /> <div class="caption"
><span class="id">Figure 18: </span><span
class="content">Connecting to a peer connection</span></div><!--tex4ht:label?: x36-3900218 -->
</div><hr class="endfigure" />
<h4 class="subsectionHead"><span class="titlemark">12.2 </span> <a
id="x36-4000012.2"></a>Getting Remote Objects</h4>
<!--l. 973--><p class="noindent" >Getting a remote object is essentially the same as with a bus connection, except that you do
not have to specify a bus name, only an object path. There is also no <span
class="cmtt-12">getPeerRemoteObject</span>
method, since there can only be one peer on this connection.
</p>
<hr class="figure" /><div class="figure"
>
<a
id="x36-4000119"></a>
<div class="center"
>
<!--l. 979--><p class="noindent" >
</p>
<div class="verbatim" id="verbatim-30">
RemoteInterface remote = dc.getRemoteObject("/Path");
 <br />remote.doStuff();
</div>
<!--l. 983--><p class="nopar" ></p></div>
<br /> <div class="caption"
><span class="id">Figure 19: </span><span
class="content">Getting a remote object on a peer connection</span></div><!--tex4ht:label?: x36-4000119 -->
</div><hr class="endfigure" />
<!--l. 989--><p class="indent" > The rest of the API is the same for peer connections as bus connections, ommiting any bus
addresses.
</p>
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