34 lines
6.6 KiB
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34 lines
6.6 KiB
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<title>49. Broadcasting Your Own Events</title><link rel="stylesheet" type="text/css" href="css/manual-multipage.css"><meta name="generator" content="DocBook XSL Stylesheets V1.79.1"><link rel="home" href="multi_spring-cloud.html" title="Spring Cloud"><link rel="up" href="multi__spring_cloud_bus.html" title="Part VII. Spring Cloud Bus"><link rel="prev" href="multi__tracing_bus_events.html" title="48. Tracing Bus Events"><link rel="next" href="multi__spring_cloud_sleuth.html" title="Part VIII. Spring Cloud Sleuth"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">49. Broadcasting Your Own Events</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="multi__tracing_bus_events.html">Prev</a> </td><th width="60%" align="center">Part VII. Spring Cloud Bus</th><td width="20%" align="right"> <a accesskey="n" href="multi__spring_cloud_sleuth.html">Next</a></td></tr></table><hr></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a name="_broadcasting_your_own_events" href="#_broadcasting_your_own_events"></a>49. Broadcasting Your Own Events</h2></div></div></div><p>The Bus can carry any event of type <code class="literal">RemoteApplicationEvent</code>. The default transport is
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JSON, and the deserializer needs to know which types are going to be used ahead of time.
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To register a new type, you must put it in a subpackage of
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<code class="literal">org.springframework.cloud.bus.event</code>.</p><p>To customise the event name, you can use <code class="literal">@JsonTypeName</code> on your custom class or rely on
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the default strategy, which is to use the simple name of the class.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>Both the producer and the consumer need access to the class definition.</p></td></tr></table></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_registering_events_in_custom_packages" href="#_registering_events_in_custom_packages"></a>49.1 Registering events in custom packages</h2></div></div></div><p>If you cannot or do not want to use a subpackage of <code class="literal">org.springframework.cloud.bus.event</code>
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for your custom events, you must specify which packages to scan for events of type
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<code class="literal">RemoteApplicationEvent</code> by using the <code class="literal">@RemoteApplicationEventScan</code> annotation. Packages
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specified with <code class="literal">@RemoteApplicationEventScan</code> include subpackages.</p><p>For example, consider the following custom event, called <code class="literal">MyEvent</code>:</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">package</span> com.acme;
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span> MyEvent <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">extends</span> RemoteApplicationEvent {
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...
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}</pre><p>You can register that event with the deserializer in the following way:</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">package</span> com.acme;
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<em><span class="hl-annotation" style="color: gray">@Configuration</span></em>
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<em><span class="hl-annotation" style="color: gray">@RemoteApplicationEventScan</span></em>
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span> BusConfiguration {
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...
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}</pre><p>Without specifying a value, the package of the class where <code class="literal">@RemoteApplicationEventScan</code>
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is used is registered. In this example, <code class="literal">com.acme</code> is registered by using the package of
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<code class="literal">BusConfiguration</code>.</p><p>You can also explicitly specify the packages to scan by using the <code class="literal">value</code>, <code class="literal">basePackages</code>
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or <code class="literal">basePackageClasses</code> properties on <code class="literal">@RemoteApplicationEventScan</code>, as shown in the
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following example:</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">package</span> com.acme;
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<em><span class="hl-annotation" style="color: gray">@Configuration</span></em>
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">//@RemoteApplicationEventScan({"com.acme", "foo.bar"})</span>
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">//@RemoteApplicationEventScan(basePackages = {"com.acme", "foo.bar", "fizz.buzz"})</span>
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<em><span class="hl-annotation" style="color: gray">@RemoteApplicationEventScan(basePackageClasses = BusConfiguration.class)</span></em>
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span> BusConfiguration {
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...
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}</pre><p>All of the preceding examples of <code class="literal">@RemoteApplicationEventScan</code> are equivalent, in that the
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<code class="literal">com.acme</code> package is registered by explicitly specifying the packages on
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<code class="literal">@RemoteApplicationEventScan</code>.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>You can specify multiple base packages to scan.</p></td></tr></table></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="multi__tracing_bus_events.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="multi__spring_cloud_bus.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="multi__spring_cloud_sleuth.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">48. Tracing Bus Events </td><td width="20%" align="center"><a accesskey="h" href="multi_spring-cloud.html">Home</a></td><td width="40%" align="right" valign="top"> Part VIII. Spring Cloud Sleuth</td></tr></table></div></body></html> |