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This commit is contained in:
Mark Fisher
2011-02-05 19:14:08 -05:00
parent b6f2f920c8
commit d7e7fd7348
1 changed files with 36 additions and 38 deletions
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74
docs/src/reference/docbook/groovy.xml
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@@ -79,59 +79,57 @@
<para>
You already know that by default, 'payload' and 'headers' will be bound as Groovy binding variables.
However, some times in order to take the most out of Groovy you may want to customize Groovy bindings
(e.g., include extra variables pointing to some scalar values or bind some beans as variables etc.)
To support this requirement we have defined a simple strategy ScriptVariableGenerator.
(e.g., include extra variables pointing to some scalar values or bind some beans as variables).
To support this requirement we have defined a simple strategy: ScriptVariableGenerator.
<programlisting language="java"><![CDATA[public interface ScriptVariableGenerator {
Map<String, Object> generateScriptVariables(Message<?> message);
}]]></programlisting>
As you can see the only method that needs to be implemented is <code>generateScriptVariables(Message)</code> which takes
Message as an argument (allowing you to use data available in Message payload/headers) and returns the Map of variables
that will be bound as Groovy bindings. This method will be called every time the script is executed. We also provide
default implementation and namespace based configuration for simple bindings via &lt;variable&gt; sub-element (see below):
As you can see the only method to implement is <code>generateScriptVariables(Message)</code>. It takes the Message
as an argument. That allows you to use data available in the Message payload and/or headers. The return value is
the Map of variables that will be bound to the script's evaluation context. This method will be called every time
the script is executed, corresponding to the processing of that particular Message. We also provide a
default implementation and namespace based configuration for simple bindings via &lt;variable&gt; sub-elements (see below):
<programlisting language="xml"><![CDATA[<groovy:script location="foo/bar/MyScript.groovy">
<groovy:variable name="foo" value="foo"/>
<groovy:variable name="bar" value="bar"/>
<groovy:variable name="date" ref="date"/>
</groovy:script>]]></programlisting>
As you can see similar to other constructs in Spring, when setting binding variables you can either set scalar values
or reference another bean in the Application Context.
As you can see similar to other constructs in Spring, when binding each of these variables you can either provide a
scalar value or reference another bean in the Application Context.
</para>
<para>
However if you need more dynamics with regard to how a particular variable is generated then all you need to do is
provide your own implementation of ScriptVariableGenerator and inject it via <code>script-variable-generator</code> attribute:
If you need more control over how a particular variable is generated, then all you need to do is
provide your own implementation of ScriptVariableGenerator and reference it with the <code>script-variable-generator</code>
attribute:
<programlisting language="xml"><![CDATA[<groovy:script location="foo/bar/MyScript.groovy"
script-variable-generator="scriptVarGenerator"/>
<bean id="scriptVariableGenerator" class="foo.bar.MyScriptVariableGenerator"/>]]></programlisting>
script-variable-generator="variableGenerator"/>
<bean id="variableGenerator" class="foo.bar.MyScriptVariableGenerator"/>]]></programlisting>
<important>
Remember that <code>script-variable-generator</code> and use of &lt;variable&gt; sub-element is mutually exclusive.
You can only use one of another. Also, the <code>script-variable-generator</code> and/or &lt;variable&gt; sub-elements can
not be used when using inline script, only when pointing to the script via <code>location</code> attribute.
The <code>script-variable-generator</code> attribute and &lt;variable&gt; sub-element(s) are mutually exclusive.
You can use at most one of them. Also, the <code>script-variable-generator</code> and &lt;variable&gt; sub-elements
cannot be used with an inline script, but rather only when pointing to the script via the <code>location</code> attribute.
</important>
If you need control over customization of the Groovy object itself which goes beyond setting variables
(e.g., properties, MetaObject etc.) you can also register a GroovyObjectCustomizer which is an implementation of
<code>org.springframework.scripting.groovy.GroovyObjectCustomizer</code> via <code>customizer</code> attribute.
If you need to customize the Groovy object itself, beyond setting variables, you can reference
a bean that implementats <code>org.springframework.scripting.groovy.GroovyObjectCustomizer</code> via the
<code>customizer</code> attribute. For example, this might be useful if you want to configure a domain-specific
language (DSL) by modifying the MetaClass and registering functions to be available within the script.
<programlisting language="xml"><![CDATA[<service-activator input-channel="withScriptVariableGenerator">
<groovy:script location="org/springframework/integration/groovy/config/GroovyServiceActivatorTests.groovy"
script-variable-generator="scriptVarSource" customizer="groovyCustomizer"/>
<programlisting language="xml"><![CDATA[<service-activator input-channel="groovyChannel">
<groovy:script location="foo/SomeScript.groovy" customizer="groovyCustomizer"/>
</service-activator>
<beans:bean id="groovyCustomizer"
class="ofoo.bar.MyGroovyCustomizer"/>]]></programlisting>
Setting custom GroovyObjectCustomizer is NOT mutually exclusive to &lt;variable&gt; sub-element and/or <code>script-variable-generator</code>
and is allowed with inline scripting.
<beans:bean id="groovyCustomizer" class="org.foo.MyGroovyObjectCustomizer"/>]]></programlisting>
Setting a custom GroovyObjectCustomizer is not mutually exclusive with &lt;variable&gt; sub-elements or
the <code>script-variable-generator</code> attribute. It can also be provided when defining an inline script.
</para>
</section>
@@ -144,13 +142,13 @@ Setting custom GroovyObjectCustomizer is NOT mutually exclusive to &lt;variable&
monitoring and managing the components within the framework as is used for
"application-level" messaging. In Spring Integration we build upon the
adapters described above so that it's possible to send Messages as a means
of invoking exposed operations.
of invoking exposed operations. One option for those operations is Groovy scripts.
<programlisting language="xml"> &lt;groovy:control-bus input-channel="operationChannel"/&gt;</programlisting></para>
<para>The Control Bus has an input channel that can be accessed for
invoking operations on the beans in the application context.</para>
<para>The groovy control bus executes messages on the input channel as
<para>The Groovy Control Bus executes messages on the input channel as
Groovy scripts. It takes a message, compiles the body to a Script,
customizes it with a GroovyObjectCustomizer, and then executes it. The
Control Bus' customizer exposes all the beans in the application context
@@ -159,15 +157,15 @@ Setting custom GroovyObjectCustomizer is NOT mutually exclusive to &lt;variable&
(e.g. several of the TaskExecutor and TaskScheduler implementations).</para>
<para>
If you need control over customization of the Groovy object itself which goes beyond setting variables
(e.g., properties, MetaObject etc.) you can also register a GroovyObjectCustomizer which is an implementation of
<code>org.springframework.scripting.groovy.GroovyObjectCustomizer</code> via <code>customizer</code> attribute.
If you need to further customize the Groovy objects, you can also provide a reference to a bean
that implements <code>org.springframework.scripting.groovy.GroovyObjectCustomizer</code> via
the <code>customizer</code> attribute.
<programlisting language="xml"><![CDATA[<groovy:control-bus input-channel="input" output-channel="output" send-timeout="100" order="1" auto-startup="true"
customizer="groovyCustomizer"/>
<programlisting language="xml"><![CDATA[<groovy:control-bus input-channel="input"
output-channel="output"
customizer="groovyCustomizer"/>
<beans:bean id="groovyCustomizer"
class="ofoo.bar.MyGroovyCustomizer"/>]]></programlisting>
<beans:bean id="groovyCustomizer" class="org.foo.MyGroovyObjectCustomizer"/>]]></programlisting>
</para>
</section>
</section>