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More updates to the aggregator

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This commit is contained in:
Marius Bogoevici
2008-10-19 01:10:15 +00:00
parent fdd0bef28e
commit d518214736
1 changed files with 120 additions and 12 deletions
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132
spring-integration-reference/src/aggregator-resequencer.xml
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@@ -62,7 +62,7 @@
<para>The Resequencer works in a similar way to the Aggregator, in the
sense that it uses the CORRELATION_ID to store messages in groups, the
difference being that all what the Resequencer does, is to release them
in the order of their SEQUENCE_NUMBER. </para>
in the order of their SEQUENCE_NUMBER.</para>
<para>With respect to that, the user might opt to release all messages
at once (after the whole sequence, according to the SEQUENCE_SIZE, has
@@ -104,14 +104,14 @@
message sequence to aggregate is complete (and grouping them according
to their CORRELATION_ID), and implementing the timeout functionality.
The responsibility of deciding whether the message sequence is complete
is delegated to a <code>CompletionStrategy</code> instance. </para>
is delegated to a <code>CompletionStrategy</code> instance.</para>
<para>A brief highlight of the base
<code>AbstractMessageAggregator</code> (the responsibility of
implementing the aggregateMessages method is left to the
developer):</para>
<programlisting>public abstract class AbstractMessageAggregator extends AbstractMessageBarrierConsumer {
<programlisting language="java">public abstract class AbstractMessageAggregator extends AbstractMessageBarrierConsumer {
private volatile CompletionStrategy completionStrategy
= new SequenceSizeCompletionStrategy();
@@ -126,18 +126,18 @@
implement the <code>aggregateMessages</code> method. However, there are
better suited (which reads, less coupled to the API) solutions for
implementing the aggregation logic, which can be configured easily
either through XML or through annotations. </para>
either through XML or through annotations.</para>
<para><note>
<para>In the interest of code simplicity, and promoting good
<para>In the interest of code simplicity, and promoting best
practices such as low coupling, testability, etc., the preferred way
of implementing the aggregation logic by implementing a POJO, and
of implementing the aggregation logic is by implementing a POJO, and
using the XML or annotation support for setting it up in the
application.</para>
</note>The <code>CompletionStrategy</code> interface is defined as
follows:</para>
<programlisting>public interface CompletionStrategy {
<programlisting language="java">public interface CompletionStrategy {
boolean isComplete(List&lt;Message&lt;?&gt;&gt; messages);
@@ -145,17 +145,125 @@
<para>Spring Integration provides an out-of-the box implementation for
<code>CompletionStrategy</code>, the
<code>SequenceSizeCompletionStrategy</code><code>.</code> This
implementation uses the SEQUENCE_NUMBER and SEQUENCE_SIZE of the
arriving messages for deciding when a message group is complete and
ready to be aggregated.<code></code></para>
<code>SequenceSizeCompletionStrategy</code> This implementation uses the
SEQUENCE_NUMBER and SEQUENCE_SIZE of the arriving messages for deciding
when a message group is complete and ready to be
aggregated.<code></code></para>
</section>
</section>
<section>
<title>Configuration using XML</title>
<para></para>
<section>
<title>Configuring an aggregator through XML</title>
<para>Spring Integration supports the configuration of an aggregator via
XML through the &lt;aggregator/&gt; element. A completely defined sample
on how to define such an element is presented below, as well as
it:</para>
<programlisting>&lt;aggregator id="completelyDefinedAggregator" <co
id="???" />
input-channel="completelyDefinedAggregatorInput" <co id="???" />
output-channel="outputChannel" <co id="???" />
discard-channel="discardChannel" <co id="???" />
ref="aggregatorBean" <co id="???" />
method="add" <co id="???" />
completion-strategy="completionStrategy" <co id="???" />
completion-strategy-method="checkCompleteness" <co id="???" />
timeout="42" <co id="???" />
send-partial-result-on-timeout="true" <co id="???" />
reaper-interval="135" <co id="???" />
tracked-correlation-id-capacity="99" <co id="???" />
send-timeout="86420000" /&gt; <co id="???" /></programlisting>
<calloutlist>
<callout arearefs="???">
<para>The id of the aggregator is
<emphasis>optional</emphasis>.</para>
</callout>
<callout arearefs="???">
<para>The input channel of the aggregator.
<emphasis>Required</emphasis>.</para>
</callout>
<callout arearefs="???">
<para>The channel where the aggregator will send the aggregation
results. <emphasis>Required</emphasis>.</para>
</callout>
<callout arearefs="???">
<para>The channel where the aggregator will send the messages that
timed out (if <code>send-partial-results-on-timeout</code> is
<emphasis>true</emphasis>. <emphasis>Optional</emphasis>.</para>
</callout>
<callout arearefs="???">
<para>A reference to a bean defined in the application context. The
bean must either extend <code>AbstractMessageAggregator</code> or be
a POJO. In the latter case the <code>method</code> attribute must be
defined as well. <emphasis>Required</emphasis>.</para>
</callout>
<callout arearefs="???">
<para>A method defined on the bean referenced by <code>ref</code>,
<emphasis><emphasis>that implements the message aggregation
algorithm.</emphasis> Optional, with restrictions (see
above).</emphasis></para>
</callout>
<callout arearefs="???">
<para>A reference to a bean that implements the decision algorithm
as to whether a given message group is complete. The bean can be an
implementation of the CompletionStrategy interface or a POJO. In the
latter case the completion-strategy-mTethod attribute must be
defined as well. Optional.</para>
</callout>
<callout arearefs="???">
<para>A method defined on the bean referenced by
<code>completion-strategy</code>, <emphasis><emphasis>that
implements the completion decision algorithm.</emphasis> Optional,
with restrictions (see above).</emphasis> Optional.</para>
</callout>
<callout arearefs="???">
<para>The timeout for aggregating messages (counted from the arrival
of the first message). Optional.</para>
</callout>
<callout arearefs="???">
<para>Whether upon the expiration of the timeout, the aggregator
shall try to aggregate the already arrived messages.
<emphasis>Optional (false by default)</emphasis>.</para>
</callout>
<callout arearefs="???">
<para>The interval (in milliseconds) at which a reaper task is
executed, checking if there are any timed out groups.
Optional.</para>
</callout>
<callout arearefs="???">
<para>The capacity of the correlation id tracker. Remembers the
already processed correlation ids, preventing the formation of new
groups for messages that arrive after their group has been already
processed (aggregated or discarded). Optional.</para>
</callout>
<callout arearefs="???">
<para>The timeout for sending out messages. Optional.</para>
</callout>
</calloutlist>
</section>
<section>
<title>Configuring a resequencer by using XML</title>
<para></para>
</section>
</section>
<section>