Modified: websites/production/camel/content/book-pattern-appendix.html ============================================================================== --- websites/production/camel/content/book-pattern-appendix.html (original) +++ websites/production/camel/content/book-pattern-appendix.html Tue Mar 3 19:21:06 2015 @@ -1714,7 +1714,7 @@ from("direct:line") <p></p><h4 id="BookPatternAppendix-UsingThisPattern.18">Using This Pattern</h4> <p>If you would like to use this EIP Pattern then please read the <a shape="rect" href="getting-started.html">Getting Started</a>, you may also find the <a shape="rect" href="architecture.html">Architecture</a> useful particularly the description of <a shape="rect" href="endpoint.html">Endpoint</a> and <a shape="rect" href="uris.html">URIs</a>. Then you could try out some of the <a shape="rect" href="examples.html">Examples</a> first before trying this pattern out.</p> -<h3 id="BookPatternAppendix-Aggregator">Aggregator</h3><p><strong>This applies for Camel version 2.3 or newer. If you use an older version then use this <a shape="rect" href="aggregator.html">Aggregator</a> link instead.</strong></p><p>The <a shape="rect" class="external-link" href="http://www.enterpriseintegrationpatterns.com/Aggregator.html"; rel="nofollow">Aggregator</a> from the <a shape="rect" href="enterprise-integration-patterns.html">EIP patterns</a> allows you to combine a number of messages together into a single message.</p><p><img class="confluence-embedded-image confluence-external-resource" src="http://www.enterpriseintegrationpatterns.com/img/Aggregator.gif"; data-image-src="http://www.enterpriseintegrationpatterns.com/img/Aggregator.gif";></p><p>A correlation <a shape="rect" href="expression.html">Expression</a> is used to determine the messages which should be aggregated together. If you want to aggregate all messages into a single message, just use a constant expressi on. An AggregationStrategy is used to combine all the message exchanges for a single correlation key into a single message exchange.</p><h3 id="BookPatternAppendix-Aggregatoroptions">Aggregator options</h3><p>The aggregator supports the following options:</p><div class="confluenceTableSmall"><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>Option</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Default</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Description</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>correlationExpression</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Mandatory <a shape="rect" href="expression.html">Expression</a> which evaluates the correlation key to use for aggregation. The <a shape="rect" href="exchange.html">Exchange</a> which has the same correlation key is aggre gated together. If the correlation key could not be evaluated an Exception is thrown. You can disable this by using the <code>ignoreBadCorrelationKeys</code> option.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>aggregationStrategy</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Mandatory <code>AggregationStrategy</code> which is used to <em>merge</em> the incoming <a shape="rect" href="exchange.html">Exchange</a> with the existing already merged exchanges. At first call the <code>oldExchange</code> parameter is <code>null</code>. On subsequent invocations the <code>oldExchange</code> contains the merged exchanges and <code>newExchange</code> is of course the new incoming Exchange. From <strong>Camel 2.9.2</strong> onwards the strategy can also be a <code>TimeoutAwareAggregationStrategy</code> implementation, supporting the timeout callback, see further below for more details.</p></ td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>strategyRef</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>A reference to lookup the <code>AggregationStrategy</code> in the <a shape="rect" href="registry.html">Registry</a>. From <strong>Camel 2.12</strong> onwards you can also use a POJO as the <code>AggregationStrategy</code>, see further below for details.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>strategyMethodName</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> This option can be used to explicit declare the method name to use, when using POJOs as the <code>AggregationStrategy</code>. See further below for more details.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>strategyMethodAllowNull</p></td><td colspan="1" rowspan="1" class ="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> If this option is <code>false</code> then the aggregate method is not used for the very first aggregation. If this option is <code>true</code> then <code>null</code> values is used as the <code>oldExchange</code> (at the very first aggregation), when using POJOs as the <code>AggregationStrategy</code>. See further below for more details.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>completionSize</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Number of messages aggregated before the aggregation is complete. This option can be set as either a fixed value or using an <a shape="rect" href="expression.html">Expression</a> which allows you to evaluate a size dynamically - will use <code>Integer</code> as result. If both are set Camel will fallback to use the fi xed value if the <a shape="rect" href="expression.html">Expression</a> result was <code>null</code> or <code>0</code>.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>completionTimeout</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Time in millis that an aggregated exchange should be inactive before its complete. This option can be set as either a fixed value or using an <a shape="rect" href="expression.html">Expression</a> which allows you to evaluate a timeout dynamically - will use <code>Long</code> as result. If both are set Camel will fallback to use the fixed value if the <a shape="rect" href="expression.html">Expression</a> result was <code>null</code> or <code>0</code>. You cannot use this option together with completionInterval, only one of the two can be used.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>completionInterval</p></td><td colspan="1" row span="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>A repeating period in millis by which the aggregator will complete all current aggregated exchanges. Camel has a background task which is triggered every period. You cannot use this option together with completionTimeout, only one of them can be used.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>completionPredicate</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>A <a shape="rect" href="predicate.html">Predicate</a> to indicate when an aggregated exchange is complete.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>completionFromBatchConsumer</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>This option is if the exchanges are coming from a <a shape="rect" href="batch-consumer .html">Batch Consumer</a>. Then when enabled the <a shape="rect" href="aggregator2.html">Aggregator2</a> will use the batch size determined by the <a shape="rect" href="batch-consumer.html">Batch Consumer</a> in the message header <code>CamelBatchSize</code>. See more details at <a shape="rect" href="batch-consumer.html">Batch Consumer</a>. This can be used to aggregate all files consumed from a <a shape="rect" href="file2.html">File</a> endpoint in that given poll.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>forceCompletionOnStop</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.9</strong> Indicates to complete all current aggregated exchanges when the context is stopped</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>eagerCheckCompletion</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colsp an="1" rowspan="1" class="confluenceTd"><p>Whether or not to eager check for completion when a new incoming <a shape="rect" href="exchange.html">Exchange</a> has been received. This option influences the behavior of the <code>completionPredicate</code> option as the <a shape="rect" href="exchange.html">Exchange</a> being passed in changes accordingly. When <code>false</code> the <a shape="rect" href="exchange.html">Exchange</a> passed in the <a shape="rect" href="predicate.html">Predicate</a> is the <em>aggregated</em> Exchange which means any information you may store on the aggregated Exchange from the <code>AggregationStrategy</code> is available for the <a shape="rect" href="predicate.html">Predicate</a>. When <code>true</code> the <a shape="rect" href="exchange.html">Exchange</a> passed in the <a shape="rect" href="predicate.html">Predicate</a> is the <em>incoming</em> <a shape="rect" href="exchange.html">Exchange</a>, which means you can access data from the incoming Exchange. </p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>groupExchanges</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If enabled then Camel will group all aggregated Exchanges into a single combined <code>org.apache.camel.impl.GroupedExchange</code> holder class that holds all the aggregated Exchanges. And as a result only one Exchange is being sent out from the aggregator. Can be used to combine many incoming Exchanges into a single output Exchange without coding a custom <code>AggregationStrategy</code> yourself. <strong>Important:</strong> This option does <strong>not</strong> support persistent repository with the aggregator. See further below for an example and more details.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>ignoreInvalidCorrelationKeys</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" r owspan="1" class="confluenceTd"><p>Whether or not to ignore correlation keys which could not be evaluated to a value. By default Camel will throw an Exception, but you can enable this option and ignore the situation instead.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>closeCorrelationKeyOnCompletion</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Whether or not too <em>late</em> Exchanges should be accepted or not. You can enable this to indicate that if a correlation key has already been completed, then any new exchanges with the same correlation key be denied. Camel will then throw a <code>closedCorrelationKeyException</code> exception. When using this option you pass in a <code>integer</code> which is a number for a LRUCache which keeps that last X number of closed correlation keys. You can pass in 0 or a negative value to indicate a unbounded cache. By passing in a number you are ensured that cache won't grow too big if you use a log of different correlation keys.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>discardOnCompletionTimeout</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.5:</strong> Whether or not exchanges which complete due to a timeout should be discarded. If enabled then when a timeout occurs the aggregated message will <strong>not</strong> be sent out but dropped (discarded).</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>aggregationRepository</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Allows you to plugin you own implementation of <code>org.apache.camel.spi.AggregationRepository</code> which keeps track of the current inflight aggregated exchanges. Camel uses by default a memory based implementation.</p>< /td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>aggregationRepositoryRef</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Reference to lookup a <code>aggregationRepository</code> in the <a shape="rect" href="registry.html">Registry</a>.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>parallelProcessing</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>When aggregated are completed they are being send out of the aggregator. This option indicates whether or not Camel should use a thread pool with multiple threads for concurrency. If no custom thread pool has been specified then Camel creates a default pool with 10 concurrent threads.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>executorService</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> < /p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If using <code>parallelProcessing</code> you can specify a custom thread pool to be used. In fact also if you are not using <code>parallelProcessing</code> this custom thread pool is used to send out aggregated exchanges as well.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>executorServiceRef</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Reference to lookup a <code>executorService</code> in the <a shape="rect" href="registry.html">Registry</a></p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>timeoutCheckerExecutorService</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.9:</strong> If using either of the <code>completionTimeout</code>, <code>completionTimeoutExpression</code>, or <code>completionInterval</code > options a background thread is created to check for the completion for every > aggregator. Set this option to provide a custom thread pool to be used > rather than creating a new thread for every aggregator.</p></td></tr><tr><td > colspan="1" rowspan="1" > class="confluenceTd"><p>timeoutCheckerExecutorServiceRef</p></td><td > colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td > colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.9:</strong> > Reference to lookup a <code>timeoutCheckerExecutorService</code> in the <a > shape="rect" href="registry.html">Registry</a></p></td></tr><tr><td > colspan="1" rowspan="1" > class="confluenceTd"><p>optimisticLocking</p></td><td colspan="1" > rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td > colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.11:</strong> > Turns on using optimistic locking, which requires the > <code>aggregationRepository</code> being used, is supporting this by > implementing the <code>org.apache. camel.spi.OptimisticLockingAggregationRepository</code> interface.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>optimisticLockRetryPolicy</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.11.1:</strong> Allows to configure retry settings when using optimistic locking.</p></td></tr></tbody></table></div></div><h3 id="BookPatternAppendix-ExchangeProperties">Exchange Properties</h3><p>The following properties are set on each aggregated Exchange:</p><div class="confluenceTableSmall"><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>header</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>type</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>description</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>CamelAggregatedSize</code></p></td><td colspan="1" rowspan= "1" class="confluenceTd"><p>int</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>The total number of Exchanges aggregated into this combined Exchange.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>CamelAggregatedCompletedBy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>String</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Indicator how the aggregation was completed as a value of either: <code>predicate</code>, <code>size</code>, <code>consumer</code>, <code>timeout</code>, <code>forceCompletion</code> or <code>interval</code>.</p></td></tr></tbody></table></div></div><h3 id="BookPatternAppendix-AboutAggregationStrategy">About AggregationStrategy</h3><p>The <code>AggregationStrategy</code> is used for aggregating the old (lookup by its correlation id) and the new exchanges together into a single exchange. Possible implementations include performing some kind of combining or delta processing, such as adding line items together into an invoice or just using the newest exchange and removing old exchanges such as for state tracking or market data prices; where old values are of little use.</p><p>Notice the aggregation strategy is a mandatory option and must be provided to the aggregator.</p><p>Here are a few example AggregationStrategy implementations that should help you create your own custom strategy.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl"> +<h3 id="BookPatternAppendix-Aggregator">Aggregator</h3><p><strong>This applies for Camel version 2.3 or newer. If you use an older version then use this <a shape="rect" href="aggregator.html">Aggregator</a> link instead.</strong></p><p>The <a shape="rect" class="external-link" href="http://www.enterpriseintegrationpatterns.com/Aggregator.html"; rel="nofollow">Aggregator</a> from the <a shape="rect" href="enterprise-integration-patterns.html">EIP patterns</a> allows you to combine a number of messages together into a single message.</p><p><img class="confluence-embedded-image confluence-external-resource" src="http://www.enterpriseintegrationpatterns.com/img/Aggregator.gif"; data-image-src="http://www.enterpriseintegrationpatterns.com/img/Aggregator.gif";></p><p>A correlation <a shape="rect" href="expression.html">Expression</a> is used to determine the messages which should be aggregated together. If you want to aggregate all messages into a single message, just use a constant expressi on. An AggregationStrategy is used to combine all the message exchanges for a single correlation key into a single message exchange.</p><h3 id="BookPatternAppendix-Aggregatoroptions">Aggregator options</h3><p>The aggregator supports the following options:</p><div class="confluenceTableSmall"><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>Option</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Default</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Description</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>correlationExpression</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Mandatory <a shape="rect" href="expression.html">Expression</a> which evaluates the correlation key to use for aggregation. The <a shape="rect" href="exchange.html">Exchange</a> which has the same correlation key is aggre gated together. If the correlation key could not be evaluated an Exception is thrown. You can disable this by using the <code>ignoreBadCorrelationKeys</code> option.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>aggregationStrategy</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Mandatory <code>AggregationStrategy</code> which is used to <em>merge</em> the incoming <a shape="rect" href="exchange.html">Exchange</a> with the existing already merged exchanges. At first call the <code>oldExchange</code> parameter is <code>null</code>. On subsequent invocations the <code>oldExchange</code> contains the merged exchanges and <code>newExchange</code> is of course the new incoming Exchange. From <strong>Camel 2.9.2</strong> onwards the strategy can also be a <code>TimeoutAwareAggregationStrategy</code> implementation, supporting the timeout callback, see further below for more details.</p></ td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>strategyRef</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>A reference to lookup the <code>AggregationStrategy</code> in the <a shape="rect" href="registry.html">Registry</a>. From <strong>Camel 2.12</strong> onwards you can also use a POJO as the <code>AggregationStrategy</code>, see further below for details.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>strategyMethodName</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> This option can be used to explicit declare the method name to use, when using POJOs as the <code>AggregationStrategy</code>. See further below for more details.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>strategyMethodAllowNull</p></td><td colspan="1" rowspan="1" class ="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.12:</strong> If this option is <code>false</code> then the aggregate method is not used for the very first aggregation. If this option is <code>true</code> then <code>null</code> values is used as the <code>oldExchange</code> (at the very first aggregation), when using POJOs as the <code>AggregationStrategy</code>. See further below for more details.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>completionSize</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Number of messages aggregated before the aggregation is complete. This option can be set as either a fixed value or using an <a shape="rect" href="expression.html">Expression</a> which allows you to evaluate a size dynamically - will use <code>Integer</code> as result. If both are set Camel will fallback to use the fi xed value if the <a shape="rect" href="expression.html">Expression</a> result was <code>null</code> or <code>0</code>.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>completionTimeout</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Time in millis that an aggregated exchange should be inactive before its complete. This option can be set as either a fixed value or using an <a shape="rect" href="expression.html">Expression</a> which allows you to evaluate a timeout dynamically - will use <code>Long</code> as result. If both are set Camel will fallback to use the fixed value if the <a shape="rect" href="expression.html">Expression</a> result was <code>null</code> or <code>0</code>. You cannot use this option together with completionInterval, only one of the two can be used.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>completionInterval</p></td><td colspan="1" row span="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>A repeating period in millis by which the aggregator will complete all current aggregated exchanges. Camel has a background task which is triggered every period. You cannot use this option together with completionTimeout, only one of them can be used.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>completionPredicate</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>A <a shape="rect" href="predicate.html">Predicate</a> to indicate when an aggregated exchange is complete. Starting in <strong>Camel 2.15</strong>, if this is not specified and the AggregationStrategy object implements Predicate, the aggregationStrategy object will be used as the completionPredicate.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>completionFromBatchConsumer</p></td><td colspan="1" rowspa n="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>This option is if the exchanges are coming from a <a shape="rect" href="batch-consumer.html">Batch Consumer</a>. Then when enabled the <a shape="rect" href="aggregator2.html">Aggregator2</a> will use the batch size determined by the <a shape="rect" href="batch-consumer.html">Batch Consumer</a> in the message header <code>CamelBatchSize</code>. See more details at <a shape="rect" href="batch-consumer.html">Batch Consumer</a>. This can be used to aggregate all files consumed from a <a shape="rect" href="file2.html">File</a> endpoint in that given poll.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>forceCompletionOnStop</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.9</strong> Indicates to complete all current aggregated exchanges when the context is stopped</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>eagerCheckCompletion</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Whether or not to eager check for completion when a new incoming <a shape="rect" href="exchange.html">Exchange</a> has been received. This option influences the behavior of the <code>completionPredicate</code> option as the <a shape="rect" href="exchange.html">Exchange</a> being passed in changes accordingly. When <code>false</code> the <a shape="rect" href="exchange.html">Exchange</a> passed in the <a shape="rect" href="predicate.html">Predicate</a> is the <em>aggregated</em> Exchange which means any information you may store on the aggregated Exchange from the <code>AggregationStrategy</code> is available for the <a shape="rect" href="predicate.html">Predicate</a>. When <code>true</code> the <a shape="rect" href="exchange.html">Exchange</a> passed in the <a shape="rect" href="predicate.html">Predicate</a> is the <em>incoming</em> <a shape="rect" href="exchange.html">Exchange</a>, which means you can access data from the incoming Exchange.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>groupExchanges</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If enabled then Camel will group all aggregated Exchanges into a single combined <code>org.apache.camel.impl.GroupedExchange</code> holder class that holds all the aggregated Exchanges. And as a result only one Exchange is being sent out from the aggregator. Can be used to combine many incoming Exchanges into a single output Exchange without coding a custom <code>AggregationStrategy</code> yourself. <strong>Important:</strong> This option does <strong>not</strong> support persistent repository with the aggregator. See further below for an example and more details.</p></td ></tr><tr><td colspan="1" rowspan="1" >class="confluenceTd"><p>ignoreInvalidCorrelationKeys</p></td><td colspan="1" >rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td >colspan="1" rowspan="1" class="confluenceTd"><p>Whether or not to ignore >correlation keys which could not be evaluated to a value. By default Camel >will throw an Exception, but you can enable this option and ignore the >situation instead.</p></td></tr><tr><td colspan="1" rowspan="1" >class="confluenceTd"><p>closeCorrelationKeyOnCompletion</p></td><td >colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td >colspan="1" rowspan="1" class="confluenceTd"><p>Whether or not too ><em>late</em> Exchanges should be accepted or not. You can enable this to >indicate that if a correlation key has already been completed, then any new >exchanges with the same correlation key be denied. Camel will then throw a ><code>closedCorrelationKeyException</code> exception. When using this option >you pass in a <code>integer< /code> which is a number for a LRUCache which keeps that last X number of closed correlation keys. You can pass in 0 or a negative value to indicate a unbounded cache. By passing in a number you are ensured that cache won't grow too big if you use a log of different correlation keys.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>discardOnCompletionTimeout</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.5:</strong> Whether or not exchanges which complete due to a timeout should be discarded. If enabled then when a timeout occurs the aggregated message will <strong>not</strong> be sent out but dropped (discarded).</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>aggregationRepository</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Allows you to plugin you own implementation of <code>org.apache.camel.spi.AggregationRepository</code> which keeps track of the current inflight aggregated exchanges. Camel uses by default a memory based implementation.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>aggregationRepositoryRef</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Reference to lookup a <code>aggregationRepository</code> in the <a shape="rect" href="registry.html">Registry</a>.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>parallelProcessing</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>When aggregated are completed they are being send out of the aggregator. This option indicates whether or not Camel should use a thread pool with multiple threads for concurrency. If no custom thread pool has been specified then Camel creates a default pool with 10 concurrent threads.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>executorService</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If using <code>parallelProcessing</code> you can specify a custom thread pool to be used. In fact also if you are not using <code>parallelProcessing</code> this custom thread pool is used to send out aggregated exchanges as well.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>executorServiceRef</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Reference to lookup a <code>executorService</code> in the <a shape="rect" href="registry.html">Registry</a></p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>timeoutCheckerExecutorService</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.9:</strong> If using either of the <code>completionTimeout</code>, <code>completionTimeoutExpression</code>, or <code>completionInterval</code> options a background thread is created to check for the completion for every aggregator. Set this option to provide a custom thread pool to be used rather than creating a new thread for every aggregator.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>timeoutCheckerExecutorServiceRef</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.9:</strong> Reference to lookup a <code>timeoutCheckerExecutorService</code> in the <a shape="rect" href="registry.html">Registry</a></p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>optimisticLocking</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluen ceTd"><p><strong>Camel 2.11:</strong> Turns on using optimistic locking, which requires the <code>aggregationRepository</code> being used, is supporting this by implementing the <code>org.apache.camel.spi.OptimisticLockingAggregationRepository</code> interface.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>optimisticLockRetryPolicy</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.11.1:</strong> Allows to configure retry settings when using optimistic locking.</p></td></tr></tbody></table></div></div><h3 id="BookPatternAppendix-ExchangeProperties">Exchange Properties</h3><p>The following properties are set on each aggregated Exchange:</p><div class="confluenceTableSmall"><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>header</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>type</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>description</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>CamelAggregatedSize</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>int</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>The total number of Exchanges aggregated into this combined Exchange.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>CamelAggregatedCompletedBy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>String</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Indicator how the aggregation was completed as a value of either: <code>predicate</code>, <code>size</code>, <code>consumer</code>, <code>timeout</code>, <code>forceCompletion</code> or <code>interval</code>.</p></td></tr></tbody></table></div></div><h3 id="BookPatternAppendix-AboutAggregationStrategy">About AggregationStrategy</h3><p>The <code>AggregationStrategy</code> is used for aggregating the ol d (lookup by its correlation id) and the new exchanges together into a single exchange. Possible implementations include performing some kind of combining or delta processing, such as adding line items together into an invoice or just using the newest exchange and removing old exchanges such as for state tracking or market data prices; where old values are of little use.</p><p>Notice the aggregation strategy is a mandatory option and must be provided to the aggregator.</p><p>Here are a few example AggregationStrategy implementations that should help you create your own custom strategy.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl"> <script class="theme: Default; brush: java; gutter: false" type="syntaxhighlighter"><![CDATA[//simply combines Exchange String body values using '+' as a delimiter class StringAggregationStrategy implements AggregationStrategy { @@ -1749,7 +1749,7 @@ class ArrayListAggregationStrategy imple } } ]]></script> -</div></div><h3 id="BookPatternAppendix-Aboutcompletion">About completion</h3><p>When aggregation <a shape="rect" href="exchange.html">Exchange</a>s at some point you need to indicate that the aggregated exchanges is complete, so they can be send out of the aggregator. Camel allows you to indicate completion in various ways as follows:</p><ul class="alternate"><li>completionTimeout - Is an inactivity timeout in which is triggered if no new exchanges have been aggregated for that particular correlation key within the period.</li><li>completionInterval - Once every X period all the current aggregated exchanges are completed.</li><li>completionSize - Is a number indicating that after X aggregated exchanges it's complete.</li><li>completionPredicate - Runs a <a shape="rect" href="predicate.html">Predicate</a> when a new exchange is aggregated to determine if we are complete or not</li><li>completionFromBatchConsumer - Special option for <a shape="rect" href="batch-consumer.html">Batch C onsumer</a> which allows you to complete when all the messages from the batch has been aggregated.</li><li>forceCompletionOnStop - <strong>Camel 2.9</strong> Indicates to complete all current aggregated exchanges when the context is stopped</li></ul><p>Notice that all the completion ways are per correlation key. And you can combine them in any way you like. It's basically the first which triggers that wins. So you can use a completion size together with a completion timeout. Only completionTimeout and completionInterval cannot be used at the same time.</p><p>Notice the completion is a mandatory option and must be provided to the aggregator. If not provided Camel will thrown an Exception on startup.</p> <div class="aui-message success shadowed information-macro"> +</div></div><h3 id="BookPatternAppendix-Aboutcompletion">About completion</h3><p>When aggregation <a shape="rect" href="exchange.html">Exchange</a>s at some point you need to indicate that the aggregated exchanges is complete, so they can be send out of the aggregator. Camel allows you to indicate completion in various ways as follows:</p><ul class="alternate"><li>completionTimeout - Is an inactivity timeout in which is triggered if no new exchanges have been aggregated for that particular correlation key within the period.</li><li>completionInterval - Once every X period all the current aggregated exchanges are completed.</li><li>completionSize - Is a number indicating that after X aggregated exchanges it's complete.</li><li>completionPredicate - Runs a <a shape="rect" href="predicate.html">Predicate</a> when a new exchange is aggregated to determine if we are complete or not. Staring in <strong>Camel 2.15</strong>, the configured aggregationStrategy can implement the Predicat e interface and will be used as the completionPredicate if no completionPredicate is configured.</li><li>completionFromBatchConsumer - Special option for <a shape="rect" href="batch-consumer.html">Batch Consumer</a> which allows you to complete when all the messages from the batch has been aggregated.</li><li>forceCompletionOnStop - <strong>Camel 2.9</strong> Indicates to complete all current aggregated exchanges when the context is stopped</li></ul><p>Notice that all the completion ways are per correlation key. And you can combine them in any way you like. It's basically the first which triggers that wins. So you can use a completion size together with a completion timeout. Only completionTimeout and completionInterval cannot be used at the same time.</p><p>Notice the completion is a mandatory option and must be provided to the aggregator. If not provided Camel will thrown an Exception on startup.</p> <div class="aui-message success shadowed information-macro"> <p class="title">Callbacks</p> <span class="aui-icon icon-success">Icon</span> <div class="message-content">
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