diff --git a/docs/src/reference/docbook/aggregator.xml b/docs/src/reference/docbook/aggregator.xml
index 585d3f30d8..b37f0b0e1d 100644
--- a/docs/src/reference/docbook/aggregator.xml
+++ b/docs/src/reference/docbook/aggregator.xml
@@ -323,7 +323,8 @@
id="aggxmlCorrelationStrategyMethod" />
+ send-timeout="86420000" ]]>
@@ -420,6 +421,10 @@
The timeout for sending the aggregated messages to the output or
reply channel. Optional.
+
+
+ SpEL expression to handle release strategy Optional.
+
Using a "ref" attribute is generally recommended if a custom
@@ -492,6 +497,38 @@
strategy method and the aggregator method can be combined in a single
bean (all of them or any two).
+
+
+ Aggregators and Spring Expression Language (SpEL)
+
+
+
+ Since Spring Integration 2.0, the release strategy may be handled with SpEL (http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/expressions.html)
+ which would be recommend if the logic behind such release strategy is relatively simple.
+ Let's say you have a legacy component which was designed to receive an array of objects. We know that default release
+ strategy will assemble all aggregated messages in the List. So now we have two problems. First we need to extract individual
+ messages form such list, extract payload of each message and assemble them into the array of objects (see code below)
+
+ > mesages){
+ List strList = new ArrayList();
+ for (Message message : mesages) {
+ strList.add(message.getPayload());
+ }
+ return strList.toArray(new String[]{});
+}]]>
+
+ However, with SpEL such requirement could actually be handled relatively easy with a simple
+ one-line expression, thus sparing you from writing a custom class and configuring it as a bean.
+
+ ]]>
+
+ In the above configuration we are using Collection Projection expression
+ (http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/expressions.html#d0e12113) to
+ assemble a new collection from the payloads of all messages in the list and then transforming it to an Array, thus
+ achieving the same result as the java code above.
+