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Usage clarification of the group-timeout property

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Added some clarification on the usage of  the group-timeout property based on discussion 
https://stackoverflow.com/questions/48230453/issue-with-spring-integration-aggregator-group-timeout-value

* Update aggregator.adoc

Fixed according to one sentence per line rule.
This commit is contained in:
Mike Gorodilin
2019-08-20 14:07:18 +00:00
committed by Artem Bilan
parent 8d1d0eca28
commit f0807fe704
1 changed files with 5 additions and 2 deletions
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7
src/reference/asciidoc/aggregator.adoc
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@@ -470,7 +470,8 @@ By default, an internal `DefaultLockRegistry` is used.
Use of a distributed `LockRegistry`, such as the `ZookeeperLockRegistry`, ensures only one instance of the aggregator can operate on a group concurrently. Use of a distributed `LockRegistry`, such as the `ZookeeperLockRegistry`, ensures only one instance of the aggregator can operate on a group concurrently.
See <<./redis.adoc#redis-lock-registry,Redis Lock Registry>>, <<./gemfire.adoc#gemfire-lock-registry,Gemfire Lock Registry>>, and <<./zookeeper.adoc#zk-lock-registry,Zookeeper Lock Registry>> for more information. See <<./redis.adoc#redis-lock-registry,Redis Lock Registry>>, <<./gemfire.adoc#gemfire-lock-registry,Gemfire Lock Registry>>, and <<./zookeeper.adoc#zk-lock-registry,Zookeeper Lock Registry>> for more information.
<21> A timeout (in milliseconds) to force the `MessageGroup` complete when the `ReleaseStrategy` does not release the group when the current message arrives. <21> A timeout (in milliseconds) to force the `MessageGroup` complete when the `ReleaseStrategy` does not release the group when the current message arrives.
This attribute provides a built-in time-based release strategy for the aggregator when there is a need to emit a partial result (or discard the group) if a new message does not arrive for the `MessageGroup` within the timeout. This attribute provides a built-in time-based release strategy for the aggregator when there is a need to emit a partial result (or discard the group) if a new message does not arrive for the `MessageGroup` within the timeout which counts from the time the last message arrived.
To set up a timeout which counts from the time the `MessageGroup` was created see `group-timeout-expression` information.
When a new message arrives at the aggregator, any existing `ScheduledFuture<?>` for its `MessageGroup` is canceled. When a new message arrives at the aggregator, any existing `ScheduledFuture<?>` for its `MessageGroup` is canceled.
If the `ReleaseStrategy` returns `false` (meaning do not release) and `groupTimeout > 0`, a new task is scheduled to expire the group. If the `ReleaseStrategy` returns `false` (meaning do not release) and `groupTimeout > 0`, a new task is scheduled to expire the group.
We do not advise setting this attribute to zero (or a negative value). We do not advise setting this attribute to zero (or a negative value).
@@ -485,7 +486,9 @@ Used for scheduling the `MessageGroup` to be forced complete.
If the expression evaluates to `null`, the completion is not scheduled. If the expression evaluates to `null`, the completion is not scheduled.
If it evaluates to zero, the group is completed immediately on the current thread. If it evaluates to zero, the group is completed immediately on the current thread.
In effect, this provides a dynamic `group-timeout` property. In effect, this provides a dynamic `group-timeout` property.
See `group-timeout` for more information. As an example, if you wish to forcibly complete a `MessageGroup` after 10 seconds have elapsed since the time the group was created you might consider using the following SpEL expression: `timestamp + 10000 - T(System).currentTimeMillis()` where `timestamp` is provided by `MessageGroup.getTimestamp()` as the `MessageGroup` here is the `#root` evaluation context object.
Bear in mind however that the group creation time might differ from the time of the first arrived message depending on other group expiration properties' configuration.
See `group-timeout` for more information.
Mutually exclusive with 'group-timeout' attribute. Mutually exclusive with 'group-timeout' attribute.
<23> When a group is completed due to a timeout (or by a `MessageGroupStoreReaper`), the group is expired (completely removed) by default. <23> When a group is completed due to a timeout (or by a `MessageGroupStoreReaper`), the group is expired (completely removed) by default.
Late arriving messages start a new group. Late arriving messages start a new group.