# cAggregate Combines a number of messages together into a single message. For more information, see the Apache camel documentation https://camel.apache.org/components/latest/. ## cAggregate Standard properties These properties are used to configure cAggregate running in the Standard Job framework. The Standard cAggregate component belongs to the Routing family. ## Basic settings | Properties | Description | | --- | --- | | Language | Select the language of the expression you want to use to filter your
messages, from None, Bean, CONSTANT, ESBCorrelationID, EL,
GROOVY, HEADER, JoSQL,
JSonPath, JXPATH, MVEL,
OGNL, PHP, PROPERTY,
PYTHON, RUBY, SIMPLE,
SpEL, SQL, XPATH, and
XQUERY.

Select CorrelationID to use the
existing correlation ID of the message as the correlation key if the
correlation ID is available in the closest cSOAP connected to this component. For more information
about the cSOAP component, see [cSOAP](https://help.qlik.com/talend/en-US/components/8.0/mediation-apache-cxf/csoap). | | Correlation expression/Expression | Type in the expression that evaluates the correlation key to be
used for the aggregation.

This field disappears when CorrelationID is selected in the Language list. In this case, the existing correlation
ID from the closest cSOAP connected
to this component will be used. For more information about the
cSOAP component, see [cSOAP](https://help.qlik.com/talend/en-US/components/8.0/mediation-apache-cxf/csoap). | | Correlation expression/Add Namespaces | This option appears when XPath is
selected in the Language list.

Select this check box to add namespaces for the Xpath expression.
Click [+] to add as many namespaces
as required to the table and define the prefix and URI in the
corresponding columns. | | Strategy | Specify a Java bean to use as the aggregation strategy or select a
predefined aggregation strategy.



Information noteNote: The predefined aggregation strategies are available only if you have
installed the R2024-10 Talend Studio Monthly update or a later one delivered by Talend. For more information, check with your administrator. | | Completion conditions/Number of messages | Select this check box to specify the number of messages to
aggregate per batch before the aggregation is complete.

Information noteNote:

By default, this check box is selected and the number of
messages is set to *3*. If you
clear this check box, and at least one of the other four
completion conditions is met, all the messages retrieved will be
aggregated in one batch. | | Completion conditions/Inactivity timeout (in milliseconds) | Select this check box to specify the time (in milliseconds) that
an aggregated exchange should be inactive before it is complete.
This option can be set as either a fixed value or using an
Expression which allows you to evaluate a timeout dynamically.

Information noteNote:

You can not use this option together with Scheduled interval. Only one of them
can be used at a time. | | Completion conditions/Scheduled interval (in milliseconds) | Select this check box to specify a repeating period (in
milliseconds) by which the aggregator will complete all current
aggregated exchanges.

Information noteNote:

You cannot use this option together with Inactivity timeout. Only one of them can be used
at a time. | | Completion conditions/Predicate matched | Select this check box to specify a predicate to indicate
when an aggregated exchange is complete. | | Completion conditions/Batch consumer | Select this check box to aggregate all files consumed
from a file endpoint in a given poll. | ## Advanced settings | Properties | Description | | --- | --- | | Check completion before aggregating | Select this check box to check for completion when a new
incoming exchange has been received. This option influences the behavior
of the Predicate matched option as the
exchange being passed in changes accordingly. When this option is
disabled, the exchange passed in the predicate is the *aggregated* exchange which means any
information you may store on the aggregated exchange from the
aggregation strategy is available for the predicate. When this option is
enabled, the exchange passed in the predicate is the *incoming* exchange, which means you can
access data from the incoming exchange. | | Close correlation group | Select this check box to indicate that if a correlation
key has already been completed, then any new exchanges with the same
correlation key will be denied. When using this option, enter a number
in the Maximum bound field to keep that
last number of closed correlation keys. | | Ignore invalid correlation key | Select this check box to ignore the invalid correlation
key which could not be evaluated to a value. By default Camel will throw
an Exception on encountering an invalid correlation key. | | Group arriving exchange | Select this check box to group all aggregated exchanges
into a single combined holder class that holds all the aggregated
exchanges. As a result only one exchange is being sent out from the
aggregator. This option can be used to combine many incoming exchanges
into a single output exchange. | | Use persistence | Select this check box to plug in your own implementation
of the repository which keeps track of the current in-flight aggregated
exchanges. By default, Camel uses a memory based implementation. | | Repository | This field appears when the Use persistence
check box is selected. The repository is AggregationRepository or RecoverableAggregationRepository.


AggregationRepository:
The default repository used by Camel which is a memory based
implementation. Enter the name of the repository in the field.


RecoverableAggregationRepository:
RecoverableAggregationRepository is a JDBC based
AggregationRepository which persists the aggregated messages on the
fly. This ensures that you will not loose messages. Enter the name
of the repository in the field.

With this repository selected, the following options
appear:


Recovery/Use recovery: Select
this check box to recover failed aggregated exchanges and have them
resubmitted automatically. In the Recovery
interval field, enter the interval (in milliseconds)
to scan for failed exchanges to recover and resubmit. By default
this interval is 5000 milliseconds. In the Dead letter channel field, enter an endpoint URI for
a Dead Letter Channel where exhausted recovered exchanges will be
moved. In the Maximum redeliveries
field, enter the maximum number of redelivery attempts for a given
recovered exchange. | ## Usage | Usage guidance | Description | | --- | --- | | **Usage rule** | cAggregate is used as a middle or
end component in a Route. | | Connections | Aggregate: select this link to route
messages to the next endpoint according to the selected aggregation
strategy.


Route: select this link to route all the messages from the
sender to the next endpoint. | **Related concepts** * [Aggregating three messages into one](https://help.qlik.com/talend/en-US/mediation-components/8.0/mediation-aggregate/caggregate-cprocessor-cfile-cfile-aggregating-three-messages-into-one)