Sequence Mediator

The Sequence mediator is used to invoke an already configured named sequence of mediators. This is useful when you need to reuse a particular set of mediators in a given order.

Syntax

<sequence key="name"/>

Configuration

The parameters available to configure the Sequence mediator are as follows.

Parameter Name	Description
Referring sequence	This is the reference key of the already configured sequence. Possible values are as follows. the name of the referring sequence as the key. if the sequence is configured in the registry, give the registry path as the key. a dynamic value by entering an expression as the key.

Examples

In this example, the following sequence named StoreSend includes a store mediator to store the request in a message store named JMSMS and a call mediator to send it to an endpoint afterwards.

SequenceEndpoint

<sequence name="StoreSend" trace="disable" xmlns="http://ws.apache.org/ns/synapse">
    <store messageStore="JMSMS"/>
    <call>
        <endpoint key="simplestockep"/>
    </call>
</sequence>

<?xml version="1.0" encoding="UTF-8"?>
<endpoint name="simplestockep" xmlns="http://ws.apache.org/ns/synapse">
    <address uri="http://localhost:9000/services/SimpleStockQuoteService">
        <suspendOnFailure>
            <initialDuration>-1</initialDuration>
            <progressionFactor>1</progressionFactor>
        </suspendOnFailure>
        <markForSuspension>
            <retriesBeforeSuspension>0</retriesBeforeSuspension>
        </markForSuspension>
    </address>
</endpoint>

The Sequence mediator configuration can be as follows to invoke the StoreSend sequence after using a payloadFactory mediator to transform the contents of the request.

Example 1: If the StoreSend sequence configured in registry

<inSequence>
    <payloadFactory media-type="xml" template-type="default">
        <format>
            <m:checkpriceresponse xmlns:m="http://services.samples/xsd">
                <m:code>$1</m:code>
                <m:price>$2</m:price>
            </m:checkpriceresponse>
        </format>
        <args>
            <arg expression="//m0:symbol" evaluator="xml" xmlns:m0="http://services.samples/xsd"/>
            <arg expression="//m0:last" evaluator="xml" xmlns:m0="http://services.samples/xsd"/>
        </args>
    </payloadFactory>
    <sequence key="conf:StoreSend.xml"/>
</inSequence>

Example 2: If the StoreSend sequence configured as a named sequence

<inSequence>
    <payloadFactory media-type="xml" template-type="default">
        <format>
            <m:checkpriceresponse xmlns:m="http://services.samples/xsd">
                <m:code>$1</m:code>
                <m:price>$2</m:price>
            </m:checkpriceresponse>
        </format>
        <args>
            <arg expression="//m0:symbol" evaluator="xml" xmlns:m0="http://services.samples/xsd"/>
            <arg expression="//m0:last" evaluator="xml" xmlns:m0="http://services.samples/xsd"/>
        </args>
    </payloadFactory>
    <sequence key="StoreSend"/>
</inSequence>

Example 3: If the StoreSend sequence can be derived dynamically

<inSequence>
    <payloadFactory media-type="xml" template-type="default">
        <format>
            <m:checkpriceresponse xmlns:m="http://services.samples/xsd">
                <m:code>$1</m:code>
                <m:price>$2</m:price>
            </m:checkpriceresponse>
        </format>
        <args>
            <arg expression="//m0:symbol" evaluator="xml" xmlns:m0="http://services.samples/xsd"/>
            <arg expression="//m0:last" evaluator="xml" xmlns:m0="http://services.samples/xsd"/>
        </args>
    </payloadFactory>
    <property name="seqName" value="StoreSend"/>
    <sequence key="{$ctx:seqName}"/>
</inSequence>