Sample 362: Perform Database Lookups and Updates in the Same Mediation Sequence
<definitions xmlns="http://ws.apache.org/ns/synapse">
<sequence name="main">
<in>
<send>
<endpoint>
<address uri="http://localhost:9000/services/SimpleStockQuoteService"/>
</endpoint>
</send>
</in>
<out>
<log level="custom">
<property name="text" value="** Reporting to the Database **"/>
</log>
<dbreport>
<connection>
<pool>
<driver>org.apache.derby.jdbc.ClientDriver</driver>
<url>jdbc:derby://localhost:1527/synapsedb;create=false</url>
<user>synapse</user>
<password>synapse</password>
</pool>
</connection>
<statement>
<sql>update company set price=? where name =?</sql>
<parameter xmlns:m0="http://services.samples"
expression="//m0:return/m0:last/child::text()" type="DOUBLE"/>
<parameter xmlns:m0="http://services.samples"
expression="//m0:return/m0:symbol/child::text()" type="VARCHAR"/>
</statement>
</dbreport>
<log level="custom">
<property name="text" value="** Looking up from the Database **"/>
</log>
<dblookup>
<connection>
<pool>
<driver>org.apache.derby.jdbc.ClientDriver</driver>
<url>jdbc:derby://localhost:1527/synapsedb;create=false</url>
<user>synapse</user>
<password>synapse</password>
</pool>
</connection>
<statement>
<sql>select * from company where name =?</sql>
<parameter xmlns:m0="http://services.samples"
expression="//m0:return/m0:symbol/child::text()" type="VARCHAR"/>
<result name="stock_price" column="price"/>
</statement>
</dblookup>
<log level="custom">
<property name="text"
expression="fn:concat('Stock price - ',get-property('stock_price'))"/>
</log>
<send/>
</out>
</sequence>
</definitions>
Objective
Sample 360 and sample 361
shows how to use the dblookup mediator and dbreport mediator separately. This sample
combines them in a single mediation sequence to perform both database lookup and
update operations.
Executing the Client
In this sample, the dbreport mediator works the same way as in
sample 361. It updates the price for the given company
using the response messages content. Then the dblookup mediator reads the last
updated value from the company database and logs it to the console.
Run the sample client as follows.
ant stockquote -Daddurl=http://localhost:9000/services/SimpleStockQuoteService -Dtrpurl=http://localhost:8280/ -Dsymbol=IBM
Synapse will update the database using the stock quote value available in the
response sent by Axis2. Then the same value will be retrieved from the database
and logged as follows.
INFO LogMediator text = ** Reporting to the Database **
...
INFO LogMediator text = ** Looking up from the Database **
...
INFO LogMediator text = Stock price - 153.47886496064808
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