Help about SpEL expression

[nuvola]

Hi all,

in my scenario the header could contain a 'customer attribute' MessageId:

[Headers={timestamp=1339161965407, id=..., JMSXDeliveryCount=1, jms_type=bp_list, jms_timestamp=1339161963190, jms_redelivered=false, MessageId=..., jms_messageId=...}]

That 'customer attribute' is not mandatory so in some cases is not present.
I would like to use it around my spring context file when I want to trace the incoming request:

...
    <!--  Dispatch message -->
    <file:outbound-gateway directory="file:${unmatchedMessageType.directory}"
        request-channel="unmatchedMessageTypeChannel" reply-channel="generatedFileChannel"
        filename-generator-expression="'${queue.jndi.name}' + '_' + headers.MessageId + '.xml'"/>
...

When MessageId is not present I would like to use instead headers.jms_messageId.
So the logic should be: if headers contains MessageId use it else use jms_messageId.

I was not able to code that logic directly into a SpEL expression so I wrote a simple bean that exposes a method for doing that (public String retrieveId(MessageHeaders headers)).

Then I tried to use the bean in my spring context file

    <!-- Helper beans -->
    <beans:bean id="messageIdentifier" class="ch.integration.jms.listener.model.MessageIdentifier"/>

...
    <!--  Dispatch message -->
    <file:outbound-gateway directory="file:${unmatchedMessageType.directory}"
        request-channel="unmatchedMessageTypeChannel" reply-channel="generatedFileChannel"
        filename-generator-expression="'${queue.jndi.name}' + '_' + @messageIdentifier.retrieveId(headers) + '.xml'"/>
...

But I got below error:

Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1057E:(pos 49): No bean resolver registered in the context to resolve access to bean 'messageIdentifier'
        at org.springframework.expression.spel.ast.BeanReference.getValueInternal(BeanReference.java:45)
        at org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:52)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:63)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:62)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:62)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:62)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:62)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:62)
        at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:93)
        at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:93)
        at org.springframework.integration.handler.LoggingHandler.handleMessageInternal(LoggingHandler.java:105)
        at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:73)
        ... 41 more

Any help is greatly appreciated.

Geetings
nuvola

[oleg.zhurakousky]

I think you are asking about Ternary operator with SpEL http://static.springsource.org/sprin....html#d0e12040
Let us know if that helped

[nuvola]

Thanks for the link about Ternary operator with SpEL.

I'm trying to use it as below:

    <int:logging-channel-adapter channel="bpListMessageTypeResultChannel"
        expression="'#### [Channel=bpListMessageTypeChannel][***' + (headers.MessageId != null) ? headers.MessageId : headers.jms_messageId + '][Headers=' + headers + '][Payload=' + payload + ']'"
      level="INFO"/>

but I got a type conversion problem so my above syntax is wrong ...

Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1001E:(pos 0): Type conversion problem, cannot convert from java.lang.String to java.lang.Boolean

An additional question. I need to use the same Ternary operator expression in more places in my spring context file, is there a way to store the result of the expression into a variable and reference it in the spring context file where it is needed ?

Thanks and regards
nuvola

[Cleric]

Hello

If you do this:

headers.MessageId != null ? headers.MessageId : headers.jms_messageId

it's enough to use an "Elvis Operator": http://static.springsource.org/sprin....html#d0e12053

headers.MessageId ?: headers.jms_messageId

Also try to wrap it with () as it should be done before String concatenation. That's why you've catched SpelEvaluationException

But what is a problem to use with <logging-channel-adapter> attribute log-full-message="true" ?

is there a way to store the result of the expression into a variable

Can you explain a bit more about use-case? If you plan to store result of SpEL around Message properties (payload & headers) it will be bad idea: Spring Integration has stateless programming model and invokes SpEL from 'expression' attributes at runtime for each Message.

Take care,
Artem Bilan

[nuvola]

Hi Artem,

your suggestion wrapping the expression with () works:

    <int:logging-channel-adapter channel="bpListMessageTypeResultChannel"
        expression="'#### [Channel=bpListMessageTypeChannel][' + (headers.MessageId ?: headers.jms_messageId) + '][Headers=' + headers + '][Payload=' + payload + ']'"
        level="INFO"/>

but it seems it doesn't work in case of stored-proc-outbound-gateway ...
I used the same expression in the below <int-jdbcarameter name="I_MSG_ID" expression="...":

    <int-jdbc:stored-proc-outbound-gateway request-channel="bpListMessageTypeChannel"
                                           reply-channel="bpListMessageTypeResultChannel"
                                           data-source="dataSource"
                                           stored-procedure-name="${stored-procedure-name.bp}"
                                           auto-startup="true"
                                           ignore-column-meta-data="true">
        <int-jdbc:sql-parameter-definition name="I_XML"
                                           direction="IN"
                                           type="VARCHAR"/>
        <int-jdbc:sql-parameter-definition name="I_MSG_ID"
                                           direction="IN"
                                           type="VARCHAR"/>
        <int-jdbc:sql-parameter-definition name="O_ERR_CODE"
                                           direction="OUT"
                                           type="INTEGER"/>
        <int-jdbc:parameter name="I_XML" expression="payload"/>
        <int-jdbc:parameter name="I_MSG_ID" expression="(headers.MessageId ?: headers.jms_messageId)"/>

but I got

Caused by: org.springframework.dao.InvalidDataAccessApiUsageException: Required input parameter 'I_MSG_ID' is missing
        at org.springframework.jdbc.core.CallableStatementCreatorFactory$CallableStatementCreatorImpl.createCallableStatement(CallableStatementCreatorFactory.java:209)
        at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:947)
        at org.springframework.jdbc.core.JdbcTemplate.call(JdbcTemplate.java:1003)
        at org.springframework.jdbc.core.simple.AbstractJdbcCall.executeCallInternal(AbstractJdbcCall.java:388)
        at org.springframework.jdbc.core.simple.AbstractJdbcCall.doExecute(AbstractJdbcCall.java:351)
        at org.springframework.jdbc.core.simple.SimpleJdbcCall.execute(SimpleJdbcCall.java:181)
        at org.springframework.integration.jdbc.StoredProcExecutor.executeStoredProcedure(StoredProcExecutor.java:276)
        at org.springframework.integration.jdbc.StoredProcExecutor.executeStoredProcedureInternal(StoredProcExecutor.java:267)
        at org.springframework.integration.jdbc.StoredProcExecutor.executeStoredProcedure(StoredProcExecutor.java:247)
        at org.springframework.integration.jdbc.StoredProcOutboundGateway.handleRequestMessage(StoredProcOutboundGateway.java:82)
        at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:97)
        at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:73)
        ... 28 more

Instead it is ok if I use <int-jdbcarameter name="I_MSG_ID" expression="headers.MessageId"/>

Does the expression syntax change in case of stored-proc-outbound-gateway ?

Thanks and regards
nuvola

[Cleric]

OK.

Try this one:

<int-jdbc:parameter name="I_MSG_ID" expression="headers['MessageId'] ?: headers['jms_messageId']"/>

[nuvola]

This works if the headers contain the property 'MessageId' otherwise I got an error

Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1008E:(pos 54): Field or property 'MessageId' cannot be found on object of type 'org.springframework.integration.MessageHeaders'
        at org.springframework.expression.spel.ast.PropertyOrFieldReference.readProperty(PropertyOrFieldReference.java:208)
        at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:72)
        at org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:57)
        at org.springframework.expression.spel.ast.Elvis.getValueInternal(Elvis.java:44)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:63)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:62)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:62)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:62)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:62)
        at org.springframework.expression.spel.ast.OpPlus.getValueInternal(OpPlus.java:62)
        at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:93)
        at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:93)
        at org.springframework.integration.handler.LoggingHandler.handleMessageInternal(LoggingHandler.java:105)
        at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:73)
        ... 41 more

I'm trying to work around your suggestion ...

[Cleric]

I still don't understand:
if you change SpEL from beanPropety style to map style it should work.
I've tested it before send you suggestion ;-).

So, I repeat: this should work:

<int-jdbc:parameter name="I_MSG_ID" expression="headers['MessageId'] ?: headers['jms_messageId']"/>

And in the <logging-channel-adapter> do the same, please

[nuvola]

If I change from beanPropety style to map style in both stored-proc-outbound-gateway and logging-channel-adapter it works

    <int-jdbc:stored-proc-outbound-gateway request-channel="bpListMessageTypeChannel"
...
        <int-jdbc:parameter name="I_XML" expression="payload"/>
        <int-jdbc:parameter name="I_MSG_ID" expression="headers['MessageId'] ?: headers['jms_messageId']"/>
    </int-jdbc:stored-proc-outbound-gateway>

    <int:channel id="bpListMessageTypeResultChannel"/>

    <int:logging-channel-adapter channel="bpListMessageTypeResultChannel"
        expression="'#### [Channel=bpListMessageTypeChannel][' + (headers['MessageId'] ?: headers['jms_messageId']) + '][Headers=' + headers + '][Payload=' + payload + ']'"
        level="INFO"/>

If I change only in the stored-proc-outbound-gateway I got the error.

So as you suggested I changed in both :-)