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Getting all fields in a Java Delegate

jorell

Hello
We are trying use activiti as a webservice orchestration tool. We're trying to design a generic delegate in which we pass in a list of variables which can be used as parameters in the external service call within the delegate. If we use activiti:field elements to specify the the webservice parameters then it requires us to know the field names before hand (since the Expression object need to be named after the activiti:field names).
Is there a way from within the delegate to get all the activiti:field elements for the given task. This would allow us to code a generic delegate that can be used across our different process definitions.

As a side not: We also tried using IO Specification but it seems to not be supported yet in activiti delegates.
Thanks in advance for any help!

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trolltop

Hiya Jorell,
We are attempting the same sort of usage: generic Web Service delegate to handle calling out to a Service; parameterise the Web Service operation via expressions and property injection. I have hit a small wall however with regards to property injection (using Spring).

I have defined the following:
[application.properties]

<br>## &ndash; ABC Webservices<br>abc.webservice.service.soa.wsdl = "<a href="http://some.address.ours:9999/wisd/Services/SOA/this_service.wsdl" rel="nofollow noopener noreferrer">http://some.address.ours:9999/wisd/Services/SOA/this_service.wsdl</a>"<br>abc.webservice.service.soa.class = ours.address.some.workflow.service.CDRSOAService<br>abc.webservice.service.soa.port.class = ours.address.some.workflow.service.CDRSOAServicePort<br>abc.webservice.service.soa.operation.collection = cdrSOACollectionOperation<br>abc.webservice.service.soa.operation.classification = cdrSOAClassificationOperation<br><br><br>## &ndash; Database connection parameters<br>db.connection.driver = org.h2.Driver<br>db.connection.url = jdbc:h2:mem:activiti;DB_CLOSE_DELAY=1000<br>db.connection.username = sa<br>db.connection.password = <br>

[loader.bpmn]

<br>&nbsp;&nbsp;&nbsp; <serviceTask id="abcServiceCall" name="Request Load" activiti:class=ours.address.some.workflow.WebServiceDelegate"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <extensionElements><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:field name="wsdl"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:expression>${abc.webservice.service.soa.wsdl}</activiti:expression><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </activiti:field><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:field name="serviceClass"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:expression>${abc.webservice.service.soa.class}</activiti:expression><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </activiti:field><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:field name="portClass"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:expression>${abc.webservice.service.soa.port.class}</activiti:expression><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </activiti:field><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:field name="operation"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:expression>${abc.webservice.service.soa.operation.collection}</activiti:expression><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </activiti:field><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:field name="parameters"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:expression>${jobName},${invocationId},${fileLocation},${collectionStartDate}</activiti:expression><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </activiti:field><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </extensionElements><br>&nbsp;&nbsp;&nbsp; </serviceTask><br>

… and then in the Delegate
[WebServiceDelegate.java]

<br>public class WebServiceDelegate implements JavaDelegate {<br><br><br>&nbsp;&nbsp;&nbsp; private Expression&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; wsdl;<br>&nbsp;&nbsp;&nbsp; private Expression&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; serviceClass;<br>&nbsp;&nbsp;&nbsp; private Expression&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; portClass;<br>&nbsp;&nbsp;&nbsp; private Expression&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; operation;<br>&nbsp;&nbsp;&nbsp; private Expression&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; parameters;<br>&nbsp;&nbsp;&nbsp; private Expression&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; returnValue;<br>&nbsp;&nbsp;&nbsp; private Expression&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; interceptor;<br><br>&nbsp;&nbsp;&nbsp; @Override<br>&nbsp;&nbsp;&nbsp; public void execute(DelegateExecution execution) {<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; LOG.info("Processing web service request: operation[" + operation.getValue(execution) + "]");<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // .. parameters for operation<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; List<String> params = new ArrayList<>();<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if (null != parameters) {<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if (parameters.getValue(execution) instanceof String) {<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; extractStringParameters(execution, params);<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; String wsdlString = (String) wsdl.getValue(execution);<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; try {<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // .. client connection<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; LOG.info("Trying URL: " + wsdlString);<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; URL wsdlURL = new URL(wsdlString);<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // .. get Web Service access point and invocation port via Reflection<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Class<?> serviceClazz = Class.forName((String) serviceClass.getValue(execution));<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Object service;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // try {<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; service = serviceClazz.getConstructor(new Class[] { URL.class, String.class }).newInstance(wsdlURL, SERVICE_NAME);<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Object port = getServicePort(serviceClazz, service, (String) portClass.getValue(execution));<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // .. setup endpoint (if required) and invoke service<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if ((null != interceptor) && (null != interceptor.getValue(execution))) {<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ClientProxy.getClient(port).getEndpoint().getOutInterceptors().add((Interceptor) interceptor.getValue(execution));<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }<br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; String operationName = (String) operation.getValue(execution);<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; LOG.info("Requested operation: " + operationName);<br>&hellip;<br>

Our general approach is: for each web service operation required to support our process applications, specify a service task using property file definitions, and parameterise BPMN service task using these property definitions, and provide one generic delegate to handle all/most "web service" Service Tasks.

This may help what you are trying to achieve … however … the small wall!

I can get Spring to load the property definitions, but I cannot get them injected into the BPMN process definitions for Activiti to recognise. The stack trace I get is:

<br>org.activiti.engine.ActivitiException: Unknown property used in expression: ${abc.webservice.service.soa.operation.collection}<br> at org.activiti.engine.impl.el.JuelExpression.getValue(JuelExpression.java:53)<br> at au.edu.ncver.cdr.domain.workflow.AbcServiceDelegate.execute(WebServiceDelegate.java:39)<br> at org.activiti.engine.impl.delegate.JavaDelegateInvocation.invoke(JavaDelegateInvocation.java:34)<br> at org.activiti.engine.impl.delegate.DelegateInvocation.proceed(DelegateInvocation.java:37)<br> at org.activiti.engine.impl.delegate.DefaultDelegateInterceptor.handleInvocation(DefaultDelegateInterceptor.java:25)<br> at org.activiti.engine.impl.bpmn.behavior.ServiceTaskJavaDelegateActivityBehavior.execute(ServiceTaskJavaDelegateActivityBehavior.java:49)<br> at org.activiti.engine.impl.bpmn.behavior.ServiceTaskJavaDelegateActivityBehavior.execute(ServiceTaskJavaDelegateActivityBehavior.java:40)<br> at org.activiti.engine.impl.bpmn.helper.ClassDelegate.execute(ClassDelegate.java:116)<br> at org.activiti.engine.impl.pvm.runtime.AtomicOperationActivityExecute.execute(AtomicOperationActivityExecute.java:44)<br> at org.activiti.engine.impl.interceptor.CommandContext.performOperation(CommandContext.java:87)<br> at org.activiti.engine.impl.persistence.entity.ExecutionEntity.performOperationSync(ExecutionEntity.java:532)<br> at org.activiti.engine.impl.persistence.entity.ExecutionEntity.performOperation(ExecutionEntity.java:527)<br> at org.activiti.engine.impl.pvm.runtime.AtomicOperationTransitionNotifyListenerStart.eventNotificationsCompleted(AtomicOperationTransitionNotifyListenerStart.java:52)<br> at org.activiti.engine.impl.pvm.runtime.AbstractEventAtomicOperation.execute(AbstractEventAtomicOperation.java:56)<br> at org.activiti.engine.impl.interceptor.CommandContext.performOperation(CommandContext.java:87)<br> at org.activiti.engine.impl.persistence.entity.ExecutionEntity.performOperationSync(ExecutionEntity.java:532)<br> at org.activiti.engine.impl.persistence.entity.ExecutionEntity.performOperation(ExecutionEntity.java:527)<br>

Other info:

using JUnit 4 (@RunWith(SpringJUnit4ClassRunner.class)
process deployed using @Deployment(resources = { "application.properties", "workflow/loader.bpmn" })

Any ideas??

jbarrez

So do I understand you correctly that you want the values of the properties file to be injected into the delegate class?

I don't know if that's supported. Either way, a quick-hack could be to create a wrapper bean around it and reference that bean in the xml

trolltop

Thanks Joram,
I figured (after a bit of hair-pulling) that my approach was not possible. Will give the wrapper bean idea a go.

Cheers

trolltop

FYI …

Following Joram's advice, I have managed to get over the small wall with Spring and the generic WebService approach mentioned earlier.
My steps:
* the generic JavaDelegate class for handling all of our web service class as described above.
* a property-value based configuration bean - properties set by Spring from application.properties as above
[java]
@Getter
public class CollectionServiceConfiguration implements AbcServiceConfiguration {

    @Autowired(required = true)
    @Value("${abc.webservice.service.soa.wsdl}")
    private String wsdl;

    @Autowired(required = true)
    @Value("${abc.webservice.service.soa.class}")
    private String serviceClass;

    @Autowired(required = true)
    @Value("${abc.webservice.service.soa.port.class}")
    private String servicePortClass;

    @Autowired(required = true)
    @Value("${abc.webservice.service.soa.operation.collection}")
    private String serviceOperation;

}
[/java]
* bean definition in the Spring application context file:

<br>&nbsp;&nbsp;&nbsp; <bean id="collectionServiceConfiguration" class="ours.address.some.workflow.service.CollectionServiceConfiguration"/><br>

* and the service definition

<br>&nbsp;&nbsp;&nbsp; <serviceTask id="abcServiceCall" name="Request Load" activiti:class="ours.address.some.workflow.AbcServiceDelegate"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <extensionElements><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:field name="wsdl"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:expression>#{collectionServiceConfiguration.wsdl}</activiti:expression><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </activiti:field><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:field name="serviceClass"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:expression>#{collectionServiceConfiguration.serviceClass}</activiti:expression><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </activiti:field><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:field name="portClass"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:expression>#{collectionServiceConfiguration.servicePortClass}</activiti:expression><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </activiti:field><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:field name="operation"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:expression>#{collectionServiceConfiguration.serviceOperation}</activiti:expression><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </activiti:field><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:field name="parameters"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <activiti:expression>${jobName},${invocationId},${fileLocation},${collectionStartDate}</activiti:expression><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </activiti:field><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </extensionElements><br>&nbsp;&nbsp;&nbsp; </serviceTask><br>

All hooked up and loads fine in JUnit - gotta be happy with that

Hope this helps,

jbarrez

Awesome. Thanks for posting back your solution!