How to invoke a web service from a Workflow Method

PSkalka

Hello,

I am working on a BPM process.

In an automatic activity, I need to invoke an external web service.

I am extending WorkflowMethod abstract class and overriding the doTask method.

In this method, I have the following code fragment:

URL wsdlUrl = new URL("file:" + wsdlLocation);

QName qname = new QName(qnameNameSpaceUri, qnameLocalPart);

SpazioServiceService sss = new SpazioServiceService(wsdlUrl, qname);

SpazioService ssp = sss.getSpazioServicePort();

String intNum = ssp.send(queueManager,

queue,

filePath,

fileName,

sender,

uclass);

The proxy has been generated by Axis.

At runtime, I get the following error:

java.lang.LinkageError: loader constraint violation: when resolving method "javax.xml.ws.Service.<init>(Ljava/net/URL;Ljavax/xml/namespace/QName;)V" the class loader (instance of java/net/URLClassLoader) of the current class, it/equitaliaservizi/pcs/spazio/services/SpazioServiceService, and the class loader (instance of <bootloader>) for resolved class, javax/xml/ws/Service, have different Class objects for the type javax/xml/namespace/QName used in the signature

at it.equitaliaservizi.pcs.spazio.services.SpazioServiceService.<init>(SpazioServiceService.java:42)

at it.equitaliaservizi.pcs.dctm.spazio.SpazioWriteFlussoFisico.doTask(SpazioWriteFlussoFisico.java:92)

at com.documentum.bpm.rtutil.WorkflowMethod.execute(WorkflowMethod.java:214)

at com.documentum.bpm.rtutil.AbstractWorkflowMethod.executeMethod(AbstractWorkflowMethod.java:27)

at com.documentum.bpm.rtutil.GenericWorkflowMethod.execute(GenericWorkflowMethod.java:124)

at com.documentum.bpm.rtutil.GenericWorkflowMethod.execute(GenericWorkflowMethod.java:65)

at com.documentum.mthdservlet.DfMethodRunner.runIt(Unknown Source)

at com.documentum.mthdservlet.AMethodRunner.runAndReturnStatus(Unknown Source)

at com.documentum.mthdservlet.DoMethod.invokeMethod(Unknown Source)

at com.documentum.mthdservlet.DoMethod.doPost(Unknown Source)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)

at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)

at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)

at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)

at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)

at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)

at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)

at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)

at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)

at java.lang.Thread.run(Thread.java:662)

So I would like to know which is the best practice to implement a client.

I have:

- Java Method Server on jBoss 5.1.0

- JRE 1.6.0_27

I was not able to find any guideline or tutorial about web service invocation from a BPM workflow method.

Does anybody have any suggestion?

Thanks in advance

Pawel

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leonardo.marini@gmail.com

Hi PSkalka,

did you finally solved ? I have the same requirement and same issue you have.

Thanks

Leo

PSkalka

Hi Leonardo,

actually I have found some kind of workaround... I am not sure if it is a best practice but, finally, it is working for me.

In my own development environment (xCP 1.6, jBoss 4.3.0), I have used BOFs.

That means: I have created a Composer project, I have defined JAR Definition artifacts, one for each JAR I need to use; then I have defined Java Library artifacts, each one "containing" all of the needed JARs.

Then I have created Module (simple module, not aspect module) artifacts; in the deployment tab, I have added the required Java Library artifacts.

Finally, I have created a Method artifact to invoke the web service and do the rest of the job. In my method verb, I have called the Module.

After that, this does perfectly work in my development environment.

When I deployed all that stuff to the customer's staging environment, it did not work. I incurred into "ClassNotDefined" errors or something similar. It seems that the jBoss Java Method Server (jBoss 5.1.0) in the staging environment does not load client classes from BOFs, due to some configuration issue I was not able to solve.

The final workaround has been to:

1) stop the java method server

2) deploy my needed JARs into the lib folder of the java method server (for example: /opt/documentum/dctm_shared/jbossN.M.X/server/DctmServer_MethodServer/lib)

3) start the java method server

I don't like this, but it is working. I had no time to investigate further, I hope I will do it later.

Hope this helps.

Best regards

Pawel

leonardo.marini@gmail.com

Are you still extending WorkflowMethod abstract class and overriding the doTask method in your solution ? If so I think that should be some extra configuration that i miss since that class is not on classpath. I added the relevant jar to that location but now the doTask method is not invoked and the server expects a class implementing IDmMethod.

Can you please provide your solution template ?

Thanks in advance,

Leo

PSkalka

Hi,

sorry, I can't publish the solution, and I cannot clean the code right now.

I will explain the main concepts at least.

First of all, somewhere I have read that IDmMethod is somehow deprecated, it is better to implement IDfMethod.

So my class declaration for a Method is:

public class MyMethod implements IDfMethod, IDfModule

and I override

public int execute(Map parameters, PrintWriter pw)

for a Workflow Method it is:

public class MyWorkflowMethod extends WorkflowMethod implements IDfMethod, IDfModule

and I override

protected int doTask(IDfWorkitem workitem, IDfProperties activityParameters, PrintWriter pw)

As I create a new java project, I always add these jars to the project's build path:

bpm_infra.jar
bpmutil.jar
dfc.jar

Please note that I DO NOT deploy them to the target environment, they are already deployed with some server component, I only need them in my development environment to compile and to work gracefully with code completion and so on.

You should check what I have wrote on your server version. I have been working with content server 6.5, 6.7, never with older versions. bpm_infra.jar and bpmutil.jar can be found in some /lib folder on your server.

leonardo.marini@gmail.com

I need to call the method in a workflow so my class declaration looks like this:

public class MyWorkflowMethod extends WorkflowMethod implements IDfMethod, IDfModule .

I have removed the IDfModule interface and declared the java class in the method verb since I understood you are not using the BOF way (is it ?).

I have placed required jars into DctmServer_MethodServer/lib but when I run the workflow I have other problems ( the server is looking for an IDmMethod implementation ).

Since I work with server version 6.7 I just think that something on method configuration is different (I mean checkboxes in method configuration and bof name or java class in the method verb ).

Thank you again for your support.

Leo

PSkalka

Well,

please let me recap.

I have a workflow method too.

In my case, for example, I have this class declaration:

package mypackage;

public class StartJobXml extends WorkflowMethod implements IDfMethod, IDfModule {

My method is:

@Override

protected int doTask(IDfWorkitem workitem, IDfProperties activityParameters, PrintWriter pw) throws Exception {

In Composer, my project has got:

1 jar definition (implementation jar, not interface jar!) for each required jar (my StartJobXml class, + httpclient, + axis libraries if required and so on)
some java libraries to collect the required jar definitions (1 for all httpclient jars, for example)
1 module (it goes with 1 implementation jar, main class is mypackage.StartJobXml, + my java libraries added to the deployment tab)
1 method, having the following checkboxes checked: "run as the server", "use method server", "launch directly", "use as workflow method". the method verb command is just the module's name

In my process template, of course, the custom activity calls the custom java method.

- everything is deployed via DAR installation, nothing goes into dba/java_methods as somebody used to do (me too), no server restart required.

- just, as I told before, in customer's environment I was forced to deploy some libraries (httpclient, or axis) into the DctmServer_MethodServer/lib folder manually and restart.

It is working, on 6.7.

Please have a look to this link: http://beachstreetblog.wordpress.com/2010/02/01/custom-activities-in-xcp/

I can't tell why are you experiencing that wrong expectation by the server...

leonardo.marini@gmail.com

Now I've undestood the solution you adopted and it is far away from the one implemented by me.

Thank you very much !!!

Leo

leonardo.marini@gmail.com

As long as I can see jax-ws is not working and this is caused by documentum Java Method Server applications violating JBoss class loader policy.

Everything goes fine if I use Axis as web service client (no extra configurations just axis jar packaged with module).

Thank's againg for your support.