How to register Handler

ajay · March 28, 2020, 1:16pm

Hi,
i want to start my process as soon as a mail is received. I got the connector example as https://github.com/camunda/camunda-bpm-mail/tree/master/examples/print-service

In HOw to use section is says to register handler

Can someone tell me how to register a handler in Camunda in step by step manner. Or any help or reference link

Thanks
Aj

aravindhrs · March 29, 2020, 11:50am

@ajay, The documentation itself has the example how to register the handler and start the service. Handler is nothing but a Consumer function for the function notificationService.registerMailHandler(...)

github.com

camunda/camunda-bpm-mail/blob/master/extension/core/src/main/java/org/camunda/bpm/extension/mail/notification/MailNotificationService.java

/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.camunda.bpm.extension.mail.notification;

import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.function.Consumer;

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MailNotificationService.java

 public void registerMailHandler(Consumer<Mail> consumer) {
  	MessageTransformationHandler handler = new MessageTransformationHandler(consumer,
    configuration.downloadAttachments(), configuration.getAttachmentPath());
    registerMessageHandler(handler);
 }

public void registerMailHandler(Consumer<Mail> consumer) will be decorated as like below. This is how handlers are registered and started:

configuration = MailConfigurationFactory.getConfiguration();
    notificationService = new MailNotificationService(configuration);

    notificationService.registerMailHandler(mail -> {
      runtimeService.startProcessInstanceByKey("printProcess",
          Variables.createVariables()
            .putValue("mail", mail)
            .putValue("invoice", getInvoicePath()));
    });

    notificationService.start();

Refer this example:

github.com

camunda/camunda-bpm-mail/blob/master/examples/print-service/src/main/java/org/camunda/bpm/extension/mail/example/PrintServiceProcessApplication.java

/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.camunda.bpm.extension.mail.example;

import java.io.File;
import java.net.URISyntaxException;
import java.net.URL;

import org.camunda.bpm.application.PostDeploy;
import org.camunda.bpm.application.PreUndeploy;

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ajay · March 30, 2020, 5:13am

Thanks @aravindhrs,

I registered my handler in the my main class extending ServletProcessApplication.
I am able to achieve what i required.

Thanks
Aj

Guddy · January 10, 2022, 12:06pm

@aravindhrs: I am a Camunda newbie… I have Camunda running under a Wildfly. I am not clear how (in which object / file) I have to enter / call the example handler? So where do I have to put the file “MailNotifiactionService.java” and where do I have to enter it, so that the Process Engine uses it?
And how do I access it in the start event of the Camunda workflow?
Thanks for a little support and sorry for the basic questions

Ingo_Richtsmeier · January 10, 2022, 1:36pm

Hi @Guddy,

if you are asking about the camunda-bpm-mail community extension, you can find the installation instruction for wildfly here: camunda-bpm-mail/shared-process-engine-wildfly.md at master · camunda-community-hub/camunda-bpm-mail · GitHub

Hope this helps, Ingo

Guddy · January 10, 2022, 2:06pm

Hi @Ingo_Richtsmeier . Thanks, the installation itself worked, the extension runs under Wildfly. Send mail and poll mail also works, but the “react on incoming mails” I have not yet got to run. I lack the knowledge where (in which script) I have to enter the following code:

configuration = MailConfigurationFactory.getConfiguration();
notificationService = new MailNotificationService(configuration);

notificationService.registerMailHandler(mail → {
runtimeService.startProcessInstanceByKey(“printProcess”,
Variables.createVariables()
.putValue(“mail”, mail)
.putValue(“invoice”, getInvoicePath()));
});

And how the start event in the modeler (listener) must look exactly at the end…

Guddy · January 11, 2022, 7:46am

I would like to make my question more specific: How do I bring the Java file: MailNotificationService.java into the Camunda engine, resp. into the mail engine? I have never done this before… what steps are needed for this in my Camunda wildfly environment?
thank you for some help

system · January 30, 2024, 12:18pm