[so.git] /

/*-
 * ============LICENSE_START=======================================================
 * ONAP - SO
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * Modifications Copyright (c) 2019 Samsung
 * ================================================================================
 * 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.
 * ============LICENSE_END=========================================================
 */

package org.onap.so.bpmn.core.plugins;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import org.camunda.bpm.engine.delegate.BpmnError;
import org.camunda.bpm.engine.delegate.DelegateExecution;
import org.camunda.bpm.engine.delegate.ExecutionListener;
import org.camunda.bpm.engine.delegate.JavaDelegate;
import org.camunda.bpm.engine.impl.bpmn.behavior.ClassDelegateActivityBehavior;
import org.camunda.bpm.engine.impl.bpmn.parser.AbstractBpmnParseListener;
import org.camunda.bpm.engine.impl.bpmn.parser.BpmnParseListener;
import org.camunda.bpm.engine.impl.cfg.AbstractProcessEnginePlugin;
import org.camunda.bpm.engine.impl.cfg.ProcessEngineConfigurationImpl;
import org.camunda.bpm.engine.impl.persistence.entity.ProcessDefinitionEntity;
import org.camunda.bpm.engine.impl.pvm.PvmTransition;
import org.camunda.bpm.engine.impl.pvm.process.ActivityImpl;
import org.camunda.bpm.engine.impl.pvm.process.TransitionImpl;
import org.camunda.bpm.engine.impl.util.xml.Element;
import org.onap.so.bpmn.core.WorkflowException;
import org.springframework.stereotype.Component;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This plugin does the following:
 * <ol>
 * <li>Adds logic at the start of every Call Activity to remove any existing WorkflowException object from the execution
 * (saving a copy of it in a different variable).</li>
 * <li>Adds logic at the end of every Call Activity to generate a MSOWorkflowException event if there is a
 * WorkflowException object in the execution.</li>
 * </ol>
 */
@Component
public class WorkflowExceptionPlugin extends AbstractProcessEnginePlugin {
    private static final Logger logger = LoggerFactory.getLogger(WorkflowExceptionPlugin.class);

    private static final String WORKFLOW_EXCEPTION = "WorkflowException";

    @Override
    public void preInit(ProcessEngineConfigurationImpl processEngineConfiguration) {
        List<BpmnParseListener> preParseListeners = processEngineConfiguration.getCustomPreBPMNParseListeners();

        if (preParseListeners == null) {
            preParseListeners = new ArrayList<>();
            processEngineConfiguration.setCustomPreBPMNParseListeners(preParseListeners);
        }

        preParseListeners.add(new WorkflowExceptionParseListener());
    }

    public static class WorkflowExceptionParseListener extends AbstractBpmnParseListener {
        @Override
        public void parseProcess(Element processElement, ProcessDefinitionEntity processDefinition) {
            AtomicInteger triggerTaskIndex = new AtomicInteger(1);
            List<ActivityImpl> activities = new ArrayList<>(processDefinition.getActivities());
            recurse(activities, triggerTaskIndex);
        }

        /**
         * Helper method that recurses (into subprocesses) over all the listed activities.
         * 
         * @param activities a list of workflow activities
         * @param triggerTaskIndex the index of the next trigger task (mutable)
         */
        private void recurse(List<ActivityImpl> activities, AtomicInteger triggerTaskIndex) {
            for (ActivityImpl activity : activities) {
                String type = (String) activity.getProperty("type");

                if ("callActivity".equals(type)) {
                    // Add a WorkflowExceptionResetListener to clear the WorkflowException
                    // variable when each Call Activity starts.

                    activity.addListener(ExecutionListener.EVENTNAME_START, new WorkflowExceptionResetListener());

                    // Add a WorkflowExceptionTriggerTask after the call activity.
                    // It must be a task because a listener cannot be used to generate
                    // an event. Throwing BpmnError from an execution listener will
                    // cause the process to die.

                    List<PvmTransition> outTransitions = new ArrayList<>(activity.getOutgoingTransitions());

                    for (PvmTransition transition : outTransitions) {
                        String triggerTaskId = "WorkflowExceptionTriggerTask_" + triggerTaskIndex;

                        ActivityImpl triggerTask = activity.getFlowScope().createActivity(triggerTaskId);

                        ClassDelegateActivityBehavior behavior = new ClassDelegateActivityBehavior(
                                WorkflowExceptionTriggerTask.class.getName(), new ArrayList<>(0));

                        triggerTask.setActivityBehavior(behavior);
                        triggerTask.setName("Workflow Exception Trigger Task " + triggerTaskIndex);
                        triggerTaskIndex.getAndIncrement();

                        TransitionImpl transitionImpl = (TransitionImpl) transition;
                        TransitionImpl triggerTaskOutTransition = triggerTask.createOutgoingTransition();
                        triggerTaskOutTransition.setDestination((ActivityImpl) transitionImpl.getDestination());
                        transitionImpl.setDestination(triggerTask);
                    }
                } else if ("subProcess".equals(type)) {
                    recurse(new ArrayList<>(activity.getActivities()), triggerTaskIndex);
                }
            }
        }
    }

    /**
     * If there is a WorkflowException object in the execution, this method removes it (saving a copy of it in a
     * different variable).
     */
    public static class WorkflowExceptionResetListener implements ExecutionListener {
        public void notify(DelegateExecution execution) throws Exception {
            Object workflowException = execution.getVariable(WORKFLOW_EXCEPTION);

            if (workflowException instanceof WorkflowException) {
                int index = 1;
                String saveName = "SavedWorkflowException" + index;
                while (execution.getVariable(saveName) != null) {
                    saveName = "SavedWorkflowException" + (++index);
                }

                logger.debug("WorkflowExceptionResetTask is moving WorkflowException to {}", saveName);

                execution.setVariable(saveName, workflowException);
                execution.setVariable(WORKFLOW_EXCEPTION, null);
            }
        }
    }

    /**
     * Generates an MSOWorkflowException event if there is a WorkflowException object in the execution.
     */
    public static class WorkflowExceptionTriggerTask implements JavaDelegate {
        public void execute(DelegateExecution execution) throws Exception {
            if (execution.getVariable(WORKFLOW_EXCEPTION) instanceof WorkflowException) {
                logger.debug("WorkflowExceptionTriggerTask is generating a MSOWorkflowException event");
                throw new BpmnError("MSOWorkflowException");
            }
        }
    }
}