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Allows Mule events to initiate and/or advance processes in an external or embedded Business Process Management System (BPMS). It also allows executing processes to generate Mule events.
/*
* Copyright (c) MuleSoft, Inc. All rights reserved. http://www.mulesoft.com
* The software in this package is published under the terms of the CPAL v1.0
* license, a copy of which has been included with this distribution in the
* LICENSE.txt file.
*/
package org.mule.module.bpm;
import org.mule.DefaultMuleEvent;
import org.mule.DefaultMuleMessage;
import org.mule.MessageExchangePattern;
import org.mule.VoidMuleEvent;
import org.mule.RequestContext;
import org.mule.api.MuleContext;
import org.mule.api.MuleEvent;
import org.mule.api.MuleException;
import org.mule.api.MuleMessage;
import org.mule.api.config.MuleProperties;
import org.mule.api.construct.FlowConstruct;
import org.mule.api.endpoint.EndpointCache;
import org.mule.api.endpoint.OutboundEndpoint;
import org.mule.api.lifecycle.Disposable;
import org.mule.api.lifecycle.Initialisable;
import org.mule.api.lifecycle.InitialisationException;
import org.mule.api.transport.DispatchException;
import org.mule.api.transport.PropertyScope;
import org.mule.config.i18n.MessageFactory;
import org.mule.endpoint.SimpleEndpointCache;
import org.mule.transport.NullPayload;
import org.mule.util.StringUtils;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* A business process definition.
*/
public class Process implements Initialisable, Disposable, MessageService
{
/** The underlying BPMS */
private final BPMS bpms;
/** The logical name of the process. This is used to look up the running process instance from the BPMS. */
private final String name;
/** The resource containing the process definition. This will be used to deploy the process to the BPMS. */
private final String resource;
/** This field will be used to correlate messages with processes. */
protected final String processIdField;
protected MuleContext muleContext;
/** Needed for exception handling. */
private FlowConstruct flowConstruct;
public static final String BPM_PROPERTY_PREFIX = "BPM_";
public static final String PROPERTY_ENDPOINT =
MuleProperties.PROPERTY_PREFIX + BPM_PROPERTY_PREFIX + "ENDPOINT";
public static final String PROPERTY_PROCESS_TYPE =
MuleProperties.PROPERTY_PREFIX + BPM_PROPERTY_PREFIX + "PROCESS_TYPE";
public static final String PROPERTY_PROCESS_ID =
MuleProperties.PROPERTY_PREFIX + BPM_PROPERTY_PREFIX + "PROCESS_ID";
public static final String PROPERTY_ACTION =
MuleProperties.PROPERTY_PREFIX + BPM_PROPERTY_PREFIX + "ACTION";
public static final String PROPERTY_TRANSITION =
MuleProperties.PROPERTY_PREFIX + BPM_PROPERTY_PREFIX + "TRANSITION";
public static final String PROPERTY_PROCESS_STARTED =
MuleProperties.PROPERTY_PREFIX + BPM_PROPERTY_PREFIX + "STARTED";
public static final String ACTION_START = "start";
public static final String ACTION_ADVANCE = "advance";
public static final String ACTION_UPDATE = "update";
public static final String ACTION_ABORT = "abort";
public static final String PROCESS_VARIABLE_INCOMING = "incoming";
public static final String PROCESS_VARIABLE_INCOMING_SOURCE = "incomingSource";
public static final String PROCESS_VARIABLE_DATA = "data";
protected static final Log logger = LogFactory.getLog(Process.class);
private final EndpointCache endpointCache;
public Process(BPMS bpms, String name, String resource, FlowConstruct flowConstruct, MuleContext muleContext)
{
this(bpms, name, resource, null, flowConstruct, muleContext);
}
public Process(BPMS bpms, String name, String resource, String processIdField, FlowConstruct flowConstruct, MuleContext muleContext)
{
this.bpms = bpms;
this.name = name;
this.resource = resource;
this.processIdField = processIdField;
this.flowConstruct = flowConstruct;
this.muleContext = muleContext;
this.endpointCache = new SimpleEndpointCache(muleContext);
}
public void initialise() throws InitialisationException
{
try
{
bpms.deployProcess(resource);
}
catch (Exception e)
{
throw new InitialisationException(e, this);
}
}
public void dispose()
{
try
{
bpms.undeployProcess(resource);
}
catch (Exception e)
{
logger.warn(e.getMessage());
}
}
protected Object handleEvent(MuleEvent event) throws Exception
{
// An object representing the new state of the process
Object process;
// Create a map of process variables based on the message properties.
Map processVariables = new HashMap();
if (event != null && !VoidMuleEvent.getInstance().equals(event))
{
populateProcessVariables(event, processVariables, PropertyScope.INVOCATION);
populateProcessVariables(event, processVariables, PropertyScope.INBOUND);
Object payload = event.getMessage().getPayload();
if (payload != null && !(payload instanceof NullPayload))
{
// Store the message's payload as a process variable.
processVariables.put(PROCESS_VARIABLE_INCOMING, payload);
// Store the endpoint on which the message was received as a process variable.
String originatingEndpoint = event.getMessage().getInboundProperty(MuleProperties.MULE_ORIGINATING_ENDPOINT_PROPERTY);
if (StringUtils.isNotEmpty(originatingEndpoint))
{
processVariables.put(PROCESS_VARIABLE_INCOMING_SOURCE, originatingEndpoint);
}
}
}
String processIdField = getProcessIdField();
if (StringUtils.isEmpty(processIdField))
{
processIdField = PROPERTY_PROCESS_ID;
}
Object processId;
processId = event.getMessage().getSessionProperty(processIdField);
if (processId == null)
{
processId = event.getMessage().getInvocationProperty(processIdField);
}
if (processId == null)
{
processId = event.getMessage().getInboundProperty(processIdField);
}
processVariables.remove(processIdField);
// Default action is "advance"
String action = event.getMessage().getInvocationProperty(PROPERTY_ACTION, ACTION_ADVANCE);
processVariables.remove(PROPERTY_ACTION);
Object transition = event.getMessage().getInvocationProperty(PROPERTY_TRANSITION);
processVariables.remove(PROPERTY_TRANSITION);
// //////////////////////////////////////////////////////////////////////
logger.debug("Message received: payload = " + event.getMessage().getPayload().getClass().getName() + " processType = " + name + " processId = " + processId + " action = " + action);
// Start a new process.
if (processId == null || action.equals(ACTION_START))
{
process = getBpms().startProcess(name, transition, processVariables);
if ((process != null) && logger.isInfoEnabled())
{
logger.info("New process started, ID = " + getBpms().getId(process));
}
}
// Don't advance the process, just update the process variables.
else if (action.equals(ACTION_UPDATE))
{
if (processId != null)
{
process = getBpms().updateProcess(processId, processVariables);
if ((process != null) && logger.isInfoEnabled())
{
logger.info("Process variables updated, ID = " + getBpms().getId(process));
}
}
else
{
throw new IllegalArgumentException("Process ID is missing, cannot update process.");
}
}
// Abort the running process (end abnormally).
else if (action.equals(ACTION_ABORT))
{
if (processId != null)
{
getBpms().abortProcess(processId);
process = NullPayload.getInstance();
logger.info("Process aborted, ID = " + processId);
}
else
{
throw new IllegalArgumentException("Process ID is missing, cannot abort process.");
}
}
// Advance the already-running process one step.
else
{
if (processId != null)
{
process = getBpms().advanceProcess(processId, transition, processVariables);
if ((process != null) && logger.isInfoEnabled())
{
logger.info("Process advanced, ID = " + getBpms().getId(process)
+ ", new state = " + getBpms().getState(process));
}
}
else
{
throw new IllegalArgumentException("Process ID is missing, cannot advance process.");
}
}
return process;
}
protected void populateProcessVariables(MuleEvent event, Map processVariables, PropertyScope propertyScope)
{
for (String propertyName : event.getMessage().getPropertyNames(propertyScope))
{
// The session property can become rather large and causes problems with DB persistence.
if (!propertyName.equals(MuleProperties.MULE_SESSION_PROPERTY))
{
processVariables.put(propertyName, event.getMessage().getProperty(propertyName, propertyScope));
}
}
}
// TODO This method should probably use the LocalMuleClient instead of re-inventing the wheel
public MuleMessage generateMessage(String endpoint, Object payload, Map messageProperties, MessageExchangePattern exchangePattern) throws MuleException
{
MuleMessage message;
if (payload instanceof MuleMessage)
{
message = (MuleMessage) payload;
}
else
{
message = new DefaultMuleMessage(payload, muleContext);
}
message.addProperties(messageProperties, PropertyScope.OUTBOUND);
message.addProperties(messageProperties, PropertyScope.INVOCATION);
// Use an endpoint cache to prevent memory leaks (see MULE-5422)
OutboundEndpoint ep = endpointCache.getOutboundEndpoint(endpoint, exchangePattern, null);
DefaultMuleEvent event = new DefaultMuleEvent(message, ep.getExchangePattern(), flowConstruct);
RequestContext.setEvent(event);
// Set correlation properties in SESSION scope so that they get propagated to response messages.
if (messageProperties.get(PROPERTY_PROCESS_TYPE) != null)
{
event.getMessage().setSessionProperty(PROPERTY_PROCESS_TYPE, messageProperties.get(PROPERTY_PROCESS_TYPE));
}
if (messageProperties.get(PROPERTY_PROCESS_ID) != null)
{
event.getMessage().setSessionProperty(PROPERTY_PROCESS_ID, messageProperties.get(PROPERTY_PROCESS_ID));
}
MuleEvent resultEvent = ep.process(event);
MuleMessage response = null;
if (resultEvent != null && !VoidMuleEvent.getInstance().equals(resultEvent))
{
response = resultEvent.getMessage();
if (response.getExceptionPayload() != null)
{
throw new DispatchException(MessageFactory.createStaticMessage("Unable to send or route message"), event, ep, response.getExceptionPayload().getRootException());
}
}
return response;
}
public String getProcessIdField()
{
return processIdField;
}
public BPMS getBpms()
{
return bpms;
}
public String getResource()
{
return resource;
}
public String getName()
{
return name;
}
}