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Loan Broker BPM Example

The BPM example illustrates using a business process engine (JBoss jBPM) to orchestrate the loan broker application. Observe how the process flow and decision logic are cleanly defined in a process definition file (which could be created and maintained using a GUI process editor), while the systems integration and messaging is handled by Mule.

Running the example

  1. Make sure you have met the prerequisites and installed Mule according to the [instructions].

  2. At the command line, navigate to the examples/loanbroker-bpm directory under your Mule home directory.

  3. Copy the pre-built example zip to the applications folder ($MULE_HOME/apps) and start Mule if it isn’t already started.

  4. Go to the following URI in your browser to send a loan request (there are some default request values built-in): http://localhost:12081

  5. In the Mule log file, you should see the process execute and a response message such as the following from one of the banks:

     Returning Rate is: ABigBank, rate: 6.379575743481158

  6. Now, modify the loan amount requested, and see different banks responding based on the amount: http://localhost:12081/?amount=100

  7. Try different amounts (100, 10000, 20000). Also try invalid numbers to see the error handling in action.

Building the example

Run mvn from the example source folder. This will compile the example classes, produce an application zip file and copy it to $MULE_HOME/apps.

Walking through the Mule Configuration

At the heart of the configuration is a Business Process Engine which receives and sends Mule messages. The messages which are received will start or advance a process execution, and the process execution will send messages to Mule endpoints.

Process Engine Receives and Generates Events

<flow name="ToBPMS">    <composite-source>        <inbound-endpoint ref="CustomerRequests" />        <inbound-endpoint ref="CreditProfiles" />    </composite-source>    <bpm:process processName="LoanBroker" processDefinition="loan-broker-process.jpdl.xml" /></flow>

The Process Engine is an instance of JBoss jBPM and is configured using defaults as follows. For more information refer to the BPM Module Reference documentation.

jBPM Process Engine

<bpm:jbpm name="jbpm" />

Walking Through the jBPM Process

The first message to arrive at the BPM process will be a customer request for a loan. This message triggers the BPMS to start a new instance of the "LoanBroker" process. The message payload will be stored into the customerRequest process variable.

Start State

<mule-receive name="incomingCustomerRequest" endpoint="CustomerRequests" var="customerRequest">

The next step is to send the customer’s information to the credit agency and get their credit report. The payload that we send to the credit agency comes from the customerRequest we just stored as a process variable.

Generate a Message to Credit Agency

<mule-send name="sendToCreditAgency" expr="#{customerRequest.customer}" endpoint="CreditAgency" synchronous="false">

The request to the credit agency is asynchronous, so we now transition to a wait state until a response from the credit agency is received. Note that if a response is not received within four hours, the process times out and requires manual intervention.

Wait state

<mule-receive name="waitForCreditAgency" endpoint="CreditProfiles" var="creditProfile">    <timer duedate="4 hours" />

Once a message is received from the credit agency, the next step prepares a loan request based on the two pieces of information we have received thus far (customerRequest and creditProfile). This invokes a POJO method using jPDL’s standard <java> activity.

Prepare Loan Quote Request

<java name="prepareLoanQuoteRequest" class="org.mule.example.loanbroker.bpm.activity.PrepareLoanQuoteRequest" method="prepareRequest" var="loanRequest">    <arg><object expr="#{customerRequest}"/></arg>    <arg><object expr="#{creditProfile}"/></arg>    <transition to="sendToBanks" /></java>

Now for the interesting part: the process itself decides which of the three banks, if any, to request a loan from on behalf of this customer. The loan amount, customer’s credit history, and credit score are all taken into account. If the customer would not qualify for a loan from any of the three banks based on these criteria, the loan is denied.

Decision Node

<decision name="sendToBanks">    <transition to="sendToBigBank">        <condition expr="#{customerRequest.loanAmount >= 20000}" />        <condition expr="#{creditProfile.creditHistory >= 24}" />        <condition expr="#{creditProfile.creditScore >= 5}" />    </transition>    <transition to="sendToMediumBank">        <condition expr="#{customerRequest.loanAmount >= 10000}" />        <condition expr="#{creditProfile.creditHistory >= 12}" />        <condition expr="#{creditProfile.creditScore >= 3}" />    </transition>    <transition to="sendToSmallBank">        <condition expr="#{creditProfile.creditHistory >= 6}" />        <condition expr="#{creditProfile.creditScore >= 1}" />    </transition>    <!-- If the credit info. doesn't meet minimum requirements based on the loan amount, the loan is just denied. -->    <transition to="loanDenied" /></decision>

The final loan quote from the bank is validated and sent back to the customer, and the process ends up in one of two end states: loanApproved or loanDenied, depending on the outcome.

Send Final Response and End Process

<mule-send name="sendCustomerResponse" expr="#{loanQuote}" endpoint="CustomerResponses">    <transition to="loanApproved" /></mule-send>  <end name="loanApproved" /><end name="loanDenied" />