Executing ODM business rules by using a JavaCompute node

String odmServerPolicyName = "{myPolicyProject}:myODMServerPolicy";
MbODMServer odmServer = getODMServer(odmServerPolicyName);

This method initializes a connection to the ODM Rule Execution server, which must be running when the message flow that references the JavaCompute node is deployed or started. The getODMServer method can be called only from within the onSetup method. MbODMServer objects must not be shared between JavaCompute nodes and must not be cached for longer than the lifetime of the current node. MbODMServer objects that are obtained in the onSetup method can be used in the evaluate method to look up rulesets.

When an MbODMServer object has been retrieved, it can be used to retrieve a ruleset from the ODM server for execution when the message flow is running. To retrieve a ruleset, call the getRuleset method on the MbODMServer object and supply the fully qualified path to the ruleset, in the form '/RuleAppName/RuleAppVersion/rulesetName/rulesetVersion'. You can specify either a particular version or latest to use the most recent version. For example:

MbODMRuleset odmRuleset = odmServer.getRuleset("/myRuleApp/1.0/my_ruleset/1.0");

MbODMRuleset odmRuleset = odmServer.getRuleset("/myRuleApp/Latest/my_ruleset/latest");

MbODMRuleset odmRuleset = odmServer.getRuleset("/myRuleApp/1.0/my_ruleset/latest");

When it is first referenced, the Latest version of a ruleset or RuleApp is loaded and cached at the application level. As a result, all message flows and nodes inside the application have the same Latest version, regardless of when they are first referenced. The latest version is re-evaluated when the application is stopped and restarted.

The getRuleset method retrieves the ruleset from the ODM server and makes it available in the embedded rule engine, ready for execution.

Rulesets define ruleset parameters, which are used to pass data between the ruleset and the calling application. The ruleset can have parameters of type Java or XML, and rulesets that support both parameter types can be called from a JavaCompute node. If the ruleset has parameters of type Java, the classes that define the Java objects for those parameters must be made available to the JavaCompute node at development time and at runtime. If you use the JavaCompute node wizard to query the ODM server and generate template Java code, you also have the option of downloading the class files that define the parameters and make them available to the Java project that contains the JavaCompute node.

The getRuleset method can be called during the JavaCompute node's onSetup or evaluate methods, and if the same rule is requested multiple times, all calls after the first one return the version that has been downloaded and cached. MbODMRuleset objects must not be shared between JavaCompute nodes and must not be cached for longer than the lifetime of the current node. MbODMRulesets can be retrieved during a JavaCompute node's onSetup method and then used by its evaluate method, to avoid delaying the execution of the first message.

When executing a ruleset, you must build up a map of parameters to supply to the execute method of the MbODMRuleset. The map must contain an entry for each parameter defined as an IN or INOUT parameter in the ruleset definition. For parameters of type XML, you must supply a Java string that contains an XML representation of the xsd type (simple or complex) defined for that parameter. For parameters of type Java, you must supply an instance of the Java class defined for that parameter. To execute the ruleset, call the execute method of the MbODMRuleset, passing in the map of parameters:

Map<String, Object> ruleInParameters = new HashMap<String, Object>();
MyObject myObj1 = new MyObject();
ruleInParameters.put("ruleParameter_Java_1", myObj1);
ruleInParameters.put("ruleParameter_XML_2", "<Customer><name>John Doe</name><age>33</age></Customer>");
MbODMRulesetExecutionResponse ruleResponse = odmRuleset.execute(ruleInParameters);

The result of calling the execute method is an instance of an MbODMRulesetExecutionResponse. This object gives access to the map of OUT and INOUT parameters of the ruleset through the getOutputParameters method, and to some execution statistics:

Map<String, Object> ruleOutParameters = ruleResponse.getOutputParameters();
MyResultObject myResult1 = (MyResultObject)ruleOutParameters.get("ruleResponseParameter1");
long rulesFired = ruleResponse.getTotalRulesFired();

You can use normal message tree access and modification techniques to retrieve data from the incoming message tree to build the parameters supplied to the ruleset execute method, and to build or modify the outgoing message tree with details from the result parameters. The execute method of the MbODMRuleset can be called multithreaded, and it does not need to be looked up for each flow instance.

When you create a JavaCompute node, you are presented with a series of templates, one of which is Process via Operational Decision Manager ruleset. Select this option to query the available rulesets in an ODM Rule Execution server; the wizard guides you through selecting a ruleset and then generates template Java code with details about the rule and how to call it. For more information, see Creating ODM classes by using the Process via Operational Decision Manager ruleset wizard.