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Corticon Server: Integration & Deployment Guide : Integrating Corticon Decision Services : Invoking a Decision Service from a different Decision Service
 

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Invoking a Decision Service from a different Decision Service

You can use an extended operator or service call out to invoke a decision service that has its own vocabulary from within another decision service. The called decision service does not need to be on the same server. It can be executed in-process as shown below.
The following code example is an extended operator that uses in-process execution. You need to construct and pass in an XML SOAP message as the input. You also need to parse the response to extract the values of interest and any messages.
public class Corticon implements ICcStandAloneExtension{

/**
* callCorticon makes an in-process call to the specified decision service
* The decisionServicePath points to a Ruleflow file
* The XML request conforms to the WSDL for the decision service
* The return value is the XML response from the decision service
* @param decisionServiceName
* @param decisionServicePath
* @param XMLRequest
* @return
*/

public static String callCorticon(String decisionServiceName,
String decisionServicePath,
String XMLRequest, Boolean enableUpdate)
{int minPoolSize = 1;
int maxPoolSize = 1;
// boolean enableUpdate = true;
String msgStyle = ICcServer.XML_HIER_STYLE;
try {
ICcServer iServer = CcServerFactory.getCcServer();
if(!iServer.isDecisionServiceDeployed(decisionServiceName))
{
iServer.addDecisionService(decisionServiceName,
decisionServicePath, enableUpdate, minPoolSize,
maxPoolSize, msgStyle);
}
return ( "Corticon Result = " + iServer.execute(XMLRequest));
}
catch (Exception e) {return "Corticon call to " +
decisionServiceName + " failed" + e;
} //End of try call corticon
} // End of method callCorticon
Summary of steps in this example:
1. Create the payload
2. Create the HTTP request
3. Prepare the HTTP POST using Apache HTTP librariess
4. Display the request JSON (for debugging)
5. Invoke Corticon
6. Display the response JSON (for debugging)
7. Extract the results
8. Display debugging information
public class restInvocationTest {
public restInvocationTest() {
}
public static void main(String[] args) {
try {
executeREST();
} catch (Exception e) {
System.out.println(e.getMessage());
}
}
private static void executeREST() throws Exception
{
String ccServerURL = "corticon-demo.dyndns.org:8860/.../execute";

// 1. CREATE PAYLOAD:
//SQL to get values
JSONObject applicantJSON = new JSONObject();
// create a JSON object for the Applicant entity
applicantJSON.put("skydiver", "false");
// set its isSkydiver attribute
applicantJSON.put("age", "25");
// set its age attribute
JSONObject metadataJSON = new JSONObject();
// create a JSON object for metadata for Person
metadataJSON.put("#type", "Applicant");
// set its #type attribute to "Applicant"
applicantJSON.put("__metadata", metadataJSON);
// add the metadata object to the applicant object
JSONArray ccObjects = new JSONArray();
// create an array of JSON objects
ccObjects.put(applicantJSON);
// add the applicant to it
JSONObject ccRequestObj = new JSONObject();
// create a JSON request object
ccRequestObj.put("Objects", ccObjects);
// set its objects attribute to the array of ccObjects

// 2. CREATE HTTP REQUEST
HttpEntity ccRequestEntity = EntityBuilder.create()
.setContentType(ContentType.APPLICATION_JSON)
.setText(ccRequestObj.toString()).build();

// 3. PREPARE THE HTTP PPOST Using Apache HTTP libs
HttpClient client = HttpClientBuilder.create().build();
HttpPost post = new HttpPost(ccServerURL);
post.setHeader("dsname", "Skydiver");
// might also set version or effective date
post.setEntity(ccRequestEntity);

// 4. DISPLAY THE REQUEST JSON before invoking Corticon
(only needed for debugging)
// [this is to display the request on the console]
BufferedReader rd = new BufferedReader
(new InputStreamReader(post.getEntity().getContent()));
StringBuffer result = new StringBuffer();
String line = "";
while ((line = rd.readLine()) != null) {result.append(line);}
String postJSONString = result.toString();
System.out.println("\nccRequestObj.toString()
:\n"+ccRequestObj.toString()); // Payload

// 5. INVOKE CORTICON
HttpResponse response = client.execute(post);

// 6. DISPLAY THE RESPONSE JSON (only needed for debugging)
rd = new BufferedReader(new InputStreamReader(response.getEntity()
.getContent()));
result = new StringBuffer();
line = "";
while ((line = rd.readLine()) != null) {result.append(line);}
String responseJSONString = result.toString();

// 7. EXTRACT THE RESULTS: riskRating value from Corticon response JSON
JSONTokener tokener = new JSONTokener(responseJSONString);
JSONObject respJSON = new JSONObject(tokener);
JSONArray objects = respJSON.getJSONArray("Objects");
JSONObject messages = respJSON.getJSONObject("Messages");

// Get object values
String riskRating = objects.getJSONObject(0).getString("riskRating");
String age = objects.getJSONObject(0).getString("age");
String isSkydiver = objects.getJSONObject(0).getString("skydiver");

// Get message values
String message = messages.getJSONArray
("Message").getJSONObject(0).getString("text");
String severity = messages.getJSONArray
("Message").getJSONObject(0).getString("severity");
String entityRef = messages.getJSONArray
("Message").getJSONObject(0).getString("entityReference");

// Display results
System.out.println("\nRESULTS -----------------------------");
System.out.println("\nRisk: " + riskRating
+ " for age = " + age + " and skydiver = " + isSkydiver);
System.out.println("Message: " + message);
System.out.println("Severity: " + severity);
System.out.println("Entity Reference: " + entityRef);

// 8. DEBUGGING (only needed for debugging)
System.out.println("\nDEBUGGING ---------------------------");
System.out.println("\nccRequestObj.toString():\n"+ccRequestObj.toString()); // Payload
System.out.println("\nccRequestEntity.toString():\n"+
ccRequestEntity.toString()); // Request entity
System.out.println("\nRequestJSONString:\n" + postJSONString); // Request JSON
System.out.println("\nResponse:\n" + response.toString()); // Shows just a response summary NOT the response JSON
System.out.println("\nResponseJSONString:\n" + responseJSONString); // Response
You could pass multiple Person objects in a single payload but then you need to use the entityReference to ensure that the correct message is matched up with the corresponding Person. Also if the rules return multiple messages for a single Person then you will need to iterate over the messages to extract all of them.