package ca.uhn.hl7v2.validation.app;
import org.apache.log4j.NDC;
import org.slf4j.LoggerFactory;
import ca.uhn.hl7v2.HL7Exception;
import ca.uhn.hl7v2.model.Message;
import ca.uhn.hl7v2.model.Segment;
import ca.uhn.hl7v2.parser.PipeParser;
import ca.uhn.hl7v2.util.Terser;
/**
* An application intended for testing messages. The intended use is to route a copy
* of (selected) messages to a test application, which identifies and acts on problems independently
* of the normal error acknowledgement path (for example by notifying an administrator).
* This makes the most sense when used within an interface engine, for example if the
* sending nor receiving system use HAPI, but it is desired to route messages to HAPI in
* parallel so that they can be fully validated.
* @author Bryan Tripp
*/
public abstract class TestApplication implements ca.uhn.hl7v2.app.Application {
private PipeParser parser;
/** Creates a new instance of TestApplication */
public TestApplication() {
parser = new PipeParser();
}
/**
* Returns true if this Application wishes to accept the message. By returning
* true, this Application declares itself the recipient of the message, accepts
* responsibility for it, and must be able to respond appropriately to the sending system.
*/
public abstract boolean canProcess(Message in);
/**
* <p>Calls test(Message in), routes resulting exceptions to configured destinations, and
* returns an ack (which should not normally be used since the test app is intended
* to operate in parallel with system-to-system communication). </p>
* <p>Notification routing is performed using log4j, so you need appropriate settings in a log4j
* config file (by default, ./log4j.properties). Different types of exceptions
* are all given the same severity (ERROR) but they have different loggers, based
* on the exception class name. Specifically, the loggers will be named
* ca.uhn.hl7v2.validation.error.{exception class name}. For example:
* "ca.uhn.hl7v2.validation.error.DataTypeException". Note that this allows default
* settings for all validation errors using the logger "ca.uhn.hl7v2.validation.error".
* The intent is for different exceptions to result in different actions, e.g. a
* ProfileNotHL7CompliantException should probably just be logged or ignored, while a
* ProfileNotFollowedException should probably be emailed to an administrator. </p>
*/
public Message processMessage(Message in) throws HL7Exception {
String context = null;
try {
context = this.parser.encode(in);
} catch (HL7Exception e) {
context = "message not encodable";
}
//update logging context with message text
NDC.push(context);
LoggerFactory.getLogger("ca.uhn.hl7v2.validation.error").info("Testing message");
HL7Exception[] problems = test(in);
sendNotifications(problems);
NDC.pop();
Message ack = null;
try {
ack = ca.uhn.hl7v2.app.DefaultApplication.makeACK((Segment) in.get("MSH"));
addProblemsToACK(ack, problems);
} catch (java.io.IOException e) {
throw new HL7Exception(e);
}
return ack;
}
/**
* <p>Send notification of problems to specified destinations (e.g. log file, email).
*/
private void sendNotifications(HL7Exception[] problems) {
for (int i = 0; i < problems.length; i++) {
String exName = problems[i].getClass().getName();
String logName = "ca.uhn.hl7v2.validation.error" + exName.substring(exName.lastIndexOf('.'));
LoggerFactory.getLogger(logName).error("message validation failure", problems[i]);
}
}
private void addProblemsToACK(Message ack, HL7Exception[] problems) throws HL7Exception {
Terser t = new Terser(ack);
if (problems.length > 0) {
t.set("MSA-1", "AE");
t.set("MSA-3", "Errors were encountered while testing the message");
}
/*
Segment err = (Segment) ack.get("ERR");
for (int i = 0; i < problems.length; i++) {
// problems[i].populate(err); FIXME: broken! needs database
}
*/
}
/**
* Tests the message in some way (as defined by implementing class).
* @return exceptions that describe any identified problems with the message
* @throws HL7Exception if the message can't be tested (not for errors disovered
* during testing)
*/
public abstract HL7Exception[] test(Message in) throws HL7Exception;
}