HAPI v2 after terser: get entire changed message - hapi

Question

I have an HL7 message whose content I'm manipulating slightly with the terser.set() method. Once I've done that, I see in the debugger that it's been changed just how I want it, but I can't seem to get the whole message back intact. I've tried (for example):
HapiContext context = new DefaultHapiContext();
Parser parser = context.getGenericParser();
Message message = parser.parse( MESSAGE );
Terser terser = new Terser( message );
terser.set( "/PID-2", "XXX XX XXXX" );
String fixedMessage = message.encode();
...which gets me close, however, lines (segment lines) that ended in just vertical bars (pipes) with no values in their fields come back trimmed (the vertical bars are simply dropped). I want the message to remain identical to what I put in (if also modified where I did it on purpose).

Answer 1

I think you need to use addForcedEncode in the ParserConfiguration.
Like
#Test
public void testSetManualRepetitions() {
try {
String m = "MSH|^~\\&|hl7Integration|hl7Integration|||||ADT^A01|||2.3|\r" +
"EVN|A01|20130617154644\r" +
"PID|1|465 306 5961||407623|Wood^Patrick^^^MR||19700101|1||||||||||\r" +
"PV1|1||Location||||||||||||||||261938_6_201306171546|||||||||||||||||||||||||20130617134644|||||||||";
HapiContext hc = new DefaultHapiContext();
ExecutorService es = hc.getExecutorService(); // to avoid npe when closing context should be fixed https://sourceforge.net/p/hl7api/bugs/223/
ParserConfiguration pc = hc.getParserConfiguration();
PipeParser pipeParser = hc.getPipeParser();
Message message = pipeParser.parse(m);
Terser terser = new Terser(message);
//Add first Address
terser.set("/.PID-11(0)-1", "13 Oxford Road");
terser.set("/.PID-11(0)-3", "Oxford");
//Add second Address
terser.set("/.PID-11(1)-1", "16 London Road");
terser.set("/.PID-11(1)-3", "London");
pc.addForcedEncode("PID-26-1"); // make sure PID has 26 fields
System.out.println(message.encode().replaceAll("\r", "\r\n"));
hc.close();
} catch (HL7Exception e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
yields:
/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/bin/java -ea -Didea.launcher.port=7540 "-Didea.launcher.bin.path=/Applications/IntelliJ IDEA CE.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath "/Applications/IntelliJ IDEA CE.app/Contents/lib/idea_rt.jar:/Applications/IntelliJ IDEA CE.app/Contents/plugins/junit/lib/junit-rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/lib/tools.jar:/Users/thomas/git/Hapi-HL7-Terser/target/test-classes:/Users/thomas/.m2/repository/junit/junit/4.4/junit-4.4.jar:/Users/thomas/.m2/repository/ca/uhn/hapi/hapi-base/2.2/hapi-base-2.2.jar:/Users/thomas/.m2/repository/ca/uhn/hapi/hapi-structures-v21/2.2/hapi-structures-v21-2.2.jar:/Users/thomas/.m2/repository/ca/uhn/hapi/hapi-structures-v23/2.2/hapi-structures-v23-2.2.jar:/Users/thomas/.m2/repository/ca/uhn/hapi/hapi-structures-v24/2.2/hapi-structures-v24-2.2.jar:/Users/thomas/.m2/repository/ca/uhn/hapi/hapi-structures-v25/2.2/hapi-structures-v25-2.2.jar:/Users/thomas/.m2/repository/org/slf4j/slf4j-simple/1.6.0/slf4j-simple-1.6.0.jar:/Users/thomas/.m2/repository/org/slf4j/slf4j-api/1.6.0/slf4j-api-1.6.0.jar:/Users/thomas/.m2/repository/org/slf4j/log4j-over-slf4j/1.6.2/log4j-over-slf4j-1.6.2.jar" com.intellij.rt.execution.application.AppMain com.intellij.rt.execution.junit.JUnitStarter -ideVersion5 com.hl7integration.hapi.tests.SetRepetitionsTerserTest,testSetManualRepetitions
68 [main] INFO ca.uhn.hl7v2.util.Home - hapi.home is set to /Users/thomas/git/Hapi-HL7-Terser/.
170 [main] INFO ca.uhn.hl7v2.VersionLogger - HAPI version is: 2.2
197 [main] INFO ca.uhn.hl7v2.VersionLogger - Default Structure libraries found for HL7 versions 2.1, 2.3, 2.4, 2.5,
MSH|^~\&|hl7Integration|hl7Integration|||||ADT^A01|||2.3
EVN|A01|20130617154644
PID|1|465 306 5961||407623|Wood^Patrick^^^MR||19700101|1|||13 Oxford Road^^Oxford~16 London Road^^London|||||||||||||||
PV1|1||Location||||||||||||||||261938_6_201306171546|||||||||||||||||||||||||20130617134644
Technically you are not changing the message, you parse it to a Java object and encode it back to string. So that your output message looks like your input message. There could still be subtle differences afterwards (e.g. if your input message is dynamic).
From the docs (http://hl7api.sourceforge.net/configuring_hapi.html):
Forced Encoding
By default, when encoding a message HAPI will not encode any segments or fields that have no content and therefore have no semantic meaning in the message.
This can cause problems if you need to transmit a message to a system that expects certain empty content to be present in order to get "hints" about where in the message it is.
The addForcedEncode method may be used to add Terser paths which should be forced to be encoded:
parser.getParserConfiguration().addForcedEncode("PATIENT_RESULT/ORDER_OBSERVATION/ORC-4");
// ORC-4 will still exist (but be empty) even if ORC has no content
String encoded = parser.encode(message);
See the JavaDoc for examples.