Package com.framed.interop.hl7.mllp

Class MllpCodec

java.lang.Object

com.framed.interop.hl7.mllp.MllpCodec

public final class MllpCodec
extends Object

Minimal Lower Layer Protocol (MLLP) framing.

An HL7 message is wrapped as <VT> message <FS><CR>, i.e. a start-block byte (0x0B), the message bytes, an end-block byte (0x1C) and a carriage return (0x0D). This is the de-facto transport framing for HL7 v2 over TCP.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	CARRIAGE_RETURN	Trailing carriage return (0x0D).
static final int	END_BLOCK	End-of-block marker (file separator, 0x1C).
static final int	START_BLOCK	Start-of-block marker (vertical tab, 0x0B).

Method Summary

Modifier and Type	Method	Description
static byte[]	frame(String message)	Frames an HL7 message for MLLP transport.
static String	readMessage(InputStream in)	Reads a single MLLP-framed message from a stream, blocking until a full frame arrives.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

START_BLOCK

public static final int START_BLOCK

Start-of-block marker (vertical tab, 0x0B).

See Also:

• Constant Field Values

END_BLOCK

public static final int END_BLOCK

End-of-block marker (file separator, 0x1C).

See Also:

• Constant Field Values

CARRIAGE_RETURN

public static final int CARRIAGE_RETURN

Trailing carriage return (0x0D).

See Also:

• Constant Field Values

Method Details

frame

public static byte[] frame(String message)

Frames an HL7 message for MLLP transport.

Parameters:

message - the HL7 message text

Returns:

the MLLP-framed bytes

readMessage

public static String readMessage(InputStream in)
                          throws IOException

Reads a single MLLP-framed message from a stream, blocking until a full frame arrives.

Leading bytes before START_BLOCK are skipped. The terminating END_BLOCK (and the trailing CARRIAGE_RETURN, if present) are consumed but not returned. Tolerant of fragmented reads, since the stream is consumed one byte at a time until the frame completes.

Parameters:

in - the input stream

Returns:

the message text, or null on clean EOF / truncated frame (connection closed)

Throws:

IOException - if the underlying stream fails