ca.uhn.hl7v2.llp

Class MinLowerLayerProtocol

java.lang.Object

ca.uhn.hl7v2.llp.LowerLayerProtocol

ca.uhn.hl7v2.llp.MinLowerLayerProtocol

public class MinLowerLayerProtocol
extends LowerLayerProtocol

Implements the "Minimal Lower Layer Protocol" from the HL7 Implementation Guide, Appendix C. In other words, provides a reader and a writer that can be used to communicate with a server that uses the minimal LLP.

Note:

The MLLP Block is framed by single-byte values. The characters transmitted within the MLLP Block have to be encoded in such a way that the HL7 Content does not conflict with the byte values used for framing. Some multi-byte character encodings (e.g. UTF-16, UTF-32) may result in byte values equal to the MLLP framing characters or byte values lower than 0x1F, resulting in errors. These character encodings are therefore not supported by MLLP. MLLP supports all single-byte character encodings (e.g. iso-8859-x, cp1252) as well as UTF-8 and Shift_JIS. The byte values used by UTF-8 do not conflict with the byte values used for MLLP framing.

HAPI still tries to support UTF-16 and UTF-32 as best as possible. To be able to detect per-message encoding information in MSH-18 with these encodings, corresponding byte order marks (BOMs) are expected at the beginning of the message payload (i.e. AFTER the MLLP start byte) to be able to decode the message in order to read the MSH-18 field. This scheme is also followed when the MinLLPWriter sends out UTF-16 or UTF-32-encoded MLLP messages unless #setOmitBOM(boolean) is explicitly set to true.

In general, it is NOT recommended to use UTF-16 or UTF-32.

Author:

Bryan Tripp, Christian Ohr

See Also:

MinLLPReader, MinLLPWriter

Field Summary

Fields inherited from class ca.uhn.hl7v2.llp.LowerLayerProtocol

charset

Constructor Summary

Constructors

Constructor and Description
MinLowerLayerProtocol()
MinLowerLayerProtocol(boolean respectMSH18)
MinLowerLayerProtocol(boolean respectMSH18, boolean omitBOM)

Method Summary

Modifier and Type	Method and Description
HL7Reader	getReader(InputStream in) Creates an HL7Reader that implements message reading according to this protocol.
HL7Writer	getWriter(OutputStream out) Creates an HL7Writer that implements message writing according to this protocol.

Methods inherited from class ca.uhn.hl7v2.llp.LowerLayerProtocol

logCharacterReceived, makeLLP, makeLLP, setCharset, setCharset

Methods inherited from class java.lang.Object

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

Constructor Detail

MinLowerLayerProtocol

public MinLowerLayerProtocol()

MinLowerLayerProtocol

public MinLowerLayerProtocol(boolean respectMSH18)

MinLowerLayerProtocol

public MinLowerLayerProtocol(boolean respectMSH18,
                             boolean omitBOM)

Method Detail

getReader

public HL7Reader getReader(InputStream in)
                    throws LLPException

Creates an HL7Reader that implements message reading according to this protocol.

Specified by:

getReader in class LowerLayerProtocol

Throws:

LLPException

getWriter

public HL7Writer getWriter(OutputStream out)
                    throws LLPException

Creates an HL7Writer that implements message writing according to this protocol.

Specified by:

getWriter in class LowerLayerProtocol

Throws:

LLPException