Chapter 215. MLLP Component

Available as of Camel version 2.17

The MLLP component is specifically designed to handle the nuances of the MLLP protocol and provide the functionality required by Healthcare providers to communicate with other systems using the MLLP protocol.  The MLLP component  provides a simple configuration URI, automated HL7 acknowledgment generation and automatic acknowledgement interrogation.

The MLLP protocol does not typically use a large number of concurrent TCP connections - a single active TCP connection is the normal case.  Therefore, the MLLP component uses a simple thread-per-connection model based an standard Java Sockets. This keeps the implementation simple and eliminates the dependencies other than Camel itself.

The component supports the following:

  • A Camel consumer using a TCP Server
  • A Camel producer using a TCP Client

The MLLP component uses byte[] payloads, and relies on Camel Type Conversion to convert byte[] to other types.  

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-mllp</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

215.1. MLLP Options

The MLLP component supports 5 options which are listed below.

NameDescriptionDefaultType

logPhi (advanced)

Set the component to log PHI data.

true

Boolean

logPhiMaxBytes (advanced)

Set the maximum number of bytes of PHI that will be logged in a log entry.

5120

Integer

defaultCharset (advanced)

Set the default character set to use for byte to/from String conversions.

ISO-8859-1

String

configuration (common)

Sets the default configuration to use when creating MLLP endpoints.

 

MllpConfiguration

resolveProperty Placeholders (advanced)

Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders.

true

boolean

The MLLP endpoint is configured using URI syntax:

mllp:hostname:port

with the following path and query parameters:

215.1.1. Path Parameters (2 parameters):

NameDescriptionDefaultType

hostname

Required Hostname or IP for connection for the TCP connection. The default value is null, which means any local IP address

 

String

port

Required Port number for the TCP connection

 

int

215.1.2. Query Parameters (27 parameters):

NameDescriptionDefaultType

autoAck (common)

Enable/Disable the automatic generation of a MLLP Acknowledgement MLLP Consumers only

true

boolean

bufferWrites (common)

Deprecated Enable/Disable the buffering of HL7 payloads before writing to the socket.

false

boolean

hl7Headers (common)

Enable/Disable the automatic generation of message headers from the HL7 Message MLLP Consumers only

true

boolean

requireEndOfData (common)

Enable/Disable strict compliance to the MLLP standard. The MLLP standard specifies START_OF_BLOCKhl7 payloadEND_OF_BLOCKEND_OF_DATA, however, some systems do not send the final END_OF_DATA byte. This setting controls whether or not the final END_OF_DATA byte is required or optional.

true

boolean

stringPayload (common)

Enable/Disable converting the payload to a String. If enabled, HL7 Payloads received from external systems will be validated converted to a String. If the charsetName property is set, that character set will be used for the conversion. If the charsetName property is not set, the value of MSH-18 will be used to determine th appropriate character set. If MSH-18 is not set, then the default ISO-8859-1 character set will be use.

true

boolean

validatePayload (common)

Enable/Disable the validation of HL7 Payloads If enabled, HL7 Payloads received from external systems will be validated (see Hl7Util.generateInvalidPayloadExceptionMessage for details on the validation). If and invalid payload is detected, a MllpInvalidMessageException (for consumers) or a MllpInvalidAcknowledgementException will be thrown.

false

boolean

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to receive incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. If disabled, the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions by logging them at WARN or ERROR level and ignored.

true

boolean

exceptionHandler (consumer)

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this options is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

 

ExceptionHandler

exchangePattern (consumer)

Sets the exchange pattern when the consumer creates an exchange.

InOut

ExchangePattern

synchronous (advanced)

Sets whether synchronous processing should be strictly used (this component only supports synchronous operations).

true

boolean

backlog (tcp)

The maximum queue length for incoming connection indications (a request to connect) is set to the backlog parameter. If a connection indication arrives when the queue is full, the connection is refused.

5

Integer

lenientBind (tcp)

TCP Server Only - Allow the endpoint to start before the TCP ServerSocket is bound. In some environments, it may be desirable to allow the endpoint to start before the TCP ServerSocket is bound.

false

boolean

maxConcurrentConsumers (tcp)

The maximum number of concurrent MLLP Consumer connections that will be allowed. If a new connection is received and the maximum is number are already established, the new connection will be reset immediately.

5

int

reuseAddress (tcp)

Enable/disable the SO_REUSEADDR socket option.

false

Boolean

acceptTimeout (timeout)

Timeout (in milliseconds) while waiting for a TCP connection TCP Server Only

60000

int

bindRetryInterval (timeout)

TCP Server Only - The number of milliseconds to wait between bind attempts

5000

int

bindTimeout (timeout)

TCP Server Only - The number of milliseconds to retry binding to a server port

30000

int

connectTimeout (timeout)

Timeout (in milliseconds) for establishing for a TCP connection TCP Client only

30000

int

idleTimeout (timeout)

The approximate idle time allowed before the Client TCP Connection will be reset. A null value or a value less than or equal to zero will disable the idle timeout.

 

Integer

maxReceiveTimeouts (timeout)

Deprecated The maximum number of timeouts (specified by receiveTimeout) allowed before the TCP Connection will be reset.

 

Integer

keepAlive (tcp)

Enable/disable the SO_KEEPALIVE socket option.

true

Boolean

receiveBufferSize (tcp)

Sets the SO_RCVBUF option to the specified value (in bytes)

8192

Integer

sendBufferSize (tcp)

Sets the SO_SNDBUF option to the specified value (in bytes)

8192

Integer

tcpNoDelay (tcp)

Enable/disable the TCP_NODELAY socket option.

true

Boolean

readTimeout (timeout)

The SO_TIMEOUT value (in milliseconds) used after the start of an MLLP frame has been received

5000

int

receiveTimeout (timeout)

The SO_TIMEOUT value (in milliseconds) used when waiting for the start of an MLLP frame

15000

int

charsetName (codec)

Set the CamelCharsetName property on the exchange

 

String

215.2. MLLP Consumer

The MLLP Consumer supports receiving MLLP-framed messages and sending HL7 Acknowledgements.  The MLLP Consumer can automatically generate the HL7 Acknowledgement (HL7 Application Acknowledgements only - AA, AE and AR), or the acknowledgement can be specified using the CamelMllpAcknowledgement exchange property.  Additionally, the type of acknowledgement that will be generated can be controlled by setting the CamelMllpAcknowledgementType exchange property.

215.3. Message Headers

The MLLP Consumer adds these headers on the Camel message:

Key

Description

 

CamelMllpLocalAddress

 The local TCP Address of the Socket

 

CamelMllpRemoteAddress

 The local TCP Address of the Socket 

 

CamelMllpSendingApplication

MSH-3 value

 

CamelMllpSendingFacility

MSH-4 value

 

CamelMllpReceivingApplication

MSH-5 value

 

CamelMllpReceivingFacility

MSH-6 value

 

CamelMllpTimestamp

MSH-7 value

 

CamelMllpSecurity

MSH-8 value 

 

CamelMllpMessageType

MSH-9 value 

 

CamelMllpEventType

MSH-9-1 value 

 

CamelMllpTriggerEvent

MSH-9-2 value 

 

CamelMllpMessageControlId

MSH-10 value 

 

CamelMllpProcessingId

MSH-11 value 

 

CamelMllpVersionId

MSH-12 value 

 

CamelMllpCharset

MSH-18 value 

 

All headers are String types. If a header value is missing, its value is null.

215.4. Exchange Properties

The type of acknowledgment the MLLP Consumer generates and state of the TCP Socket can be controlled by these properties on the Camel exchange:

Key

Type

Description

CamelMllpAcknowledgement

byte[] 

If present, this property will we sent to client as the MLLP Acknowledgement

CamelMllpAcknowledgementString

 String

If present and CamelMllpAcknowledgement is not present, this property will we sent to client as the MLLP Acknowledgement

CamelMllpAcknowledgementMsaText

String

If neither CamelMllpAcknowledgement or CamelMllpAcknowledgementString are present and autoAck is true, this property can be used to specify the the contents of MSA-3 in the generated HL7 acknowledgement

CamelMllpAcknowledgementType

 String

If neither CamelMllpAcknowledgement or CamelMllpAcknowledgementString are present and autoAck is true, this property can be used to specify the HL7 acknowledgement type (i.e. AA, AE, AR)

CamelMllpAutoAcknowledge

Boolean

Overrides the autoAck query parameter

CamelMllpCloseConnectionBeforeSend

Boolean

If true, the Socket will be closed before sending data

CamelMllpResetConnectionBeforeSend

Boolean

If true, the Socket will be reset before sending data

CamelMllpCloseConnectionAfterSend

Boolean

If true, the Socket will be closed immediately after sending data

CamelMllpResetConnectionAfterSend

Boolean

If true, the Socket will be reset immediately after sending any data

215.5. MLLP Producer

The MLLP Producer supports sending MLLP-framed messages and receiving HL7 Acknowledgements.  The MLLP Producer interrogates the HL7 Acknowledgments and raises exceptions if a negative acknowledgement is received.  The received acknowledgement is interrogated and an exception is raised in the event of a negative acknowledgement.

215.6. Message Headers

The MLLP Producer adds these headers on the Camel message:

Key

Description

 

CamelMllpLocalAddress

 The local TCP Address of the Socket

 

CamelMllpRemoteAddress

 The remote TCP Address of the Socket

 

CamelMllpAcknowledgement

 The HL7 Acknowledgment byte[] received

 

CamelMllpAcknowledgementString

 The HL7 Acknowledgment received, converted to a String

 

215.7. Exchange Properties

The state of the TCP Socket can be controlled by these properties on the Camel exchange:

Key

Type

Description

CamelMllpCloseConnectionBeforeSend

Boolean

If true, the Socket will be closed before sending data

CamelMllpResetConnectionBeforeSend

Boolean

If true, the Socket will be reset before sending data

CamelMllpCloseConnectionAfterSend

Boolean

If true, the Socket will be closed immediately after sending data

CamelMllpResetConnectionAfterSend

Boolean

If true, the Socket will be reset immediately after sending any data