MLLP

Since Camel 2.17

Both producer and consumer are supported

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>

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

The component level is the highest level which holds general and common configurations that are inherited by the endpoints. For example a component may have security settings, credentials for authentication, urls for network connection and so forth.

Some components only have a few options, and others may have many. Because components typically have pre configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.

Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.

Configuring Endpoint Options

Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.

Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL as a type safe way of configuring endpoints.

A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.

The following two sections lists all the options, firstly for the component followed by the endpoint.

Component Options

The MLLP component supports 6 options, which are listed below.

Name Description Default Type

bridgeErrorHandler (consumer)

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

boolean

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

boolean

autowiredEnabled (advanced)

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

boolean

defaultCharset (advanced)

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

Charset

logPhi (advanced)

Set the component to log PHI data.

Boolean

logPhiMaxBytes (advanced)

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

Integer

Endpoint Options

The MLLP endpoint is configured using URI syntax:

mllp:hostname:port

with the following path and query parameters:

Path Parameters (2 parameters)

Name Description Default Type

hostname (common)

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

String

port (common)

Required Port number for the TCP connection.

int

Query Parameters (25 parameters)

Name Description Default Type

autoAck (common)

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

boolean

hl7Headers (common)

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

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.

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.

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.

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.

boolean

exceptionHandler (consumer (advanced))

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option 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 (advanced))

Sets the exchange pattern when the consumer creates an exchange.

Enum values:

  • InOnly

  • InOut

  • InOptionalOut

ExchangePattern

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

boolean

charsetName (codec)

Set the CamelCharsetName property on the exchange.

String

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.

Integer

keepAlive (tcp)

Enable/disable the SO_KEEPALIVE socket option.

Boolean

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.

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.

int

receiveBufferSize (tcp)

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

Integer

reuseAddress (tcp)

Enable/disable the SO_REUSEADDR socket option.

Boolean

sendBufferSize (tcp)

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

Integer

tcpNoDelay (tcp)

Enable/disable the TCP_NODELAY socket option.

Boolean

acceptTimeout (timeout)

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

int

bindRetryInterval (timeout)

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

int

bindTimeout (timeout)

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

int

connectTimeout (timeout)

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

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

readTimeout (timeout)

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

int

receiveTimeout (timeout)

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

int

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. The MLLP Consumer can read messages without sending any HL7 Acknowledgement if the automatic acknowledgement is disabled and exchange pattern is InOnly.

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.

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 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

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. The MLLP Producer can ignore acknowledgements when configured with InOnly exchange pattern.

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

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

Spring Boot Auto-Configuration

When using mllp with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

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

The component supports 7 options, which are listed below.

Name Description Default Type

camel.component.mllp.autowired-enabled

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

Boolean

camel.component.mllp.bridge-error-handler

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

false

Boolean

camel.component.mllp.default-charset

Set the default character set to use for byte to/from String conversions. The option is a java.nio.charset.Charset type.

Charset

camel.component.mllp.enabled

Whether to enable auto configuration of the mllp component. This is enabled by default.

Boolean

camel.component.mllp.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean

camel.component.mllp.log-phi

Set the component to log PHI data.

true

Boolean

camel.component.mllp.log-phi-max-bytes

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

5120

Integer