ca.uhn.hl7v2.protocol.Processor Maven / Gradle / Ivy
/*
* Created on 16-Apr-2004
*/
package ca.uhn.hl7v2.protocol;
import ca.uhn.hl7v2.HL7Exception;
/**
* Encapsulates both the client and server roles of the HL7-defined
* "original mode" and "enhanced mode" processing rules. See
* HL7 v2.5 chapter 2 for specifications.
*
* @author Bryan Tripp
* @version $Revision: 1.1 $ updated on $Date: 2007/02/19 02:24:38 $ by $Author: jamesagnew $
*/
public interface Processor {
/**
* Always send acknowledgement (in MSH-15 and 16)
*/
public static final String AL = "AL";
/**
* Never send acknowledgement (in MSH-15 and 16)
*/
public static final String NE = "NE";
/**
* Send acknowledgement only on error / reject (in MSH-15 and 16)
*/
public static final String ER = "ER";
/**
* Send acknowledgement only on successful receipt (in MSH-15 and 16)
*/
public static final String SU = "SU";
/**
* Original mode: Application Accept - Enhanced mode: Application acknowledgment: Accept
*/
public static final String AA = "AA";
/**
* Original mode: Application Error - Enhanced mode: Application acknowledgment: Error
*/
public static final String AE = "AE";
/**
* Original mode: Application Reject - Enhanced mode: Application acknowledgment: Reject
*/
public static final String AR = "AR";
/**
* Enhanced mode: Accept acknowledgment: Commit Accept
*/
public static final String CA = "CA";
/**
* Enhanced mode: Accept acknow ledgment: Commit Error
*/
public static final String CE = "CE";
/**
* Enhanced mode: Accept acknowledgment: Commit Reject
*/
public static final String CR = "CR";
/**
* Sends a message to a remote system via an underlying
* TransportLayer.
*
* If the message specifies that an accept ACK is required (under enhanced mode
* processing rules) then this method may retry if transmission does not appear
* to be successful. The call to this method blocks while this is happening.
* Retries are attempted if a CR message is received, or if no message is received
* in the specified time frame. If a CE is received, an exception is thrown. If
* a CA is received, the call returns quietly.
*
* If no accept ack is required, this method returns immediately after attempting to
* send a message, throwing an exception only if there is an immediate problem (eg the
* server can't be contacted).
*
* If an accept ack is required only on error, the method waits for maxRetries *
* retryItervalMillis for an error to be returned, and assumes that there is no error
* if none appears in that time. The message is not actually resent while waiting for an
* error ACK.
*
* @param theMessage the message to send
* @param maxRetries note that this should be a small value if you demand an accept ack only
* on error
* @param retryIntervalMillis note that this should be a small value if you demand an accept ack only
* on error
* @throws TransportException if there is an immediate problem trying to send the
* message.
*/
public void send(Transportable theMessage, int maxRetries, long retryIntervalMillis) throws HL7Exception;
/**
* Indicates that the calling thread expects a message with a certain ack
* ID. If this message arrives within the specified period of time, it will
* be held in an inbound list instead of being passed on to an
* Application. If a message is in this list it isAvailable()
* and can be had via receive()
*
* @param theAckId the acknowledgement ID of the message
* @param thePeriodMillis time span during which the message should be kept if received
*/
public void reserve(String theAckId, long thePeriodMillis);
/**
* Performs a single iteration of the receiving-side
* of the HL7 original mode or enhanced mode processing rules
* (see HL7 Standard v2.5 Chapter 2; the choice of rules
* is determined by message values). Steps in the process are
* as follows:
*
* 1. TransportLayer.receive() is called to get the next message
* 2. Validation is performed and the message is stored locally.
* 2. If the message requires an accept ACK, then an accept, reject,
* or error message is returned as appropriate
* 3. If the message is an accept ack, it is added to a local list that
* can be accessed by the send() method
* 4. If the message has been reserved, it is added to the available message
* list.
* 5. Otherwise it is sent to an Application.
*
* @param expectingAck is passed to TransportLayer.receive(), and may determine
* where the message is read from (eg different sockets may be used for
* commit-level ACKs). Note that this call blocks until a message is ready
* at the specified location, so to run the Processor continuously,
* separate threads are needed to call cycle() with true and false args.
*/
public void cycle(boolean expectingAck) throws HL7Exception;
/**
* @param theAckId the acknowledgement ID of an expected message
* @return true if the message has come in and has been saved in the
* inbound message list
*/
public boolean isAvailable(String theAckId);
/**
* Gets the message with the given acknowledgement ID from
* the incoming message list. This method blocks until the
* message appears on the list. If you don't want to block,
* call isAvailable() to see if it is there.
*
* Note also that the message has no way of arriving on the list
* during this call unless the Processor is running
* as a thread, or unless some other thread is calling cycle().
*
* @param theAckId
* @param theTimeoutMillis milliseconds until the call times out
* and returns null if the desired message is not available.
* @return the incoming message with the given ack ID, or null
* if the call times out.
*/
public Transportable receive(String theAckId, long theTimeoutMillis) throws HL7Exception;
/**
* @return the operational context of this protocol instance
*/
public ProcessorContext getContext();
}