package ca.uhn.hl7v2.examples.hoh;
   
   import ca.uhn.hl7v2.hoh.api.IAuthorizationServerCallback;
   import ca.uhn.hl7v2.hoh.api.IMessageHandler;
   import ca.uhn.hl7v2.hoh.api.IReceivable;
   import ca.uhn.hl7v2.hoh.api.IResponseSendable;
   import ca.uhn.hl7v2.hoh.api.MessageProcessingException;
   import ca.uhn.hl7v2.hoh.auth.SingleCredentialServerCallback;
   import ca.uhn.hl7v2.hoh.raw.api.RawSendable;
  import ca.uhn.hl7v2.hoh.raw.server.HohRawServlet;
  
  /**
   * This class illustrates an example HL7 over HTTP
   * raw message servlet for receiving and responding to messages
   */
  public class ExampleRawHl7OverHttpServlet extends HohRawServlet {
  
  	/**
  	 * Constructor
  	 */
  	public ExampleRawHl7OverHttpServlet() {
  		
  		/*
  		 * The servlet must be provided an implementation
  		 * of IMessageHandler<String>, such as the one which
  		 * is nested below
  		 */
  		setMessageHandler(new ExampleMessageHandler());
  		
  		/* 
  		 * Optionally, if we want to verify HTTP authentication,
  		 * we can specify an authorization callback
  		 */
  		IAuthorizationServerCallback callback = 
  			  new SingleCredentialServerCallback("someusername", "apassword");
  		setAuthorizationCallback(callback);
  		
  	}
  
  	/**
  	 * IMessageHandler defines the interface for the class which receives
  	 * and processes messages which come in
  	 */
  	private static class ExampleMessageHandler implements IMessageHandler<String> {
  
  		/**
  		 * This method is fired every time a message is received. The return value
  		 * contains the HL7 response value 
  		 */
  		public IResponseSendable<String> messageReceived(IReceivable<String> theReceived) 
  				   throws MessageProcessingException {
  			
  			String incomingRawMsg = theReceived.getMessage();
  			System.out.println("Received message:\n" + incomingRawMsg);
  			
  			// ... do some processing ...
  			
  			/*
  			 * Your application should generate an appropriate 
  			 * HL7 ACK message here
  			 */
  			String ack = "MSH|....."; 
  			
  			/*
  			 * If something goes horribly wrong, you can throw an 
  			 * exception and an HTTP 500 error will be generated.
  			 * However, it is preferable to return a normal HL7 ACK 
  			 * message with an "AE" response code to note an error. 
  			 */
  			boolean somethingFailed = false;
  
              // Return the raw response message
  			return new RawSendable(ack);
  		}
  		
  	}
  	
  }