Java tutorial
package org.wso2.carbon.inbound.endpoint.protocol.hl7.core; /** * Copyright (c) 2015, WSO2 Inc. (http://www.wso2.org) All Rights Reserved. * * WSO2 Inc. licenses this file to you under the Apache License, * Version 2.0 (the "License"); you may not use this file except * in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ import ca.uhn.hl7v2.HL7Exception; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http.nio.reactor.IOEventDispatch; import org.apache.http.nio.reactor.IOSession; import org.apache.synapse.transport.passthru.util.BufferFactory; import org.apache.synapse.transport.passthru.util.ControlledByteBuffer; import org.wso2.carbon.inbound.endpoint.protocol.hl7.codec.HL7Codec; import org.wso2.carbon.inbound.endpoint.protocol.hl7.context.MLLPContext; import org.wso2.carbon.inbound.endpoint.protocol.hl7.context.MLLPContextFactory; import org.wso2.carbon.inbound.endpoint.protocol.hl7.util.HL7MessageUtils; import java.io.IOException; import java.nio.ByteBuffer; import java.nio.channels.ReadableByteChannel; public class MLLPSourceHandler implements IOEventDispatch { private static final Log log = LogFactory.getLog(MLLPSourceHandler.class); private volatile HL7Processor hl7Processor; private final ByteBuffer hl7TrailerBuf = ByteBuffer.wrap(MLLPConstants.HL7_TRAILER); private BufferFactory bufferFactory; private ControlledByteBuffer inputBuffer; private ControlledByteBuffer outputBuffer; public MLLPSourceHandler() { /* default constructor */ } public MLLPSourceHandler(HL7Processor hl7Processor) { super(); this.hl7Processor = hl7Processor; this.bufferFactory = (BufferFactory) hl7Processor.getInboundParameterMap() .get(MLLPConstants.INBOUND_HL7_BUFFER_FACTORY); } @Override public void connected(IOSession session) { if (session.getAttribute(MLLPConstants.MLLP_CONTEXT) == null) { session.setAttribute(MLLPConstants.MLLP_CONTEXT, MLLPContextFactory.createMLLPContext(session, hl7Processor)); } inputBuffer = bufferFactory.getBuffer(); outputBuffer = bufferFactory.getBuffer(); } @Override public void inputReady(IOSession session) { ReadableByteChannel ch = (ReadableByteChannel) session.channel(); MLLPContext mllpContext = (MLLPContext) session.getAttribute(MLLPConstants.MLLP_CONTEXT); inputBuffer.clear(); try { int read; while ((read = ch.read(inputBuffer.getByteBuffer())) > 0) { inputBuffer.flip(); try { mllpContext.getCodec().decode(inputBuffer.getByteBuffer(), mllpContext); } catch (MLLProtocolException e) { handleException(session, mllpContext, e); clearInputBuffers(mllpContext); return; } catch (HL7Exception e) { handleException(session, mllpContext, e); if (mllpContext.isAutoAck()) { mllpContext.setNackMode(true); mllpContext.setHl7Message(HL7MessageUtils.createDefaultNack(e.getMessage())); mllpContext.requestOutput(); } else { hl7Processor.processError(mllpContext, e); } return; } catch (IOException e) { shutdownConnection(session, mllpContext, e); return; } } if (mllpContext.getCodec().isReadComplete()) { if (mllpContext.isAutoAck()) { mllpContext.requestOutput(); bufferFactory.release(inputBuffer); inputBuffer = bufferFactory.getBuffer(); } try { hl7Processor.processRequest(mllpContext); } catch (Exception e) { shutdownConnection(session, mllpContext, e); } } if (read < 0) { clearInputBuffers(mllpContext); session.close(); } } catch (IOException e) { shutdownConnection(session, mllpContext, e); } } private void clearInputBuffers(MLLPContext context) { bufferFactory.release(inputBuffer); inputBuffer = bufferFactory.getBuffer(); context.reset(); } @Override public void outputReady(IOSession session) { MLLPContext mllpContext = (MLLPContext) session.getAttribute(MLLPConstants.MLLP_CONTEXT); writeOut(session, mllpContext); } private void writeOut(IOSession session, MLLPContext mllpContext) { outputBuffer.clear(); try { mllpContext.getCodec().encode(outputBuffer.getByteBuffer(), mllpContext); } catch (HL7Exception e) { shutdownConnection(session, mllpContext, e); } catch (IOException e) { shutdownConnection(session, mllpContext, e); } if (outputBuffer == null) { handleException(session, mllpContext, new MLLProtocolException("HL7 Codec is in an inconsistent state: " + mllpContext.getCodec().getState() + ". Shutting down connection.")); return; } try { session.channel().write(outputBuffer.getByteBuffer()); if (mllpContext.getCodec().isWriteTrailer()) { session.channel().write(hl7TrailerBuf); hl7TrailerBuf.flip(); mllpContext.getCodec().setState(HL7Codec.WRITE_COMPLETE); } // bufferFactory.release(outputBuffer); } catch (IOException e) { shutdownConnection(session, mllpContext, e); } if (mllpContext.getCodec().isWriteComplete()) { if (mllpContext.isMarkForClose()) { shutdownConnection(session, mllpContext, null); } else { bufferFactory.release(outputBuffer); outputBuffer = bufferFactory.getBuffer(); mllpContext.setMessageId("RESPONDED"); mllpContext.reset(); mllpContext.requestInput(); } } } @Override public void timeout(IOSession session) { MLLPContext mllpContext = (MLLPContext) session.getAttribute(MLLPConstants.MLLP_CONTEXT); shutdownConnection(session, mllpContext, null); } @Override public void disconnected(IOSession session) { MLLPContext mllpContext = (MLLPContext) session.getAttribute(MLLPConstants.MLLP_CONTEXT); shutdownConnection(session, mllpContext, null); } private void shutdownConnection(IOSession session, MLLPContext mllpContext, Exception e) { if (e != null) { log.error("An unexpected error has occurred."); handleException(session, mllpContext, e); } bufferFactory.release(inputBuffer); bufferFactory.release(outputBuffer); session.close(); } private void handleException(IOSession session, MLLPContext mllpContext, Exception e) { log.error("Exception caught in I/O handler.", e); } }