Java tutorial
package org.marketcetera.client.jms; import java.io.StringWriter; import java.io.StringReader; import javax.jms.*; import javax.xml.bind.*; import org.marketcetera.client.brokers.BrokerStatus; import org.marketcetera.trade.FIXResponseImpl; import org.marketcetera.trade.ReportBaseImpl; import org.marketcetera.util.log.I18NBoundMessage1P; import org.marketcetera.util.log.SLF4JLoggerProxy; import org.marketcetera.util.misc.ClassVersion; import org.springframework.jms.support.converter.MessageConversionException; import org.springframework.jms.support.converter.MessageConverter; import org.apache.commons.lang.ObjectUtils; /* $License$ */ /** * Converts messaging objects to an XML representation that can be * sent over JMS. This class is not meant to be used by clients of * this package. * * @author anshul@marketcetera.com * @version $Id$ * @since 1.5.0 */ @ClassVersion("$Id$") public class JMSXMLMessageConverter implements MessageConverter { /** * Creates an instance. * * @throws JAXBException if there were errors initializing the * XML marshalling / unmarshalling system. */ public JMSXMLMessageConverter() throws JAXBException { mContext = JAXBContext.newInstance(OrderEnvelope.class, ReportBaseImpl.class, FIXResponseImpl.class, BrokerStatus.class); } /** * Converts a JMS Message to a messaging object. * * @param message the received JMS message. It should be of type * {@link javax.jms.ObjectMessage}. * * @return the messaging object converted from the supplied JMS message. * * @throws javax.jms.JMSException if there were errors extracting the contents * of the JMS message. * @throws org.springframework.jms.support.converter.MessageConversionException if there were errors converting * the contents of the JMS message to a messaging object. */ @Override public Object fromMessage(Message message) throws JMSException, MessageConversionException { SLF4JLoggerProxy.debug(this, "Converting from JMS {}", message); //$NON-NLS-1$ if (message instanceof TextMessage) { Object object = null; try { object = fromXML(((TextMessage) message).getText()); } catch (JAXBException e) { throw new MessageConversionException(new I18NBoundMessage1P( Messages.ERROR_CONVERTING_MESSAGE_TO_OBJECT, ObjectUtils.toString(object)).getText(), e); } if ((object instanceof ReportBaseImpl) || (object instanceof FIXResponseImpl) || (object instanceof OrderEnvelope) || (object instanceof BrokerStatus)) { return object; } else { throw new MessageConversionException( new I18NBoundMessage1P(Messages.UNEXPECTED_MESSAGE_RECEIVED, ObjectUtils.toString(object)) .getText()); } } else { throw new MessageConversionException( new I18NBoundMessage1P(Messages.UNEXPECTED_MESSAGE_RECEIVED, ObjectUtils.toString(message)) .getText()); } } /** * Converts a messaging object to a JMS Message. * * @param inObject the message to be converted. It should either be * an order or a report. * @param session the JMS Session instance. * * @return the JMS message. * * @throws javax.jms.JMSException if there were errors serializing the * messaging object. * @throws org.springframework.jms.support.converter.MessageConversionException if the supplied object was not * an acceptable messaging object. */ @Override public Message toMessage(Object inObject, Session session) throws JMSException, MessageConversionException { SLF4JLoggerProxy.debug(this, "Converting to JMS {}", inObject); //$NON-NLS-1$ if ((inObject instanceof ReportBaseImpl) || (inObject instanceof FIXResponseImpl) || (inObject instanceof OrderEnvelope) || (inObject instanceof BrokerStatus)) { try { TextMessage message = session.createTextMessage(toXML(inObject)); //Set the type property for interoperability with .NET client. message.setStringProperty(JMS_TYPE_PROPERTY, inObject.getClass().getSimpleName()); return message; } catch (JAXBException e) { throw new MessageConversionException(new I18NBoundMessage1P( Messages.ERROR_CONVERTING_OBJECT_TO_MESSAGE, ObjectUtils.toString(inObject)).getText(), e); } } else { throw new MessageConversionException( new I18NBoundMessage1P(Messages.UNEXPECTED_MESSAGE_TO_SEND, ObjectUtils.toString(inObject)) .getText()); } } /** * Marshall the supplied object to XML. * * @param inObject the object that needs to be marshalled. * * @return the XML representation. * * @throws JAXBException if there were was an error marshalling the object * to XML. */ String toXML(Object inObject) throws JAXBException { Marshaller marshaller = getMarshaller(); StringWriter writer = new StringWriter(); marshaller.marshal(inObject, writer); //no need to close or flush the writer as they do nothing. return writer.toString(); } /** * Unmarshall the supplied object from XML to an instance. * * @param inXML the object in XML. * * @return the unmarshalled object instance. * * @throws JAXBException if there were was an error unmarshalling the * object from XML. */ Object fromXML(String inXML) throws JAXBException { Unmarshaller unMarshaller = getUnMarshaller(); StringReader reader = new StringReader(inXML); return unMarshaller.unmarshal(reader); } /** * Returns the underlying JAXB context for testing. * * @return the underlying JAXB context. */ JAXBContext getContext() { return mContext; } /** * Gets cached copy of the marshaller to use for marshalling objects to XML. * * @return the marshaller to use for marshalling objects to XML. * * @throws JAXBException if there were errors getting the marshaller. */ private Marshaller getMarshaller() throws JAXBException { Marshaller m = mMarshallers.get(); if (m == null) { m = mContext.createMarshaller(); mMarshallers.set(m); } return m; } /** * Gets the cached copy of the unmarshaller to use for unmarshalling objects * from XML. * * @return the unmarshaller to use for unmarshalling objects from XML. * * @throws JAXBException if there were errors getting the unmarshaller. */ private Unmarshaller getUnMarshaller() throws JAXBException { Unmarshaller u = mUnmarshallers.get(); if (u == null) { u = mContext.createUnmarshaller(); mUnmarshallers.set(u); } return u; } private final ThreadLocal<Marshaller> mMarshallers = new ThreadLocal<Marshaller>(); private final ThreadLocal<Unmarshaller> mUnmarshallers = new ThreadLocal<Unmarshaller>(); private final JAXBContext mContext; private static final String JMS_TYPE_PROPERTY = "metc_type"; //$NON-NLS-1$ }