Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF 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. */ package org.apache.synapse.format.hessian; import org.apache.axiom.om.OMAbstractFactory; import org.apache.axiom.om.OMElement; import org.apache.axiom.om.OMFactory; import org.apache.axiom.om.OMNamespace; import org.apache.axiom.om.OMText; import org.apache.axis2.AxisFault; import org.apache.axis2.builder.Builder; import org.apache.axis2.context.MessageContext; import org.apache.axis2.description.Parameter; import org.apache.axis2.transport.base.BaseConstants; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.synapse.SynapseConstants; import org.apache.synapse.core.SynapseEnvironment; import org.apache.synapse.transport.nhttp.NhttpConstants; import org.apache.synapse.util.SynapseBinaryDataSource; import javax.activation.DataHandler; import java.io.IOException; import java.io.InputStream; import java.io.PushbackInputStream; /** * Enables a message encoded using the Hessian binary protocol to be received by axis2/synapse * and this builds the HessianDataSource to represent the hessian message inside the SOAP info-set * * @see org.apache.axis2.builder.Builder * @see org.apache.synapse.util.SynapseBinaryDataSource */ public class HessianMessageBuilder implements Builder { private static final Log log = LogFactory.getLog(HessianMessageBuilder.class); /** * Returns an OMElement from a Hessian encoded message * * @param inputStream stream containing the Hessian message to be built * @param contentType content type of the message * @param messageContext message to which the hessian message has to be attached * @return OMElement containing Hessian data handler keeping the message * @throws AxisFault in case of a failure in building the hessian message * * @see org.apache.axis2.builder.Builder#processDocument(java.io.InputStream, * String, org.apache.axis2.context.MessageContext) */ public OMElement processDocument(final InputStream inputStream, final String contentType, final MessageContext messageContext) throws AxisFault { if (log.isDebugEnabled()) { log.debug("Start building the hessian message in to a HessianDataSource"); } OMFactory factory = OMAbstractFactory.getOMFactory(); OMNamespace ns = factory.createOMNamespace(HessianConstants.HESSIAN_NAMESPACE_URI, HessianConstants.HESSIAN_NS_PREFIX); OMElement element = factory.createOMElement(HessianConstants.HESSIAN_ELEMENT_LOCAL_NAME, ns); try { Parameter synEnv = messageContext.getConfigurationContext().getAxisConfiguration() .getParameter(SynapseConstants.SYNAPSE_ENV); PushbackInputStream pis = detectAndMarkMessageFault(messageContext, inputStream); DataHandler dataHandler; if (synEnv != null && synEnv.getValue() != null) { dataHandler = new DataHandler( new SynapseBinaryDataSource(pis, contentType, (SynapseEnvironment) synEnv.getValue())); } else { // add Hessian data inside a data handler dataHandler = new DataHandler(new SynapseBinaryDataSource(pis, contentType)); } OMText textData = factory.createOMText(dataHandler, true); element.addChild(textData); // indicate that message faults shall be handled as http 200 messageContext.setProperty(NhttpConstants.FAULTS_AS_HTTP_200, NhttpConstants.TRUE); } catch (IOException e) { String msg = "Unable to create the HessianDataSource"; log.error(msg, e); throw new AxisFault(msg, e); } if (log.isDebugEnabled()) { log.debug("Building the hessian message using HessianDataSource is successful"); } return element; } /** * Reads the first four bytes of the inputstream to detect whether the message represents a * fault message. Once a fault message has been detected, a property used to mark fault messages * is stored in the Axis2 message context. The implementaton uses a PushbackInputStream to be * able to put those four bytes back at the end of processing. * * @param messageContext the Axis2 message context * @param inputStream the inputstream to read the Hessian message * * @return the wrapped (pushback) input stream * * @throws IOException if an I/O error occurs */ private PushbackInputStream detectAndMarkMessageFault(final MessageContext messageContext, final InputStream inputStream) throws IOException { int bytesToRead = 4; PushbackInputStream pis = new PushbackInputStream(inputStream, bytesToRead); byte[] headerBytes = new byte[bytesToRead]; int n = pis.read(headerBytes); // checking fourth byte for fault marker if (n == bytesToRead) { if (headerBytes[bytesToRead - 1] == HessianConstants.HESSIAN_V1_FAULT_IDENTIFIER || headerBytes[bytesToRead - 1] == HessianConstants.HESSIAN_V2_FAULT_IDENTIFIER) { messageContext.setProperty(BaseConstants.FAULT_MESSAGE, SynapseConstants.TRUE); if (log.isDebugEnabled()) { log.debug("Hessian fault detected, marking in Axis2 message context"); } } pis.unread(headerBytes); } else if (n > 0) { byte[] bytesRead = new byte[n]; System.arraycopy(headerBytes, 0, bytesRead, 0, n); pis.unread(bytesRead); } return pis; } }