Axis 2 example source code file (BlockImpl.java)

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Java - Axis 2 tags/keywords

block, blockfactory, blockimpl, blockimplerr1, io, object, object, qname, qname, staxombuilder, webserviceexception, webserviceexception, xml, xmlstreamexception, xmlstreamexception, xmlstreamreader

The Axis 2 BlockImpl.java source code

/*
 * 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.axis2.jaxws.message.impl;

import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMOutputFormat;
import org.apache.axiom.om.impl.MTOMXMLStreamWriter;
import org.apache.axiom.om.impl.builder.StAXOMBuilder;
import org.apache.axiom.om.util.StAXUtils;
import org.apache.axis2.jaxws.ExceptionFactory;
import org.apache.axis2.jaxws.i18n.Messages;
import org.apache.axis2.jaxws.message.Block;
import org.apache.axis2.jaxws.message.Message;
import org.apache.axis2.jaxws.message.factory.BlockFactory;
import org.apache.axis2.jaxws.message.util.Reader2Writer;
import org.apache.axis2.jaxws.spi.Constants;
import org.apache.axis2.jaxws.utility.JavaUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.xml.namespace.QName;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import javax.xml.ws.WebServiceException;
import java.io.OutputStream;
import java.io.StringReader;
import java.io.Writer;

/**
 * BlockImpl Abstract Base class for various Block Implementations.
 * <p/>
 * The base class takes care of controlling the transformations between BusinessObject,
 * XMLStreamReader and SOAPElement A derived class must minimally define the following:
 * _getBOFromReader _getReaderFromBO _outputFromBO
 * <p/>
 * In addtion, the derived class may want to override the following: _getBOFromBO ...if the
 * BusinessObject is consumed when read (i.e. it is an InputSource)
 * <p/>
 * The derived classes don't have direct access to the instance data. This ensures that BlockImpl
 * controls the transformations.
 */
public abstract class BlockImpl implements Block {

    private static Log log = LogFactory.getLog(BlockImpl.class);

    protected Object busObject;
    protected Object busContext;

    protected OMElement omElement = null;

    protected QName qName;
    protected BlockFactory factory;
    protected boolean consumed = false;
    protected Message parent;

    /**
     * A Block has the following components
     *
     * @param busObject
     * @param busContext or null
     * @param qName      or null if unknown
     * @param factory    that creates the Block
     */
    protected BlockImpl(Object busObject, Object busContext, QName qName, BlockFactory factory) {
        this.busObject = busObject;
        this.busContext = busContext;
        this.qName = qName;
        this.factory = factory;
    }

    /**
     * A Block has the following components
     *
     * @param reader
     * @param busContext or null
     * @param qName      or null if unknown
     * @param factory    that creates the Block
     */
    protected BlockImpl(OMElement omElement, Object busContext, QName qName, BlockFactory factory) {
        this.omElement = omElement;
        this.busContext = busContext;
        this.qName = qName;
        this.factory = factory;
    }

    /* (non-Javadoc)
      * @see org.apache.axis2.jaxws.message.Block#getBlockFactory()
      */
    public BlockFactory getBlockFactory() {
        return factory;
    }

    /* (non-Javadoc)
      * @see org.apache.axis2.jaxws.message.Block#getBusinessContext()
      */
    public Object getBusinessContext() {
        return busContext;
    }

    public Message getParent() {
        return parent;
    }

    public void setParent(Message p) {
        parent = p;
    }

    /* (non-Javadoc)
      * @see org.apache.axis2.jaxws.message.Block#getBusinessObject(boolean)
      */
    public Object getBusinessObject(boolean consume)
            throws XMLStreamException, WebServiceException {
        if (consumed) {
            throw ExceptionFactory.makeWebServiceException(
                    Messages.getMessage("BlockImplErr1", this.getClass().getName()));
        }
        if (busObject != null) {
            busObject = _getBOFromBO(busObject, busContext, consume);
        } else {
            // Transform reader into business object
            XMLStreamReader reader;
            if (omElement.getBuilder() != null && !omElement.getBuilder().isCompleted()) {
                reader = omElement.getXMLStreamReaderWithoutCaching();
            } else {
                reader = omElement.getXMLStreamReader();
            }
            busObject = _getBOFromReader(reader, busContext);
            omElement = null;
        }

        // Save the businessObject in a local variable
        // so that we can reset the Block if consume was indicated
        Object newBusObject = busObject;
        setConsumed(consume);
        return newBusObject;
    }

    /* (non-Javadoc)
      * @see org.apache.axis2.jaxws.message.Block#getQName()
      */
    public QName getQName() throws WebServiceException {
        // If the QName is not known, find it
        try {
            if (qName == null) {
                if (omElement == null) {
                    XMLStreamReader newReader = _getReaderFromBO(busObject, busContext);
                    busObject = null;
                    StAXOMBuilder builder = new StAXOMBuilder(newReader);
                    omElement = builder.getDocumentElement();
                }
                qName = omElement.getQName();
            }
            return qName;
        } catch (Exception xse) {
            setConsumed(true);
            throw ExceptionFactory.makeWebServiceException(xse);
        }
    }

    /**
     * This method is intended for derived objects to set the qName
     *
     * @param qName
     */
    protected void setQName(QName qName) {
        this.qName = qName;
    }

    /* (non-Javadoc)
      * @see org.apache.axis2.jaxws.message.Block#getXMLStreamReader(boolean)
      */
    public XMLStreamReader getXMLStreamReader(boolean consume)
            throws XMLStreamException, WebServiceException {
        XMLStreamReader newReader = null;
        if (consumed) {
            // In some scenarios, the message is written out after the service instance is invoked.
            // In these situations, it is preferable to simply ignore this block.
            if (this.getParent() != null && getParent().isPostPivot()) {
                return _postPivot_getXMLStreamReader();
            }
            throw ExceptionFactory.makeWebServiceException(
                    Messages.getMessage("BlockImplErr1", this.getClass().getName()));
        }
        if (omElement != null) {
            if (consume) {
                if (omElement.getBuilder() != null && !omElement.getBuilder().isCompleted()) {
                    newReader = omElement.getXMLStreamReaderWithoutCaching();
                } else {
                    newReader = omElement.getXMLStreamReader();
                }
                omElement = null;
            } else {
                newReader = omElement.getXMLStreamReader();
            }
        } else if (busObject != null) {
            // Getting the reader does not destroy the BusinessObject
            busObject = _getBOFromBO(busObject, busContext, consume);
            newReader = _getReaderFromBO(busObject, busContext);
        }
        setConsumed(consume);
        return newReader;
    }

    /* (non-Javadoc)
      * @see org.apache.axiom.om.OMDataSource#getReader()
      */
    public XMLStreamReader getReader() throws XMLStreamException {
        return getXMLStreamReader(true);
    }

    /* (non-Javadoc)
      * @see org.apache.axiom.om.OMDataSource#serialize(java.io.OutputStream, org.apache.axiom.om.OMOutputFormat)
      */
    public void serialize(OutputStream output, OMOutputFormat format) throws XMLStreamException {
        MTOMXMLStreamWriter writer = new MTOMXMLStreamWriter(output, format);
        serialize(writer);
        writer.flush();
    }

    /* (non-Javadoc)
      * @see org.apache.axiom.om.OMDataSource#serialize(java.io.Writer, org.apache.axiom.om.OMOutputFormat)
      */
    public void serialize(Writer writerTarget, OMOutputFormat format) throws XMLStreamException {
        MTOMXMLStreamWriter writer =
                new MTOMXMLStreamWriter(StAXUtils.createXMLStreamWriter(writerTarget));
        writer.setOutputFormat(format);
        serialize(writer);
        writer.flush();
    }

    /* (non-Javadoc)
      * @see org.apache.axiom.om.OMDataSource#serialize(javax.xml.stream.XMLStreamWriter)
      */
    public void serialize(XMLStreamWriter writer) throws XMLStreamException {
        outputTo(writer, true);
    }

    public OMElement getOMElement() throws XMLStreamException, WebServiceException {
        OMElement newOMElement = null;
        boolean consume = true;  // get the OM consumes the message
        if (consumed) {
            throw ExceptionFactory.makeWebServiceException(
                    Messages.getMessage("BlockImplErr1", this.getClass().getName()));
        }
        if (omElement != null) {
            newOMElement = omElement;
        } else if (busObject != null) {
            // Getting the reader does not destroy the BusinessObject
            busObject = _getBOFromBO(busObject, busContext, consume);
            XMLStreamReader newReader = _getReaderFromBO(busObject, busContext);
            StAXOMBuilder builder = new StAXOMBuilder(newReader);
            newOMElement = builder.getDocumentElement();
        }
        setConsumed(consume);
        return newOMElement;
    }

    /* (non-Javadoc)
      * @see org.apache.axis2.jaxws.message.Block#isConsumed()
      */
    public boolean isConsumed() {
        return consumed;
    }

    /**
     * Once consumed, all instance data objects are nullified to prevent subsequent access
     *
     * @param consume
     * @return
     */
    public void setConsumed(boolean consume) {
        if (consume) {
            this.consumed = true;
            busObject = null;
            busContext = null;
            omElement = null;
            if (log.isDebugEnabled()) {
                // The following stack trace consumes indicates where the message is consumed
                log.debug("Message Block Monitor: Action=Consumed");
                log.debug(JavaUtils.stackToString());
            }
        } else {
            consumed = false;
        }
    }

    public boolean isQNameAvailable() {
        return (qName != null);
    }

    public void outputTo(XMLStreamWriter writer, boolean consume)
            throws XMLStreamException, WebServiceException {
        if (consumed) {
            // In some scenarios, the message is written out after the service instance is invoked.
            // In these situations, it is preferable to simply ignore this block.
            if (this.getParent() != null && getParent().isPostPivot()) {
                _postPivot_outputTo(writer);
            }
            throw ExceptionFactory.makeWebServiceException(
                    Messages.getMessage("BlockImplErr1", this.getClass().getName()));
        }
        if (omElement != null) {
            if (consume) {
                omElement.serializeAndConsume(writer);
            } else {
                omElement.serialize(writer);
            }
        } else if (busObject != null) {
            busObject = _getBOFromBO(busObject, busContext, consume);
            _outputFromBO(busObject, busContext, writer);
        }
        setConsumed(consume);
        return;
    }

    /**
     * Called if we have passed the pivot point but someone wants to output the block. The actual
     * block implementation may choose to override this setting
     */
    protected void _postPivot_outputTo(XMLStreamWriter writer)
            throws XMLStreamException, WebServiceException {
        if (log.isDebugEnabled()) {
            QName theQName = isQNameAvailable() ? getQName() : new QName("unknown");
            log.debug("The Block for " + theQName +
                    " is already consumed and therefore it is not written.");
            log.debug("If you need this block preserved, please set the " + Constants
                    .SAVE_REQUEST_MSG + " property on the MessageContext.");
        }
        return;
    }

    /**
     * Called if we have passed the pivot point but someone wants to output the block. The actual
     * block implementation may choose to override this setting.
     */
    protected XMLStreamReader _postPivot_getXMLStreamReader()
            throws XMLStreamException, WebServiceException {
        if (log.isDebugEnabled()) {
            QName theQName = isQNameAvailable() ? getQName() : new QName("unknown");
            log.debug("The Block for " + theQName +
                    " is already consumed and therefore it is only partially read.");
            log.debug("If you need this block preserved, please set the " + Constants
                    .SAVE_REQUEST_MSG + " property on the MessageContext.");
        }
        QName qName = getQName();
        String text = "";
        if (qName.getNamespaceURI().length() > 0) {
            text = "<prefix:" + qName.getLocalPart() + " xmlns:prefix='" + qName.getNamespaceURI() +
                    "'/>";
        } else {
            text = "<" + qName.getLocalPart() + "/>";
        }
        StringReader sr = new StringReader(text);
        return StAXUtils.createXMLStreamReader(sr);
    }

    /**
     * @return true if the representation of the block is currently a business object. Derived classes
     *         may use this information to get information in a performant way.
     */
    protected boolean isBusinessObject() {
        return busObject != null;
    }

    public String traceString(String indent) {
        // TODO add trace string
        return null;
    }

    /**
     * The default implementation is to return the business object. A derived block may want to
     * override this class if the business object is consumed when read (thus the dervived block may
     * want to make a buffered copy) (An example use case for overriding this method is the
     * businessObject is an InputSource)
     *
     * @param busObject
     * @param busContext
     * @param consume
     * @return
     */
    protected Object _getBOFromBO(Object busObject, Object busContext, boolean consume) {
        return busObject;
    }


    /**
     * The derived class must provide an implementation that builds the business object from the
     * reader
     *
     * @param reader     XMLStreamReader, which is consumed
     * @param busContext
     * @return
     */
    protected abstract Object _getBOFromReader(XMLStreamReader reader, Object busContext)
            throws XMLStreamException, WebServiceException;

    /**
     * Get an XMLStreamReader for the BusinessObject The derived Block must implement this method
     *
     * @param busObj
     * @param busContext
     * @return
     */
    protected abstract XMLStreamReader _getReaderFromBO(Object busObj, Object busContext)
            throws XMLStreamException, WebServiceException;

    /**
     * Output Reader contents to a Writer. The default implementation is probably sufficient for most
     * derived classes.
     *
     * @param reader
     * @param writer
     * @throws XMLStreamException
     */
    protected void _outputFromReader(XMLStreamReader reader, XMLStreamWriter writer)
            throws XMLStreamException {
        Reader2Writer r2w = new Reader2Writer(reader);
        r2w.outputTo(writer);
    }

    /**
     * Output BusinessObject contents to a Writer.
     * Derived classes must provide this implementation
     * @param busObject
     * @param busContext
     * @param writer
     * @throws XMLStreamException
     * @throws WebServiceException
     */
    protected abstract void _outputFromBO(Object busObject, Object busContext,
                                          XMLStreamWriter writer)
            throws XMLStreamException, WebServiceException;
	
}