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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package com.sun.xml.internal.bind.v2.runtime.output;

import java.io.IOException;

import java.lang.reflect.Constructor;

import javax.xml.stream.XMLStreamException;

import javax.xml.stream.XMLStreamWriter;

import com.sun.xml.internal.bind.v2.runtime.JAXBContextImpl;

import com.sun.xml.internal.bind.v2.runtime.XMLSerializer;

import com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl;

import org.xml.sax.SAXException;

/**

 * {@link XmlOutput} that writes to StAX {@link XMLStreamWriter}.

 * <p>

 * TODO:

 * Finding the optimized FI implementations is a bit hacky and not very

 * extensible. Can we use the service provider mechanism in general for

 * concrete implementations of XmlOutputAbstractImpl.

 *

 * @author Kohsuke Kawaguchi

 */

public class XMLStreamWriterOutput extends XmlOutputAbstractImpl {

    /**

     * Creates a new {@link XmlOutput} from a {@link XMLStreamWriter}.

     * This method recognizes an FI StAX writer.

     */

    public static XmlOutput create(XMLStreamWriter out, JAXBContextImpl context) {

        // try optimized path

        final Class writerClass = out.getClass();

        if (writerClass==FI_STAX_WRITER_CLASS) {

            try {

                return FI_OUTPUT_CTOR.newInstance(out, context);

            } catch (Exception e) {

            }

        }

        if (STAXEX_WRITER_CLASS!=null && STAXEX_WRITER_CLASS.isAssignableFrom(writerClass)) {

            try {

                return STAXEX_OUTPUT_CTOR.newInstance(out);

            } catch (Exception e) {

            }

        }

        // otherwise the normal writer.

        return new XMLStreamWriterOutput(out);

    }

    private final XMLStreamWriter out;

    protected final char[] buf = new char[256];

    protected XMLStreamWriterOutput(XMLStreamWriter out) {

        this.out = out;

    }

    // not called if we are generating fragments

    @Override

    public void startDocument(XMLSerializer serializer, boolean fragment, int[] nsUriIndex2prefixIndex, NamespaceContextImpl nsContext) throws IOException, SAXException, XMLStreamException {

        super.startDocument(serializer, fragment,nsUriIndex2prefixIndex,nsContext);

        if(!fragment)

            out.writeStartDocument();

    }

    @Override

    public void endDocument(boolean fragment) throws IOException, SAXException, XMLStreamException {

        if(!fragment) {

            out.writeEndDocument();

            out.flush();

        }

        super.endDocument(fragment);

    }

    public void beginStartTag(int prefix, String localName) throws IOException, XMLStreamException {

        out.writeStartElement(

            nsContext.getPrefix(prefix),

            localName,

            nsContext.getNamespaceURI(prefix));

        NamespaceContextImpl.Element nse = nsContext.getCurrent();

        if(nse.count()>0) {

            for( int i=nse.count()-1; i>=0; i-- ) {

                String uri = nse.getNsUri(i);

                if(uri.length()==0 && nse.getBase()==1)

                    continue;   // no point in definint xmlns='' on the root

                out.writeNamespace(nse.getPrefix(i),uri);

            }

        }

    }

    public void attribute(int prefix, String localName, String value) throws IOException, XMLStreamException {

        if(prefix==-1)

            out.writeAttribute(localName,value);

        else

            out.writeAttribute(

                    nsContext.getPrefix(prefix),

                    nsContext.getNamespaceURI(prefix),

                    localName, value);

    }

    public void endStartTag() throws IOException, SAXException {

        // noop

    }

    public void endTag(int prefix, String localName) throws IOException, SAXException, XMLStreamException {

        out.writeEndElement();

    }

    public void text(String value, boolean needsSeparatingWhitespace) throws IOException, SAXException, XMLStreamException {

        if(needsSeparatingWhitespace)

            out.writeCharacters(" ");

        out.writeCharacters(value);

    }

    public void text(Pcdata value, boolean needsSeparatingWhitespace) throws IOException, SAXException, XMLStreamException {

        if(needsSeparatingWhitespace)

            out.writeCharacters(" ");

        int len = value.length();

        if(len <buf.length) {

            value.writeTo(buf,0);

            out.writeCharacters(buf,0,len);

        } else {

            out.writeCharacters(value.toString());

        }

    }

    /**

     * Reference to FI's XMLStreamWriter class, if FI can be loaded.

     */

    private static final Class FI_STAX_WRITER_CLASS = initFIStAXWriterClass();

    private static final Constructor<? extends XmlOutput> FI_OUTPUT_CTOR = initFastInfosetOutputClass();

    private static Class initFIStAXWriterClass() {

        try {

            ClassLoader loader = getClassLoader();

            Class llfisw = Class.forName("com.sun.xml.internal.org.jvnet.fastinfoset.stax.LowLevelFastInfosetStreamWriter", true, loader);

            Class sds = loader.loadClass("com.sun.xml.internal.fastinfoset.stax.StAXDocumentSerializer");

            // Check if StAXDocumentSerializer implements LowLevelFastInfosetStreamWriter

            if (llfisw.isAssignableFrom(sds))

                return sds;

            else

                return null;

        } catch (Throwable e) {

            return null;

        }

    }

    private static Constructor<? extends XmlOutput> initFastInfosetOutputClass() {

        try {

            if (FI_STAX_WRITER_CLASS == null)

                return null;

            ClassLoader loader = getClassLoader();

            Class c = Class.forName("com.sun.xml.internal.bind.v2.runtime.output.FastInfosetStreamWriterOutput", true, loader);

            return c.getConstructor(FI_STAX_WRITER_CLASS, JAXBContextImpl.class);

        } catch (Throwable e) {

            return null;

        }

    }

    //

    // StAX-ex

    //

    private static final Class STAXEX_WRITER_CLASS = initStAXExWriterClass();

    private static final Constructor<? extends XmlOutput> STAXEX_OUTPUT_CTOR = initStAXExOutputClass();

    private static Class initStAXExWriterClass() {

        try {

            ClassLoader loader = getClassLoader();

            return Class.forName("com.sun.xml.internal.org.jvnet.staxex.XMLStreamWriterEx",true,loader);

        } catch (Throwable e) {

            return null;

        }

    }

    private static Constructor<? extends XmlOutput> initStAXExOutputClass() {

        try {

            ClassLoader loader = getClassLoader();

            Class c = Class.forName("com.sun.xml.internal.bind.v2.runtime.output.StAXExStreamWriterOutput",true, loader);

            return c.getConstructor(STAXEX_WRITER_CLASS);

        } catch (Throwable e) {

            return null;

        }

    }

    private static ClassLoader getClassLoader() {

        ClassLoader cl = SecureLoader.getClassClassLoader(UnmarshallerImpl.class);

        if (cl == null) {

            cl = SecureLoader.getContextClassLoader();

        }

        return cl;

    }

}