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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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 * THIS FILE WAS MODIFIED BY SUN MICROSYSTEMS, INC.

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package com.sun.xml.internal.fastinfoset.stax.events;

import com.sun.xml.internal.fastinfoset.stax.*;

import java.util.NoSuchElementException;

import javax.xml.stream.XMLInputFactory;

import javax.xml.stream.XMLStreamException;

import javax.xml.stream.XMLStreamReader;

import javax.xml.stream.events.XMLEvent;

import javax.xml.stream.util.XMLEventAllocator;

import com.sun.xml.internal.fastinfoset.CommonResourceBundle;

public class StAXEventReader implements javax.xml.stream.XMLEventReader{

    protected XMLStreamReader _streamReader ;

    protected XMLEventAllocator _eventAllocator;

    private XMLEvent _currentEvent;     //the current event

    private XMLEvent[] events = new XMLEvent[3];

    private int size = 3;

    private int currentIndex = 0;

    private boolean hasEvent = false;   //true when current event exists, false initially & at end

    //only constructor will do because we delegate everything to underlying XMLStreamReader

    public StAXEventReader(XMLStreamReader reader) throws  XMLStreamException {

        _streamReader = reader ;

        _eventAllocator = (XMLEventAllocator)reader.getProperty(XMLInputFactory.ALLOCATOR);

        if(_eventAllocator == null){

            _eventAllocator = new StAXEventAllocatorBase();

        }

        //initialize

        if (_streamReader.hasNext())

        {

            _streamReader.next();

            _currentEvent =_eventAllocator.allocate(_streamReader);

            events[0] = _currentEvent;

            hasEvent = true;

        } else {

            throw new XMLStreamException(CommonResourceBundle.getInstance().getString("message.noElement"));

        }

    }

    public boolean hasNext() {

        return hasEvent;

    }

    public XMLEvent nextEvent() throws XMLStreamException {

        XMLEvent event = null;

        XMLEvent nextEvent = null;

        if (hasEvent)

        {

            event = events[currentIndex];

            events[currentIndex] = null;

            if (_streamReader.hasNext())

            {

                //advance and read the next

                _streamReader.next();

                nextEvent = _eventAllocator.allocate(_streamReader);

                if (++currentIndex==size)

                    currentIndex = 0;

                events[currentIndex] = nextEvent;

                hasEvent = true;

            } else {

                _currentEvent = null;

                hasEvent = false;

            }

            return event;

        }

        else{

            throw new NoSuchElementException();

        }

    }

    public void remove(){

        //stream reader is read-only.

        throw new java.lang.UnsupportedOperationException();

    }

    public void close() throws XMLStreamException {

        _streamReader.close();

    }

    /** Reads the content of a text-only element. Precondition:

     * the current event is START_ELEMENT. Postcondition:

     * The current event is the corresponding END_ELEMENT.

     * @throws XMLStreamException if the current event is not a START_ELEMENT

     * or if a non text element is encountered

     */

    public String getElementText() throws XMLStreamException {

        if(!hasEvent) {

            throw new NoSuchElementException();

        }

        if(!_currentEvent.isStartElement()) {

            StAXDocumentParser parser = (StAXDocumentParser)_streamReader;

            return parser.getElementText(true);

        } else {

            return _streamReader.getElementText();

        }

    }

    /** Get the value of a feature/property from the underlying implementation

     * @param name The name of the property

     * @return The value of the property

     * @throws IllegalArgumentException if the property is not supported

     */

    public Object getProperty(java.lang.String name) throws java.lang.IllegalArgumentException {

        return _streamReader.getProperty(name) ;

    }

    /** Skips any insignificant space events until a START_ELEMENT or

     * END_ELEMENT is reached. If anything other than space characters are

     * encountered, an exception is thrown. This method should

     * be used when processing element-only content because

     * the parser is not able to recognize ignorable whitespace if

     * the DTD is missing or not interpreted.

     * @throws XMLStreamException if anything other than space characters are encountered

     */

    public XMLEvent nextTag() throws XMLStreamException {

        if(!hasEvent) {

            throw new NoSuchElementException();

        }

        StAXDocumentParser parser = (StAXDocumentParser)_streamReader;

        parser.nextTag(true);

        return _eventAllocator.allocate(_streamReader);

    }

    //XMLEventReader extends Iterator;

    public Object next() {

        try{

            return nextEvent();

        }catch(XMLStreamException streamException){

            return null;

        }

    }

    public XMLEvent peek() throws XMLStreamException{

        if (!hasEvent)

             throw new XMLStreamException(CommonResourceBundle.getInstance().getString("message.noElement"));

        _currentEvent = events[currentIndex];

        return _currentEvent;

    }

    public void setAllocator(XMLEventAllocator allocator) {

        if (allocator == null)

            throw new IllegalArgumentException(CommonResourceBundle.getInstance().getString("message.nullXMLEventAllocator"));

        _eventAllocator = allocator;

    }

}