NilElementStreamReader.java

/*
 * 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.tuscany.sca.common.xml.stax.reader;

import javax.xml.namespace.NamespaceContext;
import javax.xml.namespace.QName;
import javax.xml.stream.Location;
import javax.xml.stream.XMLStreamException;

public class NilElementStreamReader implements XMLFragmentStreamReader {

    private static final int END_ELEMENT_STATE = 2;

    private static final int START_ELEMENT_STATE = 1;
    private int currentState = START_ELEMENT;

    private QName elementQName;

    public NilElementStreamReader(QName elementQName) {
        this.elementQName = elementQName;
    }

    public void setParentNamespaceContext(NamespaceContext nsContext) {
        // NOOP
    }

    public void close() throws XMLStreamException {
        // do nothing
    }

    public int getAttributeCount() {
        return 1;
    }

    public String getAttributeLocalName(int i) {
        return (i == 0) ? NIL_QNAME.getLocalPart() : null;
    }

    public QName getAttributeName(int i) {
        return (i == 0) ? NIL_QNAME : null;
    }

    public String getAttributeNamespace(int i) {
        return (i == 0) ? NIL_QNAME.getNamespaceURI() : null;
    }

    public String getAttributePrefix(int i) {
        return (i == 0) ? NIL_QNAME.getPrefix() : null;
    }

    public String getAttributeType(int i) {
        throw new UnsupportedOperationException();
    }

    public String getAttributeValue(int i) {
        return (i == 0) ? NIL_VALUE_TRUE : null;
    }

    public String getAttributeValue(String string, String string1) {
        if (string == null && NIL_QNAME.getLocalPart().equals(string1)) {
            return NIL_VALUE_TRUE;
        }
        return null;
    }

    public String getCharacterEncodingScheme() {
        throw new UnsupportedOperationException();
    }

    public String getElementText() throws XMLStreamException {
        return null;
    }

    public String getEncoding() {
        return null;
    }

    public int getEventType() {
        int returnEvent = START_DOCUMENT;
        switch (currentState) {
            case START_ELEMENT_STATE:
                returnEvent = START_ELEMENT;
                break;
            case END_ELEMENT_STATE:
                returnEvent = END_ELEMENT;
                break;
        }
        return returnEvent;
    }

    public String getLocalName() {
        return elementQName.getLocalPart();
    }

    public Location getLocation() {
        return new Location() {
            public int getCharacterOffset() {
                return 0;
            }

            public int getColumnNumber() {
                return 0;
            }

            public int getLineNumber() {
                return 0;
            }

            public String getPublicId() {
                return null;
            }

            public String getSystemId() {
                return null;
            }
        };
    }

    public QName getName() {
        return elementQName;
    }

    public NamespaceContext getNamespaceContext() {
        throw new UnsupportedOperationException();
    }

    public int getNamespaceCount() {
        return 0;
    }

    public String getNamespacePrefix(int i) {
        return null;
    }

    public String getNamespaceURI() {
        return elementQName.getNamespaceURI();
    }

    public String getNamespaceURI(int i) {
        return null;
    }

    public String getNamespaceURI(String string) {
        if (elementQName.getPrefix() != null && elementQName.getPrefix().equals(string)) {
            return elementQName.getNamespaceURI();
        } else {
            return null;
        }
    }

    public String getPIData() {
        throw new UnsupportedOperationException();
    }

    public String getPITarget() {
        throw new UnsupportedOperationException();
    }

    public String getPrefix() {
        return elementQName.getPrefix();
    }

    public Object getProperty(String key) throws IllegalArgumentException {
        // since optimization is a global property
        // we've to implement it everywhere
        return null;
    }

    public String getText() {
        return null;
    }

    public char[] getTextCharacters() {
        return new char[0]; 
    }

    public int getTextCharacters(int i, char[] chars, int i1, int i2) throws XMLStreamException {
        return 0;
    }

    public int getTextLength() {
        return 0;
    }

    public int getTextStart() {
        return 0;
    }

    public String getVersion() {
        throw new UnsupportedOperationException();
    }

    public boolean hasName() {
        return true;
    }

    public boolean hasNext() throws XMLStreamException {
        return currentState != END_ELEMENT_STATE;

    }

    public boolean hasText() {
        return false;
    }

    public void init() {
        // NOOP
    }

    public boolean isAttributeSpecified(int i) {
        return i == 0;
    }

    public boolean isCharacters() {
        return false;
    }

    public boolean isDone() {
        return currentState == END_ELEMENT_STATE;
    }

    public boolean isEndElement() {
        return currentState == END_ELEMENT_STATE;
    }

    public boolean isStandalone() {
        throw new UnsupportedOperationException();
    }

    public boolean isStartElement() {
        return currentState == START_ELEMENT_STATE;
    }

    public boolean isWhiteSpace() {
        return false;
    }

    public int next() throws XMLStreamException {
        int returnEvent = START_DOCUMENT;
        switch (currentState) {
            case START_ELEMENT_STATE:
                currentState = END_ELEMENT_STATE;
                returnEvent = END_ELEMENT;
                break;
            case END_ELEMENT_STATE:
                throw new XMLStreamException("parser completed!");

        }
        return returnEvent;
    }

    public int nextTag() throws XMLStreamException {
        throw new UnsupportedOperationException();
    }

    public void require(int i, String string, String string1) throws XMLStreamException {
        // nothing
    }

    public boolean standaloneSet() {
        throw new UnsupportedOperationException();
    }
}