/*
 * 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.
 */

// $Id: SAXSource.java 446598 2006-09-15 12:55:40Z jeremias $

package javax.xml.transform.sax;

import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

Acts as an holder for SAX-style Source.
Note that XSLT requires namespace support. Attempting to transform an input source that is not generated with a namespace-aware parser may result in errors. Parsers can be made namespace aware by calling the SAXParserFactory.setNamespaceAware(boolean awareness) method.
Author:
Jeff Suttor
Version:
$Revision: 446598 $, $Date: 2006-09-15 08:55:40 -0400 (Fri, 15 Sep 2006) $/**
 * <p>Acts as an holder for SAX-style Source.</p>
 * 
 * <p>Note that XSLT requires namespace support. Attempting to transform an
 * input source that is not
 * generated with a namespace-aware parser may result in errors.
 * Parsers can be made namespace aware by calling the
 * {@link javax.xml.parsers.SAXParserFactory#setNamespaceAware(boolean awareness)} method.</p>
 * 
 * @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
 * @version $Revision: 446598 $, $Date: 2006-09-15 08:55:40 -0400 (Fri, 15 Sep 2006) $
 */
public class SAXSource implements Source {

    
If TransformerFactory.getFeature returns true when passed this value as an argument, the Transformer supports Source input of this type. /**
     * If {@link javax.xml.transform.TransformerFactory#getFeature}
     * returns true when passed this value as an argument,
     * the Transformer supports Source input of this type.
     */
    public static final String FEATURE =
        "http://javax.xml.transform.sax.SAXSource/feature";

    
Zero-argument default constructor. If this constructor is used, and no SAX source is set using setInputSource(InputSource inputSource) , then the Transformer will create an empty source InputSource using new InputSource().
See Also:
Transformer.transform(Source xmlSource, Result outputTarget)/**
     * <p>Zero-argument default constructor.  If this constructor is used, and
     * no SAX source is set using
     * {@link #setInputSource(InputSource inputSource)} , then the
     * <code>Transformer</code> will
     * create an empty source {@link org.xml.sax.InputSource} using
     * {@link org.xml.sax.InputSource#InputSource() new InputSource()}.</p>
     *
     * @see javax.xml.transform.Transformer#transform(Source xmlSource, Result outputTarget)
     */
    public SAXSource() { }

    
Create a SAXSource, using an XMLReader and a SAX InputSource. The Transformer or SAXTransformerFactory will set itself to be the reader's ContentHandler, and then will call reader.parse(inputSource). 
Params:
reader – An XMLReader to be used for the parse.
inputSource – A SAX input source reference that must be non-null
and that will be passed to the reader parse method./**
     * Create a <code>SAXSource</code>, using an {@link org.xml.sax.XMLReader}
     * and a SAX InputSource. The {@link javax.xml.transform.Transformer}
     * or {@link javax.xml.transform.sax.SAXTransformerFactory} will set itself
     * to be the reader's {@link org.xml.sax.ContentHandler}, and then will call
     * reader.parse(inputSource).
     *
     * @param reader An XMLReader to be used for the parse.
     * @param inputSource A SAX input source reference that must be non-null
     * and that will be passed to the reader parse method.
     */
    public SAXSource(XMLReader reader, InputSource inputSource) {
        this.reader      = reader;
        this.inputSource = inputSource;
    }

    
Create a SAXSource, using a SAX InputSource. The Transformer or SAXTransformerFactory creates a reader via XMLReaderFactory (if setXMLReader is not used), sets itself as the reader's ContentHandler, and calls reader.parse(inputSource). 
Params:
inputSource – An input source reference that must be non-null
and that will be passed to the parse method of the reader./**
     * Create a <code>SAXSource</code>, using a SAX <code>InputSource</code>.
     * The {@link javax.xml.transform.Transformer} or
     * {@link javax.xml.transform.sax.SAXTransformerFactory} creates a
     * reader via {@link org.xml.sax.helpers.XMLReaderFactory}
     * (if setXMLReader is not used), sets itself as
     * the reader's {@link org.xml.sax.ContentHandler}, and calls
     * reader.parse(inputSource).
     *
     * @param inputSource An input source reference that must be non-null
     * and that will be passed to the parse method of the reader.
     */
    public SAXSource(InputSource inputSource) {
        this.inputSource = inputSource;
    }

    
Set the XMLReader to be used for the Source.
Params:
reader – A valid XMLReader or XMLFilter reference./**
     * Set the XMLReader to be used for the Source.
     *
     * @param reader A valid XMLReader or XMLFilter reference.
     */
    public void setXMLReader(XMLReader reader) {
        this.reader = reader;
    }

    
Get the XMLReader to be used for the Source.
Returns:
A valid XMLReader or XMLFilter reference, or null./**
     * Get the XMLReader to be used for the Source.
     *
     * @return A valid XMLReader or XMLFilter reference, or null.
     */
    public XMLReader getXMLReader() {
        return reader;
    }

    
Set the SAX InputSource to be used for the Source.
Params:
inputSource – A valid InputSource reference./**
     * Set the SAX InputSource to be used for the Source.
     *
     * @param inputSource A valid InputSource reference.
     */
    public void setInputSource(InputSource inputSource) {
        this.inputSource = inputSource;
    }

    
Get the SAX InputSource to be used for the Source.
Returns:
A valid InputSource reference, or null./**
     * Get the SAX InputSource to be used for the Source.
     *
     * @return A valid InputSource reference, or null.
     */
    public InputSource getInputSource() {
        return inputSource;
    }

    
Set the system identifier for this Source.  If an input source
has already been set, it will set the system ID or that
input source, otherwise it will create a new input source.
The system identifier is optional if there is a byte stream
or a character stream, but it is still useful to provide one,
since the application can use it to resolve relative URIs
and can include it in error messages and warnings (the parser
will attempt to open a connection to the URI only if
no byte stream or character stream is specified).
Params:
systemId – The system identifier as a URI string./**
     * Set the system identifier for this Source.  If an input source
     * has already been set, it will set the system ID or that
     * input source, otherwise it will create a new input source.
     *
     * <p>The system identifier is optional if there is a byte stream
     * or a character stream, but it is still useful to provide one,
     * since the application can use it to resolve relative URIs
     * and can include it in error messages and warnings (the parser
     * will attempt to open a connection to the URI only if
     * no byte stream or character stream is specified).</p>
     *
     * @param systemId The system identifier as a URI string.
     */
    public void setSystemId(String systemId) {

        if (null == inputSource) {
            inputSource = new InputSource(systemId);
        } else {
            inputSource.setSystemId(systemId);
        }
    }

    
Get the base ID (URI or system ID) from where URIs
will be resolved.
Returns:
Base URL for the Source, or null./**
     * <p>Get the base ID (URI or system ID) from where URIs
     * will be resolved.</p>
     *
     * @return Base URL for the <code>Source</code>, or <code>null</code>.
     */
    public String getSystemId() {

        if (inputSource == null) {
            return null;
        } else {
            return inputSource.getSystemId();
        }
    }

    
The XMLReader to be used for the source tree input. May be null.
/**
     * The XMLReader to be used for the source tree input. May be null.
     */
    private XMLReader reader;

    
The SAX InputSource to be used for the source tree input.
Should not be null.

/**
     * <p>The SAX InputSource to be used for the source tree input.
     * Should not be <code>null<code>.</p>
     */
    private InputSource inputSource;

    
Attempt to obtain a SAX InputSource object from a Source
object.
Params:
source – Must be a non-null Source reference.
Returns:
An InputSource, or null if Source can not be converted./**
     * Attempt to obtain a SAX InputSource object from a Source
     * object.
     *
     * @param source Must be a non-null Source reference.
     *
     * @return An InputSource, or null if Source can not be converted.
     */
    public static InputSource sourceToInputSource(Source source) {

        if (source instanceof SAXSource) {
            return ((SAXSource) source).getInputSource();
        } else if (source instanceof StreamSource) {
            StreamSource ss      = (StreamSource) source;
            InputSource  isource = new InputSource(ss.getSystemId());

            isource.setByteStream(ss.getInputStream());
            isource.setCharacterStream(ss.getReader());
            isource.setPublicId(ss.getPublicId());

            return isource;
        } else {
            return null;
        }
    }
}