/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The name "Apache Software Foundation" must not be used to endorse or
 *    promote products derived from this software without prior written
 *    permission. For written permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package javax.xml.transform.stream;

import javax.xml.transform.Source;

import java.io.InputStream;
import java.io.Reader;
import java.io.File;


/**
 * Acts as an holder for a transformation Source in the form
 * of a stream of XML markup.
 *
 */
public class StreamSource implements Source {

    /** 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.stream.StreamSource/feature";

    /**
     * Zero-argument default constructor. If this constructor
     * is used, and no other method is called, the transformer
     * will assume an empty input tree, with a default root node.
     */
    public StreamSource() {}

    /**
     * Construct a StreamSource from a byte stream.  Normally,
     * a stream should be used rather than a reader, so
     * the XML parser can resolve character encoding specified
     * by the XML declaration.
     *
     * <p>If this constructor is used to process a stylesheet, normally
     * setSystemId should also be called, so that relative URI references
     * can be resolved.</p>
     *
     * @param inputStream A valid InputStream reference to an XML stream.
     */
    public StreamSource(InputStream inputStream) {
        setInputStream(inputStream);
    }

    /**
     * Construct a StreamSource from a byte stream.  Normally,
     * a stream should be used rather than a reader, so that
     * the XML parser can resolve character encoding specified
     * by the XML declaration.
     *
     * <p>This constructor allows the systemID to be set in addition
     * to the input stream, which allows relative URIs
     * to be processed.</p>
     *
     * @param inputStream A valid InputStream reference to an XML stream.
     * @param systemId Must be a String that conforms to the URI syntax.
     */
    public StreamSource(InputStream inputStream, String systemId) {
        setInputStream(inputStream);
        setSystemId(systemId);
    }

    /**
     * Construct a StreamSource from a character reader.  Normally,
     * a stream should be used rather than a reader, so that
     * the XML parser can resolve character encoding specified
     * by the XML declaration.  However, in many cases the encoding
     * of the input stream is already resolved, as in the case of
     * reading XML from a StringReader.
     *
     * @param reader A valid Reader reference to an XML character stream.
     */
    public StreamSource(Reader reader) {
        setReader(reader);
    }

    /**
     * Construct a StreamSource from a character reader.  Normally,
     * a stream should be used rather than a reader, so that
     * the XML parser may resolve character encoding specified
     * by the XML declaration.  However, in many cases the encoding
     * of the input stream is already resolved, as in the case of
     * reading XML from a StringReader.
     *
     * @param reader A valid Reader reference to an XML character stream.
     * @param systemId Must be a String that conforms to the URI syntax.
     */
    public StreamSource(Reader reader, String systemId) {
        setReader(reader);
        setSystemId(systemId);
    }

    /**
     * Construct a StreamSource from a URL.
     *
     * @param systemId Must be a String that conforms to the URI syntax.
     */
    public StreamSource(String systemId) {
        this.systemId = systemId;
    }

    /**
     * Construct a StreamSource from a File.
     *
     * @param f Must a non-null File reference.
     */
    public StreamSource(File f) {
        this.systemId = "file:///" + f.getAbsolutePath();
    }

    /**
     * Set the byte stream to be used as input.  Normally,
     * a stream should be used rather than a reader, so that
     * the XML parser can resolve character encoding specified
     * by the XML declaration.
     *
     * <p>If this Source object is used to process a stylesheet, normally
     * setSystemId should also be called, so that relative URL references
     * can be resolved.</p>
     *
     * @param inputStream A valid InputStream reference to an XML stream.
     */
    public void setInputStream(InputStream inputStream) {
        this.inputStream = inputStream;
    }

    /**
     * Get the byte stream that was set with setByteStream.
     *
     * @return The byte stream that was set with setByteStream, or null
     * if setByteStream or the ByteStream constructor was not called.
     */
    public InputStream getInputStream() {
        return inputStream;
    }

    /**
     * Set the input to be a character reader.  Normally,
     * a stream should be used rather than a reader, so that
     * the XML parser can resolve character encoding specified
     * by the XML declaration.  However, in many cases the encoding
     * of the input stream is already resolved, as in the case of
     * reading XML from a StringReader.
     *
     * @param reader A valid Reader reference to an XML CharacterStream.
     */
    public void setReader(Reader reader) {
        this.reader = reader;
    }

    /**
     * Get the character stream that was set with setReader.
     *
     * @return The character stream that was set with setReader, or null
     * if setReader or the Reader constructor was not called.
     */
    public Reader getReader() {
        return reader;
    }

    /**
     * Set the public identifier for this Source.
     *
     * <p>The public identifier is always optional: if the application
     * writer includes one, it will be provided as part of the
     * location information.</p>
     *
     * @param publicId The public identifier as a string.
     */
    public void setPublicId(String publicId) {
        this.publicId = publicId;
    }

    /**
     * Get the public identifier that was set with setPublicId.
     *
     * @return The public identifier that was set with setPublicId, or null
     * if setPublicId was not called.
     */
    public String getPublicId() {
        return publicId;
    }

    /**
     * Set the system identifier for this 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
     * there is no byte stream or character stream specified).</p>
     *
     * @param systemId The system identifier as a URL string.
     */
    public void setSystemId(String systemId) {
        this.systemId = systemId;
    }

    /**
     * Get the system identifier that was set with setSystemId.
     *
     * @return The system identifier that was set with setSystemId, or null
     * if setSystemId was not called.
     */
    public String getSystemId() {
        return systemId;
    }

    /**
     * Set the system ID from a File reference.
     *
     * @param f Must a non-null File reference.
     */
    public void setSystemId(File f) {
        this.systemId = "file:///" + f.toString();
    }

    //////////////////////////////////////////////////////////////////////
    // Internal state.
    //////////////////////////////////////////////////////////////////////

    /**
     * The public identifier for this input source, or null.
     */
    private String publicId;

    /**
     * The system identifier as a URL string, or null.
     */
    private String systemId;

    /**
     * The byte stream for this Source, or null.
     */
    private InputStream inputStream;

    /**
     * The character stream for this Source, or null.
     */
    private Reader reader;
}