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/*
 * Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
 * 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,
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 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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// SAX input source.
// http://www.saxproject.org
// No warranty; no copyright -- use this as you will.
// $Id: InputSource.java,v 1.2 2004/11/03 22:55:32 jsuttor Exp $

package org.xml.sax;

import java.io.IOException;
import java.io.Reader;
import java.io.InputStream;


A single input source for an XML entity.


This module, both source code and documentation, is in the
Public Domain, and comes with NO WARRANTY.
See http://www.saxproject.org
for further information.



This class allows a SAX application to encapsulate information
about an input source in a single object, which may include
a public identifier, a system identifier, a byte stream (possibly
with a specified encoding), and/or a character stream.


There are two places that the application can deliver an
input source to the parser: as the argument to the Parser.parse
method, or as the return value of the EntityResolver.resolveEntity
method.


The SAX parser will use the InputSource object to determine how
to read XML input.  If there is a character stream available, the
parser will read that stream directly, disregarding any text
encoding declaration found in that stream.
If there is no character stream, but there is
a byte stream, the parser will use that byte stream, using the
encoding specified in the InputSource or else (if no encoding is
specified) autodetecting the character encoding using an algorithm
such as the one in the XML specification.  If neither a character
stream nor a
byte stream is available, the parser will attempt to open a URI
connection to the resource identified by the system
identifier.


An InputSource object belongs to the application: the SAX parser
shall never modify it in any way (it may modify a copy if
necessary).  However, standard processing of both byte and
character streams is to close them on as part of end-of-parse cleanup,
so applications should not attempt to re-use such streams after they
have been handed to a parser.  


Author:David Megginson
See Also:
Since:1.4, SAX 1.0
/**
 * A single input source for an XML entity.
 *
 * <blockquote>
 * <em>This module, both source code and documentation, is in the
 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
 * for further information.
 * </blockquote>
 *
 * <p>This class allows a SAX application to encapsulate information
 * about an input source in a single object, which may include
 * a public identifier, a system identifier, a byte stream (possibly
 * with a specified encoding), and/or a character stream.</p>
 *
 * <p>There are two places that the application can deliver an
 * input source to the parser: as the argument to the Parser.parse
 * method, or as the return value of the EntityResolver.resolveEntity
 * method.</p>
 *
 * <p>The SAX parser will use the InputSource object to determine how
 * to read XML input.  If there is a character stream available, the
 * parser will read that stream directly, disregarding any text
 * encoding declaration found in that stream.
 * If there is no character stream, but there is
 * a byte stream, the parser will use that byte stream, using the
 * encoding specified in the InputSource or else (if no encoding is
 * specified) autodetecting the character encoding using an algorithm
 * such as the one in the XML specification.  If neither a character
 * stream nor a
 * byte stream is available, the parser will attempt to open a URI
 * connection to the resource identified by the system
 * identifier.</p>
 *
 * <p>An InputSource object belongs to the application: the SAX parser
 * shall never modify it in any way (it may modify a copy if
 * necessary).  However, standard processing of both byte and
 * character streams is to close them on as part of end-of-parse cleanup,
 * so applications should not attempt to re-use such streams after they
 * have been handed to a parser.  </p>
 *
 * @since 1.4, SAX 1.0
 * @author David Megginson
 * @see org.xml.sax.XMLReader#parse(org.xml.sax.InputSource)
 * @see org.xml.sax.EntityResolver#resolveEntity
 * @see java.io.InputStream
 * @see java.io.Reader
 */
public class InputSource {

    
Zero-argument default constructor.

See Also:
/**
     * Zero-argument default constructor.
     *
     * @see #setPublicId
     * @see #setSystemId
     * @see #setByteStream
     * @see #setCharacterStream
     * @see #setEncoding
     */
    public InputSource ()
    {
    }


    
Create a new input source with a system identifier.

Applications may use setPublicId to include a
public identifier as well, or setEncoding to specify
the character encoding, if known.


If the system identifier is a URL, it must be fully
resolved (it may not be a relative URL).


Params:
  • systemId – The system identifier (URI).
See Also:
/**
     * Create a new input source with a system identifier.
     *
     * <p>Applications may use setPublicId to include a
     * public identifier as well, or setEncoding to specify
     * the character encoding, if known.</p>
     *
     * <p>If the system identifier is a URL, it must be fully
     * resolved (it may not be a relative URL).</p>
     *
     * @param systemId The system identifier (URI).
     * @see #setPublicId
     * @see #setSystemId
     * @see #setByteStream
     * @see #setEncoding
     * @see #setCharacterStream
     */
    public InputSource (String systemId)
    {
        setSystemId(systemId);
    }


    
Create a new input source with a byte stream.

Application writers should use setSystemId() to provide a base
for resolving relative URIs, may use setPublicId to include a
public identifier, and may use setEncoding to specify the object's
character encoding.


Params:
  • byteStream – The raw byte stream containing the document.
See Also:
/**
     * Create a new input source with a byte stream.
     *
     * <p>Application writers should use setSystemId() to provide a base
     * for resolving relative URIs, may use setPublicId to include a
     * public identifier, and may use setEncoding to specify the object's
     * character encoding.</p>
     *
     * @param byteStream The raw byte stream containing the document.
     * @see #setPublicId
     * @see #setSystemId
     * @see #setEncoding
     * @see #setByteStream
     * @see #setCharacterStream
     */
    public InputSource (InputStream byteStream)
    {
        setByteStream(byteStream);
    }


    
Create a new input source with a character stream.

Application writers should use setSystemId() to provide a base
for resolving relative URIs, and may use setPublicId to include a
public identifier.


The character stream shall not include a byte order mark.


See Also:
/**
     * Create a new input source with a character stream.
     *
     * <p>Application writers should use setSystemId() to provide a base
     * for resolving relative URIs, and may use setPublicId to include a
     * public identifier.</p>
     *
     * <p>The character stream shall not include a byte order mark.</p>
     *
     * @see #setPublicId
     * @see #setSystemId
     * @see #setByteStream
     * @see #setCharacterStream
     */
    public InputSource (Reader characterStream)
    {
        setCharacterStream(characterStream);
    }


    
Set the public identifier for this input source.

The public identifier is always optional: if the application
writer includes one, it will be provided as part of the
location information.


Params:
  • publicId – The public identifier as a string.
See Also:
/**
     * Set the public identifier for this input 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.
     * @see #getPublicId
     * @see org.xml.sax.Locator#getPublicId
     * @see org.xml.sax.SAXParseException#getPublicId
     */
    public void setPublicId (String publicId)
    {
        this.publicId = publicId;
    }


    
Get the public identifier for this input source.

See Also:
Returns:The public identifier, or null if none was supplied.
/**
     * Get the public identifier for this input source.
     *
     * @return The public identifier, or null if none was supplied.
     * @see #setPublicId
     */
    public String getPublicId ()
    {
        return publicId;
    }


    
Set the system identifier for this 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
there is no byte stream or character stream specified).


If the application knows the character encoding of the
object pointed to by the system identifier, it can register
the encoding using the setEncoding method.


If the system identifier is a URL, it must be fully
resolved (it may not be a relative URL).


Params:
  • systemId – The system identifier as a string.
See Also:
/**
     * Set the system identifier for this 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
     * there is no byte stream or character stream specified).</p>
     *
     * <p>If the application knows the character encoding of the
     * object pointed to by the system identifier, it can register
     * the encoding using the setEncoding method.</p>
     *
     * <p>If the system identifier is a URL, it must be fully
     * resolved (it may not be a relative URL).</p>
     *
     * @param systemId The system identifier as a string.
     * @see #setEncoding
     * @see #getSystemId
     * @see org.xml.sax.Locator#getSystemId
     * @see org.xml.sax.SAXParseException#getSystemId
     */
    public void setSystemId (String systemId)
    {
        this.systemId = systemId;
    }


    
Get the system identifier for this input source.

The getEncoding method will return the character encoding
of the object pointed to, or null if unknown.


If the system ID is a URL, it will be fully resolved.


See Also:
Returns:The system identifier, or null if none was supplied.
/**
     * Get the system identifier for this input source.
     *
     * <p>The getEncoding method will return the character encoding
     * of the object pointed to, or null if unknown.</p>
     *
     * <p>If the system ID is a URL, it will be fully resolved.</p>
     *
     * @return The system identifier, or null if none was supplied.
     * @see #setSystemId
     * @see #getEncoding
     */
    public String getSystemId ()
    {
        return systemId;
    }


    
Set the byte stream for this input source.

The SAX parser will ignore this if there is also a character
stream specified, but it will use a byte stream in preference
to opening a URI connection itself.


If the application knows the character encoding of the
byte stream, it should set it with the setEncoding method.


Params:
  • byteStream – A byte stream containing an XML document or
       other entity.
See Also:
/**
     * Set the byte stream for this input source.
     *
     * <p>The SAX parser will ignore this if there is also a character
     * stream specified, but it will use a byte stream in preference
     * to opening a URI connection itself.</p>
     *
     * <p>If the application knows the character encoding of the
     * byte stream, it should set it with the setEncoding method.</p>
     *
     * @param byteStream A byte stream containing an XML document or
     *        other entity.
     * @see #setEncoding
     * @see #getByteStream
     * @see #getEncoding
     * @see java.io.InputStream
     */
    public void setByteStream (InputStream byteStream)
    {
        this.byteStream = byteStream;
    }


    
Get the byte stream for this input source.

The getEncoding method will return the character
encoding for this byte stream, or null if unknown.


See Also:
Returns:The byte stream, or null if none was supplied.
/**
     * Get the byte stream for this input source.
     *
     * <p>The getEncoding method will return the character
     * encoding for this byte stream, or null if unknown.</p>
     *
     * @return The byte stream, or null if none was supplied.
     * @see #getEncoding
     * @see #setByteStream
     */
    public InputStream getByteStream ()
    {
        return byteStream;
    }


    
Set the character encoding, if known.

The encoding must be a string acceptable for an
XML encoding declaration (see section 4.3.3 of the XML 1.0
recommendation).


This method has no effect when the application provides a
character stream.


Params:
  • encoding – A string describing the character encoding.
See Also:
/**
     * Set the character encoding, if known.
     *
     * <p>The encoding must be a string acceptable for an
     * XML encoding declaration (see section 4.3.3 of the XML 1.0
     * recommendation).</p>
     *
     * <p>This method has no effect when the application provides a
     * character stream.</p>
     *
     * @param encoding A string describing the character encoding.
     * @see #setSystemId
     * @see #setByteStream
     * @see #getEncoding
     */
    public void setEncoding (String encoding)
    {
        this.encoding = encoding;
    }


    
Get the character encoding for a byte stream or URI.
This value will be ignored when the application provides a
character stream.

See Also:
Returns:The encoding, or null if none was supplied.
/**
     * Get the character encoding for a byte stream or URI.
     * This value will be ignored when the application provides a
     * character stream.
     *
     * @return The encoding, or null if none was supplied.
     * @see #setByteStream
     * @see #getSystemId
     * @see #getByteStream
     */
    public String getEncoding ()
    {
        return encoding;
    }


    
Set the character stream for this input source.

If there is a character stream specified, the SAX parser
will ignore any byte stream and will not attempt to open
a URI connection to the system identifier.


Params:
  • characterStream – The character stream containing the
       XML document or other entity.
See Also:
/**
     * Set the character stream for this input source.
     *
     * <p>If there is a character stream specified, the SAX parser
     * will ignore any byte stream and will not attempt to open
     * a URI connection to the system identifier.</p>
     *
     * @param characterStream The character stream containing the
     *        XML document or other entity.
     * @see #getCharacterStream
     * @see java.io.Reader
     */
    public void setCharacterStream (Reader characterStream)
    {
        this.characterStream = characterStream;
    }


    
Get the character stream for this input source.

See Also:
Returns:The character stream, or null if none was supplied.
/**
     * Get the character stream for this input source.
     *
     * @return The character stream, or null if none was supplied.
     * @see #setCharacterStream
     */
    public Reader getCharacterStream ()
    {
        return characterStream;
    }

    
Indicates whether the InputSource object is empty. Empty is defined as follows: 
    

  • All of the input sources, including the public identifier, system identifier, byte stream, and character stream, are null. 
    • 

  • The public identifier and system identifier are null, and byte and character stream are either null or contain no byte or character. 
    
Note that this method will reset the byte stream if it is provided, or
the character stream if the byte stream is not provided.

    • 




In case of error while checking the byte or character stream, the method
will return false to allow the XML processor to handle the error.

Returns:true if the InputSource object is empty, false otherwise
/**
     * Indicates whether the {@code InputSource} object is empty. Empty is
     * defined as follows:
     * <ul>
     * <li>All of the input sources, including the public identifier, system
     * identifier, byte stream, and character stream, are {@code null}.
     * </li>
     * <li>The public identifier and system identifier are  {@code null}, and
     * byte and character stream are either  {@code null} or contain no byte
     * or character.
     * <p>
     * Note that this method will reset the byte stream if it is provided, or
     * the character stream if the byte stream is not provided.
     * </li>
     * </ul>
     * <p>
     * In case of error while checking the byte or character stream, the method
     * will return false to allow the XML processor to handle the error.
     *
     * @return true if the {@code InputSource} object is empty, false otherwise
     */
    public boolean isEmpty() {
        return (publicId == null && systemId == null && isStreamEmpty());
    }

    private boolean isStreamEmpty() {
        boolean empty = true;
        try {
            if (byteStream != null) {
                byteStream.reset();
                int bytesRead = byteStream.available();
                if (bytesRead > 0) {
                    return false;
                }
            }

            if (characterStream != null) {
                characterStream.reset();
                int c = characterStream.read();
                characterStream.reset();
                if (c != -1) {
                    return false;
                }
            }
        } catch (IOException ex) {
            //in case of error, return false
            return false;
        }

        return empty;
    }
    ////////////////////////////////////////////////////////////////////
    // Internal state.
    ////////////////////////////////////////////////////////////////////

    private String publicId;
    private String systemId;
    private InputStream byteStream;
    private String encoding;
    private Reader characterStream;

}

// end of InputSource.java