1 /*
   2  * Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.xml.transform.sax;
  27 
  28 import javax.xml.transform.Source;
  29 import javax.xml.transform.stream.StreamSource;
  30 
  31 import org.xml.sax.InputSource;
  32 import org.xml.sax.XMLReader;
  33 
  34 /**
  35  * <p>Acts as an holder for SAX-style Source.</p>
  36  *
  37  * <p>Note that XSLT requires namespace support. Attempting to transform an
  38  * input source that is not
  39  * generated with a namespace-aware parser may result in errors.
  40  * Parsers can be made namespace aware by calling the
  41  * {@link javax.xml.parsers.SAXParserFactory#setNamespaceAware(boolean awareness)} method.</p>
  42  *
  43  * @author Jeff Suttor
  44  * @since 1.4
  45  */
  46 public class SAXSource implements Source {
  47 
  48     /**
  49      * If {@link javax.xml.transform.TransformerFactory#getFeature}
  50      * returns true when passed this value as an argument,
  51      * the Transformer supports Source input of this type.
  52      */
  53     public static final String FEATURE =
  54         "http://javax.xml.transform.sax.SAXSource/feature";
  55 
  56     /**
  57      * <p>Zero-argument default constructor.  If this constructor is used, and
  58      * no SAX source is set using
  59      * {@link #setInputSource(InputSource inputSource)} , then the
  60      * <code>Transformer</code> will
  61      * create an empty source {@link org.xml.sax.InputSource} using
  62      * {@link org.xml.sax.InputSource#InputSource() new InputSource()}.</p>
  63      *
  64      * @see javax.xml.transform.Transformer#transform(Source xmlSource, Result outputTarget)
  65      */
  66     public SAXSource() { }
  67 
  68     /**
  69      * Create a <code>SAXSource</code>, using an {@link org.xml.sax.XMLReader}
  70      * and a SAX InputSource. The {@link javax.xml.transform.Transformer}
  71      * or {@link javax.xml.transform.sax.SAXTransformerFactory} will set itself
  72      * to be the reader's {@link org.xml.sax.ContentHandler}, and then will call
  73      * reader.parse(inputSource).
  74      *
  75      * @param reader An XMLReader to be used for the parse.
  76      * @param inputSource A SAX input source reference that must be non-null
  77      * and that will be passed to the reader parse method.
  78      */
  79     public SAXSource(XMLReader reader, InputSource inputSource) {
  80         this.reader      = reader;
  81         this.inputSource = inputSource;
  82     }
  83 
  84     /**
  85      * Create a <code>SAXSource</code>, using a SAX <code>InputSource</code>.
  86      * The {@link javax.xml.transform.Transformer} or
  87      * {@link javax.xml.transform.sax.SAXTransformerFactory} creates a
  88      * reader (if setXMLReader is not used), sets itself as
  89      * the reader's {@link org.xml.sax.ContentHandler}, and calls
  90      * reader.parse(inputSource).
  91      *
  92      * @param inputSource An input source reference that must be non-null
  93      * and that will be passed to the parse method of the reader.
  94      */
  95     public SAXSource(InputSource inputSource) {
  96         this.inputSource = inputSource;
  97     }
  98 
  99     /**
 100      * Set the XMLReader to be used for the Source.
 101      *
 102      * @param reader A valid XMLReader or XMLFilter reference.
 103      */
 104     public void setXMLReader(XMLReader reader) {
 105         this.reader = reader;
 106     }
 107 
 108     /**
 109      * Get the XMLReader to be used for the Source.
 110      *
 111      * @return A valid XMLReader or XMLFilter reference, or null.
 112      */
 113     public XMLReader getXMLReader() {
 114         return reader;
 115     }
 116 
 117     /**
 118      * Set the SAX InputSource to be used for the Source.
 119      *
 120      * @param inputSource A valid InputSource reference.
 121      */
 122     public void setInputSource(InputSource inputSource) {
 123         this.inputSource = inputSource;
 124     }
 125 
 126     /**
 127      * Get the SAX InputSource to be used for the Source.
 128      *
 129      * @return A valid InputSource reference, or null.
 130      */
 131     public InputSource getInputSource() {
 132         return inputSource;
 133     }
 134 
 135     /**
 136      * Set the system identifier for this Source.  If an input source
 137      * has already been set, it will set the system ID or that
 138      * input source, otherwise it will create a new input source.
 139      *
 140      * <p>The system identifier is optional if there is a byte stream
 141      * or a character stream, but it is still useful to provide one,
 142      * since the application can use it to resolve relative URIs
 143      * and can include it in error messages and warnings (the parser
 144      * will attempt to open a connection to the URI only if
 145      * no byte stream or character stream is specified).</p>
 146      *
 147      * @param systemId The system identifier as a URI string.
 148      */
 149     @Override
 150     public void setSystemId(String systemId) {
 151 
 152         if (null == inputSource) {
 153             inputSource = new InputSource(systemId);
 154         } else {
 155             inputSource.setSystemId(systemId);
 156         }
 157     }
 158 
 159     /**
 160      * <p>Get the base ID (URI or system ID) from where URIs
 161      * will be resolved.</p>
 162      *
 163      * @return Base URL for the <code>Source</code>, or <code>null</code>.
 164      */
 165     @Override
 166     public String getSystemId() {
 167 
 168         if (inputSource == null) {
 169             return null;
 170         } else {
 171             return inputSource.getSystemId();
 172         }
 173     }
 174 
 175     /**
 176      * The XMLReader to be used for the source tree input. May be null.
 177      */
 178     private XMLReader reader;
 179 
 180     /**
 181      * <p>The SAX InputSource to be used for the source tree input.
 182      * Should not be <code>null</code>.</p>
 183      */
 184     private InputSource inputSource;
 185 
 186     /**
 187      * Attempt to obtain a SAX InputSource object from a Source
 188      * object.
 189      *
 190      * @param source Must be a non-null Source reference.
 191      *
 192      * @return An InputSource, or null if Source can not be converted.
 193      */
 194     public static InputSource sourceToInputSource(Source source) {
 195 
 196         if (source instanceof SAXSource) {
 197             return ((SAXSource) source).getInputSource();
 198         } else if (source instanceof StreamSource) {
 199             StreamSource ss      = (StreamSource) source;
 200             InputSource  isource = new InputSource(ss.getSystemId());
 201 
 202             isource.setByteStream(ss.getInputStream());
 203             isource.setCharacterStream(ss.getReader());
 204             isource.setPublicId(ss.getPublicId());
 205 
 206             return isource;
 207         } else {
 208             return null;
 209         }
 210     }
 211 
 212     /**
 213      * Indicates whether the {@code SAXSource} object is empty. Empty is
 214      * defined as follows:
 215      * <ul>
 216      * <li>if the system identifier and {@code InputSource} are {@code null};
 217      * </li>
 218      * <li>if the system identifier is {@code null}, and the {@code InputSource}
 219      * is empty.
 220      * </li>
 221      * </ul>
 222      *
 223      * @return true if the {@code SAXSource} object is empty, false otherwise
 224      */
 225     @Override
 226     public boolean isEmpty() {
 227         return getSystemId() == null && (inputSource == null || inputSource.isEmpty());
 228     }
 229 }