001 // SAX error handler.
002 // http://www.saxproject.org
003 // No warranty; no copyright -- use this as you will.
004 // $Id: ErrorHandler.java,v 1.1 2004/12/23 22:38:42 mark Exp $
005
006 package org.xml.sax;
007
008
009 /**
010 * Basic interface for SAX error handlers.
011 *
012 * <blockquote>
013 * <em>This module, both source code and documentation, is in the
014 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
015 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
016 * for further information.
017 * </blockquote>
018 *
019 * <p>If a SAX application needs to implement customized error
020 * handling, it must implement this interface and then register an
021 * instance with the XML reader using the
022 * {@link org.xml.sax.XMLReader#setErrorHandler setErrorHandler}
023 * method. The parser will then report all errors and warnings
024 * through this interface.</p>
025 *
026 * <p><strong>WARNING:</strong> If an application does <em>not</em>
027 * register an ErrorHandler, XML parsing errors will go unreported,
028 * except that <em>SAXParseException</em>s will be thrown for fatal errors.
029 * In order to detect validity errors, an ErrorHandler that does something
030 * with {@link #error error()} calls must be registered.</p>
031 *
032 * <p>For XML processing errors, a SAX driver must use this interface
033 * in preference to throwing an exception: it is up to the application
034 * to decide whether to throw an exception for different types of
035 * errors and warnings. Note, however, that there is no requirement that
036 * the parser continue to report additional errors after a call to
037 * {@link #fatalError fatalError}. In other words, a SAX driver class
038 * may throw an exception after reporting any fatalError.
039 * Also parsers may throw appropriate exceptions for non-XML errors.
040 * For example, {@link XMLReader#parse XMLReader.parse()} would throw
041 * an IOException for errors accessing entities or the document.</p>
042 *
043 * @since SAX 1.0
044 * @author David Megginson
045 * @version 2.0.1+ (sax2r3pre1)
046 * @see org.xml.sax.XMLReader#setErrorHandler
047 * @see org.xml.sax.SAXParseException
048 */
049 public interface ErrorHandler {
050
051
052 /**
053 * Receive notification of a warning.
054 *
055 * <p>SAX parsers will use this method to report conditions that
056 * are not errors or fatal errors as defined by the XML
057 * recommendation. The default behaviour is to take no
058 * action.</p>
059 *
060 * <p>The SAX parser must continue to provide normal parsing events
061 * after invoking this method: it should still be possible for the
062 * application to process the document through to the end.</p>
063 *
064 * <p>Filters may use this method to report other, non-XML warnings
065 * as well.</p>
066 *
067 * @param exception The warning information encapsulated in a
068 * SAX parse exception.
069 * @exception org.xml.sax.SAXException Any SAX exception, possibly
070 * wrapping another exception.
071 * @see org.xml.sax.SAXParseException
072 */
073 public abstract void warning (SAXParseException exception)
074 throws SAXException;
075
076
077 /**
078 * Receive notification of a recoverable error.
079 *
080 * <p>This corresponds to the definition of "error" in section 1.2
081 * of the W3C XML 1.0 Recommendation. For example, a validating
082 * parser would use this callback to report the violation of a
083 * validity constraint. The default behaviour is to take no
084 * action.</p>
085 *
086 * <p>The SAX parser must continue to provide normal parsing
087 * events after invoking this method: it should still be possible
088 * for the application to process the document through to the end.
089 * If the application cannot do so, then the parser should report
090 * a fatal error even if the XML recommendation does not require
091 * it to do so.</p>
092 *
093 * <p>Filters may use this method to report other, non-XML errors
094 * as well.</p>
095 *
096 * @param exception The error information encapsulated in a
097 * SAX parse exception.
098 * @exception org.xml.sax.SAXException Any SAX exception, possibly
099 * wrapping another exception.
100 * @see org.xml.sax.SAXParseException
101 */
102 public abstract void error (SAXParseException exception)
103 throws SAXException;
104
105
106 /**
107 * Receive notification of a non-recoverable error.
108 *
109 * <p><strong>There is an apparent contradiction between the
110 * documentation for this method and the documentation for {@link
111 * org.xml.sax.ContentHandler#endDocument}. Until this ambiguity
112 * is resolved in a future major release, clients should make no
113 * assumptions about whether endDocument() will or will not be
114 * invoked when the parser has reported a fatalError() or thrown
115 * an exception.</strong></p>
116 *
117 * <p>This corresponds to the definition of "fatal error" in
118 * section 1.2 of the W3C XML 1.0 Recommendation. For example, a
119 * parser would use this callback to report the violation of a
120 * well-formedness constraint.</p>
121 *
122 * <p>The application must assume that the document is unusable
123 * after the parser has invoked this method, and should continue
124 * (if at all) only for the sake of collecting additional error
125 * messages: in fact, SAX parsers are free to stop reporting any
126 * other events once this method has been invoked.</p>
127 *
128 * @param exception The error information encapsulated in a
129 * SAX parse exception.
130 * @exception org.xml.sax.SAXException Any SAX exception, possibly
131 * wrapping another exception.
132 * @see org.xml.sax.SAXParseException
133 */
134 public abstract void fatalError (SAXParseException exception)
135 throws SAXException;
136
137 }
138
139 // end of ErrorHandler.java