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Java > Open Source Codes > org > xml > sax > Locator


1 // SAX locator interface for document events.
2 // http://www.saxproject.org
3 // No warranty; no copyright -- use this as you will.
4 // $Id: Locator.java,v 1.1.24.1 2004/05/01 08:34:40 jsuttor Exp $
5
6 package org.xml.sax;
7
8
9 /**
10  * Interface for associating a SAX event with a document location.
11  *
12  * <blockquote>
13  * <em>This module, both source code and documentation, is in the
14  * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
15  * See <a HREF='http://www.saxproject.org'>http://www.saxproject.org</a>
16  * for further information.
17  * </blockquote>
18  *
19  * <p>If a SAX parser provides location information to the SAX
20  * application, it does so by implementing this interface and then
21  * passing an instance to the application using the content
22  * handler's {@link org.xml.sax.ContentHandler#setDocumentLocator
23  * setDocumentLocator} method. The application can use the
24  * object to obtain the location of any other SAX event
25  * in the XML source document.</p>
26  *
27  * <p>Note that the results returned by the object will be valid only
28  * during the scope of each callback method: the application
29  * will receive unpredictable results if it attempts to use the
30  * locator at any other time, or after parsing completes.</p>
31  *
32  * <p>SAX parsers are not required to supply a locator, but they are
33  * very strongly encouraged to do so. If the parser supplies a
34  * locator, it must do so before reporting any other document events.
35  * If no locator has been set by the time the application receives
36  * the {@link org.xml.sax.ContentHandler#startDocument startDocument}
37  * event, the application should assume that a locator is not
38  * available.</p>
39  *
40  * @since SAX 1.0
41  * @author David Megginson
42  * @version 2.0.1 (sax2r2)
43  * @see org.xml.sax.ContentHandler#setDocumentLocator
44  */
45 public interface Locator {
46     
47     
48     /**
49      * Return the public identifier for the current document event.
50      *
51      * <p>The return value is the public identifier of the document
52      * entity or of the external parsed entity in which the markup
53      * triggering the event appears.</p>
54      *
55      * @return A string containing the public identifier, or
56      * null if none is available.
57      * @see #getSystemId
58      */
59     public abstract String JavaDoc getPublicId ();
60     
61     
62     /**
63      * Return the system identifier for the current document event.
64      *
65      * <p>The return value is the system identifier of the document
66      * entity or of the external parsed entity in which the markup
67      * triggering the event appears.</p>
68      *
69      * <p>If the system identifier is a URL, the parser must resolve it
70      * fully before passing it to the application. For example, a file
71      * name must always be provided as a <em>file:...</em> URL, and other
72      * kinds of relative URI are also resolved against their bases.</p>
73      *
74      * @return A string containing the system identifier, or null
75      * if none is available.
76      * @see #getPublicId
77      */
78     public abstract String JavaDoc getSystemId ();
79     
80     
81     /**
82      * Return the line number where the current document event ends.
83      * Lines are delimited by line ends, which are defined in
84      * the XML specification.
85      *
86      * <p><strong>Warning:</strong> The return value from the method
87      * is intended only as an approximation for the sake of diagnostics;
88      * it is not intended to provide sufficient information
89      * to edit the character content of the original XML document.
90      * In some cases, these "line" numbers match what would be displayed
91      * as columns, and in others they may not match the source text
92      * due to internal entity expansion. </p>
93      *
94      * <p>The return value is an approximation of the line number
95      * in the document entity or external parsed entity where the
96      * markup triggering the event appears.</p>
97      *
98      * <p>If possible, the SAX driver should provide the line position
99      * of the first character after the text associated with the document
100      * event. The first line is line 1.</p>
101      *
102      * @return The line number, or -1 if none is available.
103      * @see #getColumnNumber
104      */
105     public abstract int getLineNumber ();
106     
107     
108     /**
109      * Return the column number where the current document event ends.
110      * This is one-based number of Java <code>char</code> values since
111      * the last line end.
112      *
113      * <p><strong>Warning:</strong> The return value from the method
114      * is intended only as an approximation for the sake of diagnostics;
115      * it is not intended to provide sufficient information
116      * to edit the character content of the original XML document.
117      * For example, when lines contain combining character sequences, wide
118      * characters, surrogate pairs, or bi-directional text, the value may
119      * not correspond to the column in a text editor's display. </p>
120      *
121      * <p>The return value is an approximation of the column number
122      * in the document entity or external parsed entity where the
123      * markup triggering the event appears.</p>
124      *
125      * <p>If possible, the SAX driver should provide the line position
126      * of the first character after the text associated with the document
127      * event. The first column in each line is column 1.</p>
128      *
129      * @return The column number, or -1 if none is available.
130      * @see #getLineNumber
131      */
132     public abstract int getColumnNumber ();
133     
134 }
135
136 // end of Locator.java
137
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