001 /*
002 * Copyright (c) 2004 World Wide Web Consortium,
003 *
004 * (Massachusetts Institute of Technology, European Research Consortium for
005 * Informatics and Mathematics, Keio University). All Rights Reserved. This
006 * work is distributed under the W3C(r) Software License [1] in the hope that
007 * it will be useful, but WITHOUT ANY WARRANTY; without even the implied
008 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
009 *
010 * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231
011 */
012
013 package org.w3c.dom.xpath;
014
015 import org.w3c.dom.Node;
016 import org.w3c.dom.DOMException;
017
018 /**
019 * The <code>XPathResult</code> interface represents the result of the
020 * evaluation of an XPath 1.0 expression within the context of a particular
021 * node. Since evaluation of an XPath expression can result in various
022 * result types, this object makes it possible to discover and manipulate
023 * the type and value of the result.
024 * <p>See also the <a href='http://www.w3.org/TR/2004/NOTE-DOM-Level-3-XPath-20040226'>Document Object Model (DOM) Level 3 XPath Specification</a>.
025 */
026 public interface XPathResult {
027 // XPathResultType
028 /**
029 * This code does not represent a specific type. An evaluation of an XPath
030 * expression will never produce this type. If this type is requested,
031 * then the evaluation returns whatever type naturally results from
032 * evaluation of the expression.
033 * <br>If the natural result is a node set when <code>ANY_TYPE</code> was
034 * requested, then <code>UNORDERED_NODE_ITERATOR_TYPE</code> is always
035 * the resulting type. Any other representation of a node set must be
036 * explicitly requested.
037 */
038 public static final short ANY_TYPE = 0;
039 /**
040 * The result is a <a href='http://www.w3.org/TR/1999/REC-xpath-19991116#numbers'>number</a> as defined by [<a href='http://www.w3.org/TR/1999/REC-xpath-19991116'>XPath 1.0</a>].
041 * Document modification does not invalidate the number, but may mean
042 * that reevaluation would not yield the same number.
043 */
044 public static final short NUMBER_TYPE = 1;
045 /**
046 * The result is a <a href='http://www.w3.org/TR/1999/REC-xpath-19991116#strings'>string</a> as defined by [<a href='http://www.w3.org/TR/1999/REC-xpath-19991116'>XPath 1.0</a>].
047 * Document modification does not invalidate the string, but may mean
048 * that the string no longer corresponds to the current document.
049 */
050 public static final short STRING_TYPE = 2;
051 /**
052 * The result is a <a href='http://www.w3.org/TR/1999/REC-xpath-19991116#booleans'>boolean</a> as defined by [<a href='http://www.w3.org/TR/1999/REC-xpath-19991116'>XPath 1.0</a>].
053 * Document modification does not invalidate the boolean, but may mean
054 * that reevaluation would not yield the same boolean.
055 */
056 public static final short BOOLEAN_TYPE = 3;
057 /**
058 * The result is a <a href='http://www.w3.org/TR/1999/REC-xpath-19991116#node-sets'>node set</a> as defined by [<a href='http://www.w3.org/TR/1999/REC-xpath-19991116'>XPath 1.0</a>] that
059 * will be accessed iteratively, which may not produce nodes in a
060 * particular order. Document modification invalidates the iteration.
061 * <br>This is the default type returned if the result is a node set and
062 * <code>ANY_TYPE</code> is requested.
063 */
064 public static final short UNORDERED_NODE_ITERATOR_TYPE = 4;
065 /**
066 * The result is a node set as defined by [<a href='http://www.w3.org/TR/1999/REC-xpath-19991116'>XPath 1.0</a>] that
067 * will be accessed iteratively, which will produce document-ordered
068 * nodes. Document modification invalidates the iteration.
069 */
070 public static final short ORDERED_NODE_ITERATOR_TYPE = 5;
071 /**
072 * The result is a <a href='http://www.w3.org/TR/1999/REC-xpath-19991116#node-sets'>node set</a> as defined by [<a href='http://www.w3.org/TR/1999/REC-xpath-19991116'>XPath 1.0</a>] that
073 * will be accessed as a snapshot list of nodes that may not be in a
074 * particular order. Document modification does not invalidate the
075 * snapshot but may mean that reevaluation would not yield the same
076 * snapshot and nodes in the snapshot may have been altered, moved, or
077 * removed from the document.
078 */
079 public static final short UNORDERED_NODE_SNAPSHOT_TYPE = 6;
080 /**
081 * The result is a <a href='http://www.w3.org/TR/1999/REC-xpath-19991116#node-sets'>node set</a> as defined by [<a href='http://www.w3.org/TR/1999/REC-xpath-19991116'>XPath 1.0</a>] that
082 * will be accessed as a snapshot list of nodes that will be in original
083 * document order. Document modification does not invalidate the
084 * snapshot but may mean that reevaluation would not yield the same
085 * snapshot and nodes in the snapshot may have been altered, moved, or
086 * removed from the document.
087 */
088 public static final short ORDERED_NODE_SNAPSHOT_TYPE = 7;
089 /**
090 * The result is a <a href='http://www.w3.org/TR/1999/REC-xpath-19991116#node-sets'>node set</a> as defined by [<a href='http://www.w3.org/TR/1999/REC-xpath-19991116'>XPath 1.0</a>] and
091 * will be accessed as a single node, which may be <code>null</code>if
092 * the node set is empty. Document modification does not invalidate the
093 * node, but may mean that the result node no longer corresponds to the
094 * current document. This is a convenience that permits optimization
095 * since the implementation can stop once any node in the resulting set
096 * has been found.
097 * <br>If there is more than one node in the actual result, the single
098 * node returned might not be the first in document order.
099 */
100 public static final short ANY_UNORDERED_NODE_TYPE = 8;
101 /**
102 * The result is a <a href='http://www.w3.org/TR/1999/REC-xpath-19991116#node-sets'>node set</a> as defined by [<a href='http://www.w3.org/TR/1999/REC-xpath-19991116'>XPath 1.0</a>] and
103 * will be accessed as a single node, which may be <code>null</code> if
104 * the node set is empty. Document modification does not invalidate the
105 * node, but may mean that the result node no longer corresponds to the
106 * current document. This is a convenience that permits optimization
107 * since the implementation can stop once the first node in document
108 * order of the resulting set has been found.
109 * <br>If there are more than one node in the actual result, the single
110 * node returned will be the first in document order.
111 */
112 public static final short FIRST_ORDERED_NODE_TYPE = 9;
113
114 /**
115 * A code representing the type of this result, as defined by the type
116 * constants.
117 */
118 public short getResultType();
119
120 /**
121 * The value of this number result. If the native double type of the DOM
122 * binding does not directly support the exact IEEE 754 result of the
123 * XPath expression, then it is up to the definition of the binding to
124 * specify how the XPath number is converted to the native binding
125 * number.
126 * @exception XPathException
127 * TYPE_ERR: raised if <code>resultType</code> is not
128 * <code>NUMBER_TYPE</code>.
129 */
130 public double getNumberValue()
131 throws XPathException;
132
133 /**
134 * The value of this string result.
135 * @exception XPathException
136 * TYPE_ERR: raised if <code>resultType</code> is not
137 * <code>STRING_TYPE</code>.
138 */
139 public String getStringValue()
140 throws XPathException;
141
142 /**
143 * The value of this boolean result.
144 * @exception XPathException
145 * TYPE_ERR: raised if <code>resultType</code> is not
146 * <code>BOOLEAN_TYPE</code>.
147 */
148 public boolean getBooleanValue()
149 throws XPathException;
150
151 /**
152 * The value of this single node result, which may be <code>null</code>.
153 * @exception XPathException
154 * TYPE_ERR: raised if <code>resultType</code> is not
155 * <code>ANY_UNORDERED_NODE_TYPE</code> or
156 * <code>FIRST_ORDERED_NODE_TYPE</code>.
157 */
158 public Node getSingleNodeValue()
159 throws XPathException;
160
161 /**
162 * Signifies that the iterator has become invalid. True if
163 * <code>resultType</code> is <code>UNORDERED_NODE_ITERATOR_TYPE</code>
164 * or <code>ORDERED_NODE_ITERATOR_TYPE</code> and the document has been
165 * modified since this result was returned.
166 */
167 public boolean getInvalidIteratorState();
168
169 /**
170 * The number of nodes in the result snapshot. Valid values for
171 * snapshotItem indices are <code>0</code> to
172 * <code>snapshotLength-1</code> inclusive.
173 * @exception XPathException
174 * TYPE_ERR: raised if <code>resultType</code> is not
175 * <code>UNORDERED_NODE_SNAPSHOT_TYPE</code> or
176 * <code>ORDERED_NODE_SNAPSHOT_TYPE</code>.
177 */
178 public int getSnapshotLength()
179 throws XPathException;
180
181 /**
182 * Iterates and returns the next node from the node set or
183 * <code>null</code>if there are no more nodes.
184 * @return Returns the next node.
185 * @exception XPathException
186 * TYPE_ERR: raised if <code>resultType</code> is not
187 * <code>UNORDERED_NODE_ITERATOR_TYPE</code> or
188 * <code>ORDERED_NODE_ITERATOR_TYPE</code>.
189 * @exception DOMException
190 * INVALID_STATE_ERR: The document has been mutated since the result was
191 * returned.
192 */
193 public Node iterateNext()
194 throws XPathException, DOMException;
195
196 /**
197 * Returns the <code>index</code>th item in the snapshot collection. If
198 * <code>index</code> is greater than or equal to the number of nodes in
199 * the list, this method returns <code>null</code>. Unlike the iterator
200 * result, the snapshot does not become invalid, but may not correspond
201 * to the current document if it is mutated.
202 * @param index Index into the snapshot collection.
203 * @return The node at the <code>index</code>th position in the
204 * <code>NodeList</code>, or <code>null</code> if that is not a valid
205 * index.
206 * @exception XPathException
207 * TYPE_ERR: raised if <code>resultType</code> is not
208 * <code>UNORDERED_NODE_SNAPSHOT_TYPE</code> or
209 * <code>ORDERED_NODE_SNAPSHOT_TYPE</code>.
210 */
211 public Node snapshotItem(int index)
212 throws XPathException;
213
214 }