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 }