001: /*
002: * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
003: *
004: * This file is part of Resin(R) Open Source
005: *
006: * Each copy or derived work must preserve the copyright notice and this
007: * notice unmodified.
008: *
009: * Resin Open Source is free software; you can redistribute it and/or modify
010: * it under the terms of the GNU General Public License as published by
011: * the Free Software Foundation; either version 2 of the License, or
012: * (at your option) any later version.
013: *
014: * Resin Open Source is distributed in the hope that it will be useful,
015: * but WITHOUT ANY WARRANTY; without even the implied warranty of
016: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
017: * of NON-INFRINGEMENT. See the GNU General Public License for more
018: * details.
019: *
020: * You should have received a copy of the GNU General Public License
021: * along with Resin Open Source; if not, write to the
022: * Free SoftwareFoundation, Inc.
023: * 59 Temple Place, Suite 330
024: * Boston, MA 02111-1307 USA
025: *
026: * @author Scott Ferguson
027: */
028:
029: package com.caucho.xpath.pattern;
030:
031: import com.caucho.xpath.Env;
032: import com.caucho.xpath.ExprEnvironment;
033: import com.caucho.xpath.XPathException;
034:
035: import org.w3c.dom.Node;
036:
037: /**
038: * matches following siblings
039: */
040: public class FromNextSibling extends Axis {
041: public FromNextSibling(AbstractPattern parent) {
042: super (parent);
043:
044: if (parent == null)
045: throw new RuntimeException();
046: }
047:
048: /**
049: * matches if we can find a previous sibling that matches the parent.
050: *
051: * @param node the current node
052: * @param env the variable environment
053: *
054: * @return true if the pattern matches
055: */
056: public boolean match(Node node, ExprEnvironment env)
057: throws XPathException {
058: if (node == null)
059: return false;
060:
061: for (node = node.getPreviousSibling(); node != null; node = node
062: .getPreviousSibling()) {
063: if (_parent.match(node, env))
064: return true;
065: }
066:
067: return false;
068: }
069:
070: /**
071: * The count of nodes between the test-node and the axis.
072: *
073: * @param node the current node
074: * @param env the variable environment
075: */
076: public int position(Node node, Env env, AbstractPattern pattern)
077: throws XPathException {
078: int index = env.getPositionIndex();
079:
080: int count = 1;
081: while ((node = node.getPreviousSibling()) != null) {
082: if (_parent.match(node, env)) {
083: if (--index <= 0) {
084: // Test if there are more possible roots.
085: for (node = node.getPreviousSibling(); node != null; node = node
086: .getPreviousSibling()) {
087: if (_parent.match(node, env)) {
088: env.setMorePositions(true);
089: break;
090: }
091: }
092: return count;
093: }
094: }
095:
096: if (pattern.match(node, env))
097: count++;
098: }
099:
100: return count;
101: }
102:
103: /**
104: * Returns true if the pattern is strictly ascending.
105: */
106: public boolean isStrictlyAscending() {
107: if (_parent == null)
108: return true;
109: else
110: return _parent.isSingleSelect();
111: }
112:
113: /**
114: * Returns the first node in the selection order.
115: *
116: * @param node the current node
117: *
118: * @return the first node
119: */
120: public Node firstNode(Node node, ExprEnvironment env) {
121: return node.getNextSibling();
122: }
123:
124: /**
125: * Returns the next node in the selection order.
126: *
127: * @param node the current node
128: * @param lastNode the last node
129: *
130: * @return the next node
131: */
132: public Node nextNode(Node node, Node lastNode) {
133: return node.getNextSibling();
134: }
135:
136: public String toString() {
137: return getPrefix() + "following-sibling::";
138: }
139: }
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