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.xml.XmlUtil;
032: import com.caucho.xpath.Env;
033: import com.caucho.xpath.ExprEnvironment;
034: import com.caucho.xpath.XPathException;
035:
036: import org.w3c.dom.Node;
037:
038: /**
039: * Matches any descendant.
040: */
041: public class FromDescendants extends Axis {
042: private boolean _self;
043:
044: public FromDescendants(AbstractPattern parent, boolean self) {
045: super (parent);
046:
047: _self = self;
048:
049: if (parent == null)
050: throw new RuntimeException();
051: }
052:
053: /**
054: * Matches the current node if it can find a parent node matching the
055: * parent pattern.
056: *
057: * @param node the node to test
058: * @param env the variable environment
059: *
060: * @return true if it matches.
061: */
062: public boolean match(Node node, ExprEnvironment env)
063: throws XPathException {
064: if (node == null)
065: return false;
066:
067: if (!_self)
068: node = node.getParentNode();
069:
070: for (; node != null; node = node.getParentNode()) {
071: if (_parent.match(node, env))
072: return true;
073: }
074:
075: return false;
076: }
077:
078: /**
079: * Counts matching nodes between the axis-context and the node
080: *
081: * @param node the starting node
082: * @param env the xpath environment
083: * @param pattern the axis match pattern
084: *
085: * @return the index of the position
086: */
087: public int position(Node node, Env env, AbstractPattern pattern)
088: throws XPathException {
089: int index = env.getPositionIndex();
090:
091: int pos = 0;
092:
093: Node parentNode = node;
094: Node ptr = node;
095:
096: for (; index >= 0; index--) {
097: for (; parentNode != null; parentNode = parentNode
098: .getParentNode()) {
099: if (_parent.match(parentNode, env))
100: break;
101: }
102:
103: for (; ptr != null; ptr = XmlUtil.getPrevious(ptr)) {
104: if (ptr == parentNode && !_self)
105: break;
106:
107: if (pattern.match(ptr, env))
108: pos++;
109:
110: if (ptr == parentNode)
111: break;
112: }
113:
114: if (index > 0 && parentNode != null) {
115: parentNode = parentNode.getParentNode();
116: if (_self)
117: ptr = XmlUtil.getPrevious(ptr);
118: } else
119: break;
120: }
121:
122: if (parentNode != null)
123: parentNode = parentNode.getParentNode();
124:
125: for (; parentNode != null; parentNode = parentNode
126: .getParentNode()) {
127: if (_parent.match(parentNode, env)) {
128: env.setMorePositions(true);
129: break;
130: }
131: }
132:
133: return pos;
134: }
135:
136: /**
137: * Counts the descendant nodes matching the pattern.
138: *
139: * @param node the starting node
140: * @param env the xpath environment
141: * @param pattern the axis match pattern
142: *
143: * @return the count of nodes
144: */
145: public int count(Node node, Env env, AbstractPattern pattern)
146: throws XPathException {
147: int index = env.getPositionIndex();
148:
149: Node axis;
150: if (_self)
151: axis = getAxisContext(node, env);
152: else
153: axis = getAxisContext(node.getParentNode(), env);
154:
155: for (; index > 0; index--)
156: axis = getAxisContext(axis.getParentNode(), env);
157:
158: if (getAxisContext(axis.getParentNode(), env) != null)
159: env.setMorePositions(true);
160:
161: int count = 0;
162: for (Node ptr = axis; ptr != null; ptr = XmlUtil.getNext(ptr)) {
163: if (pattern.match(ptr, env))
164: count++;
165: }
166:
167: return count;
168: }
169:
170: /**
171: * The axis context is any ancestor matching the parent pattern.
172: */
173: private Node getAxisContext(Node node, ExprEnvironment env)
174: throws XPathException {
175: for (; node != null; node = node.getParentNode()) {
176: if (_parent.match(node, env))
177: return node;
178: }
179:
180: return node;
181: }
182:
183: /**
184: * Returns true if the pattern is strictly ascending.
185: */
186: public boolean isStrictlyAscending() {
187: if (_parent == null)
188: return true;
189: else
190: return _parent.isSingleLevel();
191: }
192:
193: /**
194: * Returns the first node in the selection order.
195: *
196: * @param node the current node
197: *
198: * @return the first node
199: */
200: public Node firstNode(Node node, ExprEnvironment env) {
201: if (_self)
202: return node;
203: else
204: return node.getFirstChild();
205: }
206:
207: /**
208: * Returns the next node in the selection order.
209: *
210: * @param node the current node
211: * @param ndoe the last node
212: *
213: * @return the next node
214: */
215: public Node nextNode(Node node, Node lastNode) {
216: Node next = XmlUtil.getNext(node);
217:
218: return next == lastNode ? null : next;
219: }
220:
221: /**
222: * Returns the last node in the selection order.
223: *
224: * @param node the current node
225: *
226: * @return the last node
227: */
228: public Node lastNode(Node node) {
229: Node last = node;
230:
231: for (; last != null && last.getNextSibling() == null; last = last
232: .getParentNode()) {
233: }
234:
235: return last != null ? last.getNextSibling() : null;
236: }
237:
238: public String toString() {
239: if (_self)
240: return getPrefix() + "descendant-or-self::";
241: else
242: return getPrefix() + "descendant::";
243: }
244: }
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