Frames | No Frames |
1: /* IdFunction.java -- 2: Copyright (C) 2004 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: package gnu.xml.xpath; 39: 40: import java.util.Collection; 41: import java.util.List; 42: import javax.xml.namespace.QName; 43: import org.w3c.dom.Node; 44: 45: /** 46: * The <code>id</code> function selects elements by their unique ID. 47: * When the argument to id is of type node-set, then the result is 48: * the union of the result of applying id to the string-value of each of the 49: * nodes in the argument node-set. When the argument to id is of any other 50: * type, the argument is converted to a string as if by a call to the string 51: * function; the string is split into a whitespace-separated list of tokens 52: * (whitespace is any sequence of characters matching the production S); the 53: * result is a node-set containing the elements in the same document as the 54: * context node that have a unique ID equal to any of the tokens in the 55: * list. 56: * 57: * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a> 58: */ 59: public final class IdFunction 60: extends Pattern 61: { 62: 63: final Expr arg; 64: 65: IdFunction(List args) 66: { 67: this((Expr) args.get(0)); 68: } 69: 70: public IdFunction(Expr arg) 71: { 72: this.arg = arg; 73: } 74: 75: public boolean matches(Node context) 76: { 77: Object ret = evaluate(context, 1, 1); 78: return !((Collection) ret).isEmpty(); 79: } 80: 81: public Object evaluate(Node context, int pos, int len) 82: { 83: Object val = arg.evaluate(context, pos, len); 84: return _id(context, val); 85: } 86: 87: public Expr clone(Object context) 88: { 89: return new IdFunction(arg.clone(context)); 90: } 91: 92: public boolean references(QName var) 93: { 94: return arg.references(var); 95: } 96: 97: public String toString() 98: { 99: return "id(" + arg + ")"; 100: } 101: 102: }