1 /* NumberFunction.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.List; 41 import javax.xml.namespace.QName; 42 import org.w3c.dom.Node; 43 44 /** 45 * The <code>number</code> function converts its argument to a number as 46 * follows: 47 * <ul> 48 * <li>a string that consists of optional whitespace followed by an optional 49 * minus sign followed by a Number followed by whitespace is converted to 50 * the IEEE 754 number that is nearest (according to the IEEE 754 51 * round-to-nearest rule) to the mathematical value represented by the 52 * string; any other string is converted to NaN</li> 53 * <li>boolean true is converted to 1; boolean false is converted to 0</li> 54 * <li>a node-set is first converted to a string as if by a call to the 55 * string function and then converted in the same way as a string 56 * argument</li> 57 * <li>an object of a type other than the four basic types is converted to a 58 * number in a way that is dependent on that type</li> 59 * </ul> 60 * If the argument is omitted, it defaults to a node-set with the context 61 * node as its only member. 62 * 63 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a> 64 */ 65 final class NumberFunction 66 extends Expr 67 { 68 69 final Expr arg; 70 NumberFunction(List<Expr> args)71 NumberFunction(List<Expr> args) 72 { 73 this(args.size() > 0 ? args.get(0) : null); 74 } 75 NumberFunction(Expr arg)76 NumberFunction(Expr arg) 77 { 78 this.arg = arg; 79 } 80 81 @Override evaluate(Node context, int pos, int len)82 public Object evaluate(Node context, int pos, int len) 83 { 84 Object val = (arg == null) ? null : arg.evaluate(context, pos, len); 85 return new Double(_number(context, val)); 86 } 87 clone(Object context)88 public Expr clone(Object context) 89 { 90 return new NumberFunction(arg.clone(context)); 91 } 92 references(QName var)93 public boolean references(QName var) 94 { 95 return arg.references(var); 96 } 97 toString()98 public String toString() 99 { 100 return "number(" + arg + ")"; 101 } 102 103 } 104