1 /* UnionExpr.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.ArrayList; 41 import java.util.Collection; 42 import java.util.Collections; 43 import java.util.HashSet; 44 import java.util.List; 45 import java.util.Set; 46 import javax.xml.namespace.QName; 47 import org.w3c.dom.Node; 48 49 /** 50 * The union of two node-sets. 51 * 52 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a> 53 */ 54 public final class UnionExpr 55 extends Pattern 56 { 57 58 final Expr lhs; 59 final Expr rhs; 60 UnionExpr(Expr lhs, Expr rhs)61 public UnionExpr(Expr lhs, Expr rhs) 62 { 63 this.lhs = lhs; 64 this.rhs = rhs; 65 } 66 matches(Node context)67 public boolean matches(Node context) 68 { 69 if (lhs instanceof Pattern && rhs instanceof Pattern) 70 { 71 return ((Pattern) lhs).matches(context) || 72 ((Pattern) rhs).matches(context); 73 } 74 return false; 75 } 76 77 @Override evaluate(Node context, int pos, int len)78 public Object evaluate(Node context, int pos, int len) 79 { 80 Object left = lhs.evaluate(context, pos, len); 81 Object right = rhs.evaluate(context, pos, len); 82 List<Node> list; 83 if (left instanceof Collection && right instanceof Collection) 84 { 85 Set<Node> set = new HashSet<Node>(); 86 /* Suppression is safe as addAll will check the types 87 of the elements and throw a ClassCastException as necessary */ 88 @SuppressWarnings("unchecked") 89 Collection<Node> l = (Collection<Node>) left; 90 @SuppressWarnings("unchecked") 91 Collection<Node> r = (Collection<Node>) right; 92 set.addAll (l); 93 set.addAll (r); 94 list = new ArrayList<Node>(set); 95 Collections.sort(list, documentOrderComparator); 96 } 97 else 98 list = Collections.emptyList(); 99 return list; 100 } 101 clone(Object context)102 public Expr clone(Object context) 103 { 104 return new UnionExpr(lhs.clone(context), rhs.clone(context)); 105 } 106 references(QName var)107 public boolean references(QName var) 108 { 109 return (lhs.references(var) || rhs.references(var)); 110 } 111 toString()112 public String toString() 113 { 114 return lhs + " | " + rhs; 115 } 116 117 } 118