1 /* 2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultUnionExpr.java,v 1.12 2005/04/03 01:30:10 elharo Exp $ 3 * $Revision: 1.12 $ 4 * $Date: 2005/04/03 01:30:10 $ 5 * 6 * ==================================================================== 7 * 8 * Copyright (C) 2000-2002 bob mcwhirter & James Strachan. 9 * All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions, and the following disclaimer. 17 * 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions, and the disclaimer that follows 20 * these conditions in the documentation and/or other materials 21 * provided with the distribution. 22 * 23 * 3. The name "Jaxen" must not be used to endorse or promote products 24 * derived from this software without prior written permission. For 25 * written permission, please contact license@jaxen.org. 26 * 27 * 4. Products derived from this software may not be called "Jaxen", nor 28 * may "Jaxen" appear in their name, without prior written permission 29 * from the Jaxen Project Management (pm@jaxen.org). 30 * 31 * In addition, we request (but do not require) that you include in the 32 * end-user documentation provided with the redistribution and/or in the 33 * software itself an acknowledgement equivalent to the following: 34 * "This product includes software developed by the 35 * Jaxen Project (http://www.jaxen.org/)." 36 * Alternatively, the acknowledgment may be graphical using the logos 37 * available at http://www.jaxen.org/ 38 * 39 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 40 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 41 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 42 * DISCLAIMED. IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT 43 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 45 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 46 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 47 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 48 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 49 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 50 * SUCH DAMAGE. 51 * 52 * ==================================================================== 53 * This software consists of voluntary contributions made by many 54 * individuals on behalf of the Jaxen Project and was originally 55 * created by bob mcwhirter <bob@werken.com> and 56 * James Strachan <jstrachan@apache.org>. For more information on the 57 * Jaxen Project, please see <http://www.jaxen.org/>. 58 * 59 * $Id: DefaultUnionExpr.java,v 1.12 2005/04/03 01:30:10 elharo Exp $ 60 */ 61 62 63 64 package org.jaxen.expr; 65 66 import java.util.ArrayList; 67 import java.util.Collections; 68 import java.util.HashSet; 69 import java.util.Iterator; 70 import java.util.List; 71 import java.util.Set; 72 import org.jaxen.Context; 73 import org.jaxen.JaxenException; 74 import org.jaxen.XPathSyntaxException; 75 76 public class DefaultUnionExpr extends DefaultBinaryExpr implements UnionExpr 77 { 78 public DefaultUnionExpr(Expr lhs, 79 Expr rhs) 80 { 81 super( lhs, 82 rhs ); 83 } 84 85 public String getOperator() 86 { 87 return "|"; 88 } 89 90 public String toString() 91 { 92 return "[(DefaultUnionExpr): " + getLHS() + ", " + getRHS() + "]"; 93 } 94 95 public Object evaluate(Context context) throws JaxenException 96 { 97 List results = new ArrayList(); 98 99 try { 100 List lhsResults = (List) getLHS().evaluate( context ); 101 List rhsResults = (List) getRHS().evaluate( context ); 102 103 Set unique = new HashSet(); 104 105 results.addAll( lhsResults ); 106 unique.addAll( lhsResults ); 107 108 Iterator rhsIter = rhsResults.iterator(); 109 110 while ( rhsIter.hasNext() ) 111 { 112 Object each = rhsIter.next(); 113 114 if ( ! unique.contains( each ) ) 115 { 116 results.add( each ); 117 unique.add( each ); 118 } 119 } 120 121 Collections.sort(results, new NodeComparator(context.getNavigator())); 122 123 return results; 124 } 125 catch (ClassCastException e) { 126 throw new XPathSyntaxException(this.getText(), context.getPosition(), "Unions are only allowed over node-sets"); 127 } 128 } 129 130 public void accept(Visitor visitor) 131 { 132 visitor.visit(this); 133 } 134 135 } 136