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1
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
137 |
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