001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.jxpath.ri.compiler;
018    
019    import org.apache.commons.jxpath.ri.EvalContext;
020    import org.apache.commons.jxpath.ri.axes.UnionContext;
021    
022    /**
023     * Implementation of {@link Expression} for the operation "|".
024     *
025     * @author Dmitri Plotnikov
026     * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
027     */
028    public class CoreOperationUnion extends CoreOperation {
029    
030        /**
031         * Create a new CoreOperationUnion.
032         * @param args Expression[]
033         */
034        public CoreOperationUnion(Expression[] args) {
035            super(args);
036        }
037    
038        public Object computeValue(EvalContext context) {
039            EvalContext[] argCtxs = new EvalContext[args.length];
040            for (int i = 0; i < args.length; i++) {
041                Object value = args[i].compute(context);
042                if (value instanceof EvalContext) {
043                    argCtxs[i] = (EvalContext) value;
044                }
045                else {
046                    argCtxs[i] = context.getRootContext().getConstantContext(value);
047                }
048            }
049            return new UnionContext(context.getRootContext(), argCtxs);
050        }
051    
052        protected int getPrecedence() {
053            return UNION_PRECEDENCE;
054        }
055    
056        protected boolean isSymmetric() {
057            return true;
058        }
059    
060        public String getSymbol() {
061            return "|";
062        }
063    }