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 */
017package org.apache.commons.jxpath.ri.compiler;
018
019import org.apache.commons.jxpath.ri.EvalContext;
020import 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 13:46:46 -0400 (Fri, 02 May 2008) $
027 */
028public 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}