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.axes;
018    
019    import org.apache.commons.jxpath.Pointer;
020    import org.apache.commons.jxpath.ri.EvalContext;
021    import org.apache.commons.jxpath.ri.model.NodePointer;
022    
023    /**
024     * A single-set EvalContext that provides access to the current node of
025     * the parent context and nothing else.  It does not pass the iteration
026     * on to the parent context.
027     *
028     * @author Dmitri Plotnikov
029     * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
030     */
031    public class InitialContext extends EvalContext {
032        private boolean started = false;
033        private boolean collection;
034        private NodePointer nodePointer;
035    
036        /**
037         * Create a new InitialContext.
038         * @param parentContext parent context
039         */
040        public InitialContext(EvalContext parentContext) {
041            super(parentContext);
042            nodePointer =
043                (NodePointer) parentContext.getCurrentNodePointer().clone();
044            if (nodePointer != null) {
045                collection =
046                    (nodePointer.getIndex() == NodePointer.WHOLE_COLLECTION);
047            }
048        }
049    
050        public Pointer getSingleNodePointer() {
051            return nodePointer;
052        }
053    
054        public NodePointer getCurrentNodePointer() {
055            return nodePointer;
056        }
057    
058        public Object getValue() {
059            return nodePointer.getValue();
060        }
061    
062        public boolean nextNode() {
063            return setPosition(position + 1);
064        }
065    
066        public boolean setPosition(int position) {
067            this.position = position;
068            if (collection) {
069                if (position >= 1 && position <= nodePointer.getLength()) {
070                    nodePointer.setIndex(position - 1);
071                    return true;
072                }
073                return false;
074            }
075            return position == 1;
076        }
077    
078        public boolean nextSet() {
079            if (started) {
080                return false;
081            }
082            started = true;
083            return true;
084        }
085    }