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.compiler.NodeTest;
022    import org.apache.commons.jxpath.ri.model.NodePointer;
023    
024    /**
025     * EvalContext that returns the current node from the parent context if the
026     * test succeeds.
027     *
028     * @author Dmitri Plotnikov
029     * @version $Revision: 670727 $ $Date: 2008-06-23 15:10:38 -0500 (Mon, 23 Jun 2008) $
030     */
031    public class SelfContext extends EvalContext {
032        private NodeTest nodeTest;
033        private boolean startedSet = false;
034        private NodePointer nodePointer;
035    
036        /**
037         * Create a new SelfContext.
038         * @param parentContext EvalContext
039         * @param nodeTest guard
040         */
041        public SelfContext(EvalContext parentContext, NodeTest nodeTest) {
042            super(parentContext);
043            this.nodeTest = nodeTest;
044        }
045    
046        public Pointer getSingleNodePointer() {
047            return parentContext.getSingleNodePointer();
048        }
049    
050        public NodePointer getCurrentNodePointer() {
051            if (position == 0 && !setPosition(1)) {
052                return null;
053            }
054            return nodePointer;
055        }
056    
057        public boolean nextNode() {
058            return setPosition(getCurrentPosition() + 1);
059        }
060    
061        public void reset() {
062            super.reset();
063            startedSet = false;
064        }
065    
066        public boolean setPosition(int position) {
067            if (position != 1) {
068                return false;
069            }
070            super.setPosition(position);
071            if (!startedSet) {
072                startedSet = true;
073                nodePointer = (NodePointer) parentContext.getCurrentNodePointer();
074            }
075    
076            if (nodePointer == null) {
077                return false;
078            }
079    
080            return nodeTest == null || nodePointer.testNode(nodeTest);
081        }
082    }