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
018package org.apache.commons.jxpath.ri.axes;
019
020import org.apache.commons.jxpath.Pointer;
021import org.apache.commons.jxpath.ri.EvalContext;
022import org.apache.commons.jxpath.ri.compiler.NodeTest;
023import org.apache.commons.jxpath.ri.model.NodePointer;
024
025/**
026 * EvalContext that returns the current node from the parent context if the test succeeds.
027 */
028public class SelfContext extends EvalContext {
029
030    private final NodeTest nodeTest;
031    private boolean startedSet;
032    private NodePointer nodePointer;
033
034    /**
035     * Constructs a new SelfContext.
036     *
037     * @param parentContext EvalContext
038     * @param nodeTest      guard
039     */
040    public SelfContext(final EvalContext parentContext, final NodeTest nodeTest) {
041        super(parentContext);
042        this.nodeTest = nodeTest;
043    }
044
045    @Override
046    public NodePointer getCurrentNodePointer() {
047        if (position == 0 && !setPosition(1)) {
048            return null;
049        }
050        return nodePointer;
051    }
052
053    @Override
054    public Pointer getSingleNodePointer() {
055        return parentContext.getSingleNodePointer();
056    }
057
058    @Override
059    public boolean nextNode() {
060        return setPosition(getCurrentPosition() + 1);
061    }
062
063    @Override
064    public void reset() {
065        super.reset();
066        startedSet = false;
067    }
068
069    @Override
070    public boolean setPosition(final int position) {
071        if (position != 1) {
072            return false;
073        }
074        super.setPosition(position);
075        if (!startedSet) {
076            startedSet = true;
077            nodePointer = parentContext.getCurrentNodePointer();
078        }
079        if (nodePointer == null) {
080            return false;
081        }
082        return nodeTest == null || nodePointer.testNode(nodeTest);
083    }
084}