    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    }