    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.ri.Compiler;
    020    import org.apache.commons.jxpath.ri.EvalContext;
    021    import org.apache.commons.jxpath.ri.QName;
    022    import org.apache.commons.jxpath.ri.compiler.NodeNameTest;
    023    import org.apache.commons.jxpath.ri.compiler.NodeTest;
    024    import org.apache.commons.jxpath.ri.compiler.NodeTypeTest;
    025    import org.apache.commons.jxpath.ri.model.NodeIterator;
    026    import org.apache.commons.jxpath.ri.model.NodePointer;
    027
    028    /**
    029     * EvalContext that walks the "attribute::" axis.
    030     *
    031     * @author Dmitri Plotnikov
    032     * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
    033     */
    034    public class AttributeContext extends EvalContext {
    035        private static final QName WILDCARD = new QName(null, "*");
    036
    037        private NodeTest nodeTest;
    038        private boolean setStarted = false;
    039        private NodeIterator iterator;
    040        private NodePointer currentNodePointer;
    041
    042        /**
    043         * Create a new AttributeContext.
    044         * @param parentContext represents the previous step on the path
    045         * @param nodeTest is the name of the attribute we are looking for
    046         */
    047        public AttributeContext(EvalContext parentContext, NodeTest nodeTest) {
    048            super(parentContext);
    049            this.nodeTest = nodeTest;
    050        }
    051
    052        public NodePointer getCurrentNodePointer() {
    053            return currentNodePointer;
    054        }
    055
    056        public void reset() {
    057            setStarted = false;
    058            iterator = null;
    059            super.reset();
    060        }
    061
    062        public boolean setPosition(int position) {
    063            if (position < getCurrentPosition()) {
    064                reset();
    065            }
    066
    067            while (getCurrentPosition() < position) {
    068                if (!nextNode()) {
    069                    return false;
    070                }
    071            }
    072            return true;
    073        }
    074
    075        public boolean nextNode() {
    076            super.setPosition(getCurrentPosition() + 1);
    077            if (!setStarted) {
    078                setStarted = true;
    079                QName name;
    080                if (nodeTest instanceof NodeNameTest) {
    081                    name = ((NodeNameTest) nodeTest).getNodeName();
    082                }
    083                else {
    084                    if (nodeTest instanceof NodeTypeTest
    085                            && ((NodeTypeTest) nodeTest).getNodeType() == Compiler.NODE_TYPE_NODE) {
    086                        name = WILDCARD;
    087                    }
    088                    else {
    089                        iterator = null;
    090                        return false;
    091                    }
    092                }
    093                iterator = parentContext.getCurrentNodePointer().attributeIterator(
    094                        name);
    095            }
    096            if (iterator == null) {
    097                return false;
    098            }
    099            if (!iterator.setPosition(iterator.getPosition() + 1)) {
    100                return false;
    101            }
    102            currentNodePointer = iterator.getNodePointer();
    103            return true;
    104        }
    105    }