Commons JXPath example source code file (DOMNodeIterator.java)

This example Commons JXPath source code file (DOMNodeIterator.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons JXPath tags/keywords

dom, domnodeiterator, domnodeiterator, domnodepointer, node, node, nodeiterator, nodepointer, nodepointer, nodetest, nodetest

The Commons JXPath DOMNodeIterator.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.jxpath.ri.model.dom;

import org.apache.commons.jxpath.ri.compiler.NodeTest;
import org.apache.commons.jxpath.ri.model.NodeIterator;
import org.apache.commons.jxpath.ri.model.NodePointer;
import org.w3c.dom.Node;

/**
 * An iterator of children of a DOM Node.
 *
 * @author Dmitri Plotnikov
 * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
 */
public class DOMNodeIterator implements NodeIterator {
    private NodePointer parent;
    private NodeTest nodeTest;
    private Node node;
    private Node child = null;
    private boolean reverse;
    private int position = 0;

    /**
     * Create a new DOMNodeIterator.
     * @param parent parent pointer
     * @param nodeTest test
     * @param reverse whether to iterate in reverse
     * @param startWith starting pointer
     */
    public DOMNodeIterator(
        NodePointer parent,
        NodeTest nodeTest,
        boolean reverse,
        NodePointer startWith) {
        this.parent = parent;
        this.node = (Node) parent.getNode();
        if (startWith != null) {
            this.child = (Node) startWith.getNode();
        }
        this.nodeTest = nodeTest;
        this.reverse = reverse;
    }

    public NodePointer getNodePointer() {
        if (position == 0) {
            setPosition(1);
        }
        return child == null ? null : new DOMNodePointer(parent, child);
    }

    public int getPosition() {
        return position;
    }

    public boolean setPosition(int position) {
        while (this.position < position) {
            if (!next()) {
                return false;
            }
        }
        while (this.position > position) {
            if (!previous()) {
                return false;
            }
        }
        return true;
    }

    /**
     * Set the previous position.
     * @return whether valid
     */
    private boolean previous() {
        position--;
        if (!reverse) {
            if (position == 0) {
                child = null;
            }
            else if (child == null) {
                child = node.getLastChild();
            }
            else {
                child = child.getPreviousSibling();
            }
            while (child != null && !testChild()) {
                child = child.getPreviousSibling();
            }
        }
        else {
            child = child.getNextSibling();
            while (child != null && !testChild()) {
                child = child.getNextSibling();
            }
        }
        return child != null;
    }

    /**
     * Set the next position.
     * @return whether valid
     */
    private boolean next() {
        position++;
        if (!reverse) {
            if (position == 1) {
                if (child == null) {
                    child = node.getFirstChild();
                }
                else {
                    child = child.getNextSibling();
                }
            }
            else {
                child = child.getNextSibling();
            }
            while (child != null && !testChild()) {
                child = child.getNextSibling();
            }
        }
        else {
            if (position == 1) {
                if (child == null) {
                    child = node.getLastChild();
                }
                else {
                    child = child.getPreviousSibling();
                }
            }
            else {
                child = child.getPreviousSibling();
            }
            while (child != null && !testChild()) {
                child = child.getPreviousSibling();
            }
        }
        return child != null;
    }

    /**
     * Test child.
     * @return result of the test
     */
    private boolean testChild() {
        return DOMNodePointer.testNode(child, nodeTest);
    }
}