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/*
// Licensed to Julian Hyde under one or more contributor license
// agreements. See the NOTICE file distributed with this work for
// additional information regarding copyright ownership.
//
// Julian Hyde 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.eigenbase.xom.wrappers;

import org.eigenbase.xom.*;
import org.w3c.dom.CharacterData;
import org.w3c.dom.*;

/**
 * This implementation of DOMWrapper wraps any w3c DOM-compliant java
 * XML Parser.
 */
public class W3CDOMWrapper implements DOMWrapper {

    final Node node;
    private final Locator locator;

    /**
     * W3CDOMWrapper parses XML based on a Node.  The Node may be either an
     * Element or some form of text node.
     *
     * @param node DOM Node
     * @param locator Callback to find location of node. May be null.
     */
    public W3CDOMWrapper(Node node, Locator locator)
    {
        this.node = node;
        this.locator = locator;
    }

    /**
     * Map the Node's type to DOMWrapper's simplified concept of type.
     */
    public int getType()
    {
        int nodeType = node.getNodeType();
        switch (nodeType) {
        case Node.ELEMENT_NODE:
            return ELEMENT;
        case Node.COMMENT_NODE:
            return COMMENT;
        case Node.CDATA_SECTION_NODE:
            return CDATA;
        case Node.TEXT_NODE:
            return FREETEXT;
        default:
            return UNKNOWN;
        }
    }

    /**
     * Retrieve the tag name directly.  Return null immediately if not an
     * element.
     */
    public String getTagName()
    {
        if (getType() != ELEMENT) {
            return null;
        }
        return ((Element)node).getTagName();
    }

    /**
     * Return the attribute.  Return null if the attribute isn't defined,
     * or if not an element.  This behavior differs from the underlying DOM,
     * which returns an empty string for undefined attributes.
     */
    public String getAttribute(String attrName)
    {
        if (getType() != ELEMENT) {
            return null;
        }
        String attrVal = ((Element)node).getAttribute(attrName);
        if (attrVal == null || attrVal.length() == 0) {
            return null;
        } else {
            return attrVal;
        }
    }

    // implement DOMWrapper
    public String[] getAttributeNames()
    {
        NamedNodeMap map = node.getAttributes();
        int count = map.getLength();
        String[] attributeNames = new String[count];
        for (int i = 0; i < count; i++) {
            attributeNames[i] = map.item(i).getLocalName();
        }
        return attributeNames;
    }

    /**
     * Recursively unwrap and create the contained text.  If the node is a
     * comment, return the comment text; but ignore comments inside elements.
     */
    public String getText()
    {
        if (node instanceof Comment) {
            return ((Comment)node).getData();
        } else {
            StringBuffer sbuf = new StringBuffer();
            appendNodeText(node, sbuf);
            return sbuf.toString();
        }
    }

    // implement DOMWrapper
    public String toXML()
    {
        boolean onlyElements = false;
        return XOMUtil.wrapperToXml(this, onlyElements);
    }

    /**
     * Helper to collect all Text nodes into a buffer.
     */
    private static void appendNodeText(Node node, StringBuffer sbuf)
    {
        if (node instanceof Comment) {
            // ignore it
        } else if (node instanceof CharacterData) {
            // Text
            sbuf.append(((CharacterData)node).getData());
        } else if (node instanceof Element) {
            NodeList nodeList = node.getChildNodes();
            for (int i = 0; i < nodeList.getLength(); i++) {
                appendNodeText(nodeList.item(i), sbuf);
            }
        }
    }

    /**
     * Retrieve all children, and build an array of W3CDOMWrappers around
     * each child that is of TEXT or ELEMENT type to return.
     */
    public DOMWrapper[] getChildren()
    {
        if (getType() != ELEMENT) {
            return new DOMWrapper[0];
        }
        NodeList nodeList = node.getChildNodes();

        // Count the elements that are TEXT or ELEMENTs.
        int count = 0;
        for (int i = 0; i < nodeList.getLength(); i++) {
            Node nextNode = nodeList.item(i);
            if (nextNode instanceof Element || nextNode instanceof Text) {
                count++;
            }
        }

        // Create and populate the array
        DOMWrapper[] ret = new DOMWrapper[count];
        count = 0;
        for (int i = 0; i < nodeList.getLength(); i++) {
            Node nextNode = nodeList.item(i);
            if (nextNode instanceof Element || nextNode instanceof Text) {
                ret[count++] = new W3CDOMWrapper(nextNode, locator);
            }
        }

        // Done.
        return ret;
    }

    /**
     * Retrieve all children, and build an array of W3CDOMWrappers around
     * each ELEMENT child.
     */
    public DOMWrapper[] getElementChildren()
    {
        if (getType() != ELEMENT) {
            return new DOMWrapper[0];
        }
        NodeList nodeList = node.getChildNodes();

        // Count the elements that are TEXT or ELEMENTs.
        int count = 0;
        for (int i = 0; i < nodeList.getLength(); i++) {
            Node nextNode = nodeList.item(i);
            if (nextNode instanceof Element) {
                count++;
            }
        }

        // Create and populate the array
        DOMWrapper[] ret = new DOMWrapper[count];
        count = 0;
        for (int i = 0; i < nodeList.getLength(); i++) {
            Node nextNode = nodeList.item(i);
            if (nextNode instanceof Element) {
                ret[count++] = new W3CDOMWrapper(nextNode, locator);
            }
        }

        // Done.
        return ret;
    }

    public Location getLocation()
    {
        return locator.getLocation(this);
    }
}

// End W3CDOMWrapper.java