/*
 * Copyright 2004-2008 Andy Clark, Marc Guillemot
 * 
 * Licensed 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 com.googlecode.html;

import org.apache.xerces.xni.Augmentations;

import java.util.Enumeration;
import java.util.Hashtable;

/**
 * This class is here to overcome the XNI changes to the <code>Augmentations</code> interface. In
 * early versions of XNI, the augmentations interface contained a <code>clear()</code> method to
 * remove all of the items from the augmentations instance. A later version of XNI changed this
 * method to <code>removeAllItems()</code>. Therefore, this class extends the augmentations
 * interface and explicitly implements both of these methods.
 * <p>
 * <strong>Note:</strong> This code is inspired by performance enhancements submitted by Marc-André
 * Morissette.
 *
 * @author Andy Clark
 */
public class HTMLAugmentations implements Augmentations {

    //
    // Data
    //

    /**
     * Augmentation items.
     */
    protected final Hashtable fItems = new Hashtable();

    //
    // Public methods
    //
    public HTMLAugmentations() {
        // nothing
    }

    /**
     * Copy constructor
     *
     * @param augs the object to copy
     */
    HTMLAugmentations(final Augmentations augs) {
        for (final Enumeration keys = augs.keys(); keys.hasMoreElements(); ) {
            final String key = (String) keys.nextElement();
            Object value = augs.getItem(key);
            if (value instanceof HTMLScanner.LocationItem) {
                value = new HTMLScanner.LocationItem((HTMLScanner.LocationItem) value);
            }
            fItems.put(key, value);
        }
    }

    // since Xerces 2.3.0

    /**
     * Removes all of the elements in this augmentations object.
     */
    public void clear() {
        fItems.clear();
    } // clear()

    // from Xerces 2.0.0 (beta4) until 2.3.0

    /**
     * Get information identified by a key from the Augmentations structure.
     *
     * @param key Identifier, can't be <code>null</code>
     * @return The value to which the key is mapped in the Augmentations structure; <code>null</code>
     * if the key is not mapped to any value.
     */
    public Object getItem(String key) {
        return fItems.get(key);
    } // getItem(String):Object

    //
    // Augmentations methods
    //

    /**
     * Returns an enumeration of the keys in the Augmentations structure.
     */
    public Enumeration keys() {
        return fItems.keys();
    } // keys():Enumeration

    /**
     * Add additional information identified by a key to the Augmentations structure.
     *
     * @param key  Identifier, can't be <code>null</code>
     * @param item Additional information
     * @return The previous value of the specified key in the Augmentations structure, or
     * <code>null</code> if it did not have one.
     */
    public Object putItem(String key, Object item) {
        return fItems.put(key, item);
    } // putItem(String, Object):Object

    /**
     * Removes all of the elements in this augmentations object.
     */
    public void removeAllItems() {
        fItems.clear();
    } // removeAllItems()

    /**
     * Remove additional info from the Augmentations structure
     *
     * @param key Identifier, can't be <code>null</code>
     * @return The previous value of the specified key in the Augmentations structure, or
     * <code>null</code> if it did not have one.
     */
    public Object removeItem(String key) {
        return fItems.remove(key);
    } // removeItem(String):Object

} // class HTMLAugmentations