/*
 * 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 javax.jdo.metadata;

/**
 * This interface provides base level definitions for all metadata components.
 *
 * @version 3.0
 */
public interface Metadata {
    /**
     * Add a vendor extension to this metadata component.
     * 
     * @param vendor Identifier for the vendor
     * @param key The extension key
     * @param value Value for the extension
     * @return The ExtensionMetadata
     */
    ExtensionMetadata newExtensionMetadata(String vendor, String key, String value);

    /**
     * Number of extensions on this component.
     * 
     * @return Number of extensions
     */
    int getNumberOfExtensions();

    /**
     * Accessor for the defined extensions for this component
     * 
     * @return The extensions
     */
    ExtensionMetadata[] getExtensions();

    /**
     * Accessor for the parent metadata component.
     * 
     * @return The parent
     */
    Metadata getParent();
}
