/**
 * 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.lucene.gdata.storage;

import org.apache.lucene.gdata.server.registry.ServerComponent;

/**
 * An interface to define a central storage controller acting as a
 * <tt>Stroage</tt> Factory. The <tt>StroageController</tt> manages the
 * storage logic. Subclasses of {@link StorageController} can be registered as
 * {@link org.apache.lucene.gdata.server.registry.Component} in the
 * {@link org.apache.lucene.gdata.server.registry.GDataServerRegistry}. A
 * single instance of the contorller will be loaded and passed to clients via
 * the lookup service.
 * <p>
 * This instances, registered in the registry must be thread save as they are
 * shared between several clients
 * </p>
 * <p>
 * Each StroageController implementation must provide a super user
 * {@link org.apache.lucene.gdata.data.GDataAccount} with all
 * {@link org.apache.lucene.gdata.data.GDataAccount.AccountRole} set. This
 * account must have the defined name <i>administrator</i> and a default
 * password <i>password</i>. The password has to be updated by the server
 * administrator before production use.
 * To get the predefinded GDataAccount use {@link org.apache.lucene.gdata.data.GDataAccount#createAdminAccount()}
 * </p>
 *
 * 
 * @author Simon Willnauer
 * 
 */
public interface StorageController extends ServerComponent {
    /**
     * Destroys the controller - this method is called by the registry when the
     * context will be destroyed
     */
    public abstract void destroy();

    /**
     * Creates Storage instances to access the underlaying storage component
     * 
     * @return a storage instance
     * @throws StorageException -
     *             if the storage instance can not be created
     */
    public abstract Storage getStorage() throws StorageException;
    
    /**
     * Releases a new unique ID
     * @return - unique ID
     */
    public abstract String releaseId();
}