/****************************************************************
 * 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.james.onami.lifecycle;

import java.lang.annotation.Annotation;

/**
 * A Stager is a mini-container that stages resources
 * invoking {@link Stageable#stage(StageHandler)}.
 * <p/>
 * Order of disposal is specified by the concrete implementation of this
 * interface via {@link org.apache.onami.lifecycle.core.DefaultStager.Order}.
 * <p/>
 * Implementations must be thread-safe because registration can be done from
 * any thread.
 */
public interface Stager<A extends Annotation> {

    /**
     * Register a {@link Stageable} to stage resources.
     *
     * @param stageable object to be invoked to stage resources.
     */
    void register(Stageable stageable);

    /**
     * Stages resources invoking {@link Stageable#stage(StageHandler)}.
     */
    void stage();

    /**
     * Stages resources invoking {@link Stageable#stage(StageHandler)}.
     *
     * @param stageHandler the {@link StageHandler} instance that tracks progresses.
     * @since 0.2.0
     */
    void stage(StageHandler stageHandler);

    /**
     * Returns the annotation that represents this stage.
     *
     * @return stage annotation.
     */
    Class<A> getStage();

}
