PrematureRepositoryManager.java

/*
 * Copyright 2012 NGDATA nv
 *
 * 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 org.lilyproject.util.repo;

import org.lilyproject.repository.api.RepositoryManager;

/**
 * A {@code RepositoryManager} implementation on which all calls will block indefinitely until
 * the {@link #setRepositoryManager(RepositoryManager)} method has been called to set a repository
 * manager to which the calls will be delegated.
 *
 * This provides a solution for circular dependencies in the Lily-server startup scenario.
 * E.g. some services need to be started before the repository manager because they must be active
 * from the moment the first repository operation is executed, but they depend themselves
 * also on the RepositoryManager.
 *
 * <p>In some cases, the RepositoryManager can provide a reference to itself when calling these
 * services, but in some cases this is not possible, and there this Repository object
 * helps. It will <b>block</b> calls until the RepositoryManager is available. The
 * RepositoryManager is made available by calling the setRepositoryManager method.
 */
public interface PrematureRepositoryManager extends RepositoryManager {
    void setRepositoryManager(RepositoryManager repository);
}