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This module contains all API code for Apache Fluo. External dependencies should be limited. Any changes to public methods should be avoided. While the API module does not have compile time dependency on fluo-core, you must include fluo-core as a run-time dependency.
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/*
 * 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.fluo.api.client;

import org.apache.fluo.api.config.FluoConfiguration;

/**
 * Provides methods for initializing and administering a Fluo application.
 * 
 * @since 1.0.0
 */
public interface FluoAdmin extends AutoCloseable {

  /**
   * Specifies destructive Fluo initialization options that can not be set using
   * {@link FluoConfiguration}. The reason the options in this class are not supported in
   * {@link FluoConfiguration} is that allowing them to be saved in a config file may lead to
   * inadvertent clearing of a Fluo instance.
   *
   * @since 1.0.0
   */
  class InitializationOptions {

    private boolean clearZookeeper = false;
    private boolean clearTable = false;

    /**
     * Clears zookeeper root (if exists) specified by
     * {@value FluoConfiguration#CLIENT_ZOOKEEPER_CONNECT_PROP}. Default is false.
     */
    public InitializationOptions setClearZookeeper(boolean clearZookeeper) {
      this.clearZookeeper = clearZookeeper;
      return this;
    }

    public boolean getClearZookeeper() {
      return clearZookeeper;
    }

    /**
     * Clears accumulo table (if exists) specified by
     * {@value FluoConfiguration#ADMIN_ACCUMULO_TABLE_PROP}. Default is false.
     */
    public InitializationOptions setClearTable(boolean clearTable) {
      this.clearTable = clearTable;
      return this;
    }

    public boolean getClearTable() {
      return clearTable;
    }
  }

  /**
   * Exception that is thrown if Fluo application was already initialized. An application is already
   * initialized if a directory with same name as application exists at the chroot directory set by
   * the property fluo.client.zookeeper.connect. If this directory can be cleared, set
   * {@link InitializationOptions#setClearTable(boolean)} to true
   *
   * @since 1.0.0
   */
  class AlreadyInitializedException extends Exception {

    private static final long serialVersionUID = 1L;

    public AlreadyInitializedException(String msg) {
      super(msg);
    }

    public AlreadyInitializedException() {
      super();
    }
  }

  /**
   * Exception that is thrown if Accumulo table (set by fluo.admin.accumulo.table) exists during
   * initialization. If this table can be cleared, set
   * {@link InitializationOptions#setClearZookeeper(boolean)} to true
   *
   * @since 1.0.0
   */
  class TableExistsException extends Exception {

    private static final long serialVersionUID = 1L;

    public TableExistsException(String msg) {
      super(msg);
    }

    public TableExistsException() {
      super();
    }
  }

  /**
   * Initializes Fluo application and stores shared configuration in Zookeeper. Shared configuration
   * consists of properties with {@value org.apache.fluo.api.config.FluoConfiguration#APP_PREFIX},
   * {@value org.apache.fluo.api.config.FluoConfiguration#OBSERVER_PREFIX} and
   * {@value org.apache.fluo.api.config.FluoConfiguration#TRANSACTION_PREFIX} prefixes. Throws
   * {@link AlreadyInitializedException} if Fluo application was already initialized in Zookeeper.
   * If you want to initialize Zookeeper again, set
   * {@link InitializationOptions#setClearZookeeper(boolean)} to true. Throws
   * {@link TableExistsException} if Accumulo table exists. If you want to clear table, set
   * {@link InitializationOptions#setClearTable(boolean)} to true.
   */
  void initialize(InitializationOptions opts) throws AlreadyInitializedException,
      TableExistsException;

  /**
   * Updates shared configuration in Zookeeper. Shared configuration consists of properties with
   * {@value org.apache.fluo.api.config.FluoConfiguration#APP_PREFIX},
   * {@value org.apache.fluo.api.config.FluoConfiguration#OBSERVER_PREFIX} and
   * {@value org.apache.fluo.api.config.FluoConfiguration#TRANSACTION_PREFIX} prefixes. This method
   * is called if a user has previously called {@link #initialize(InitializationOptions)} but wants
   * changes to shared configuration updated in Zookeeper.
   * 
   * 
   * During this method Observers are reinitialized using configuration passed to FluoAdmin and not
   * existing shared configuration stored in zookeeper. So make sure all config needed by observers
   * is present.
   */
  void updateSharedConfig();

  @Override
  void close();
}