modules/api/src/main/java/io/fluo/api/client/FluoAdmin.java

/*
 * Copyright 2014 Fluo authors (see AUTHORS)
 * 
 * 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 io.fluo.api.client;

import io.fluo.api.config.FluoConfiguration;

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

  /**
   * Specifies Fluo initialization options such as clearing Zookeeper or existing Accumulo table.
   */
  class InitOpts {

    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 InitOpts 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 InitOpts 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 io.fluo.client.zookeeper.connect. If this directory can be cleared, set
   * {@link InitOpts#setClearTable(boolean)} to true
   */
  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 io.fluo.admin.accumulo.table) exists during
   * initialization. If this table can be cleared, set {@link InitOpts#setClearZookeeper(boolean)}
   * to true
   */
  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 io.fluo.api.config.FluoConfiguration#APP_PREFIX},
   * {@value io.fluo.api.config.FluoConfiguration#OBSERVER_PREFIX} and
   * {@value io.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 InitOpts#setClearZookeeper(boolean)} to
   * true. Throws {@link TableExistsException} if Accumulo table exists. If you want to clear table,
   * set {@link InitOpts#setClearTable(boolean)} to true.
   */
  void initialize(InitOpts opts) throws AlreadyInitializedException, TableExistsException;

  /**
   * Updates shared configuration in Zookeeper. Shared configuration consists of properties with
   * {@value io.fluo.api.config.FluoConfiguration#APP_PREFIX},
   * {@value io.fluo.api.config.FluoConfiguration#OBSERVER_PREFIX} and
   * {@value io.fluo.api.config.FluoConfiguration#TRANSACTION_PREFIX} prefixes. This method is
   * called if a user has previously called {@link #initialize(InitOpts)} but wants changes to
   * shared configuration updated in Zookeeper.
   * 
   * <p>
   * 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();
}