/**
 * 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.hadoop.hbase.client;

import java.io.Closeable;
import java.util.concurrent.ExecutorService;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.classification.InterfaceAudience;

/**
 * The asynchronous version of Connection.
 */
@InterfaceAudience.Public
public interface AsyncConnection extends Closeable {

  /**
   * Returns the {@link org.apache.hadoop.conf.Configuration} object used by this instance.
   * <p>
   * The reference returned is not a copy, so any change made to it will affect this instance.
   */
  Configuration getConfiguration();

  /**
   * Retrieve a AsyncRegionLocator implementation to inspect region information on a table. The
   * returned AsyncRegionLocator is not thread-safe, so a new instance should be created for each
   * using thread. This is a lightweight operation. Pooling or caching of the returned
   * AsyncRegionLocator is neither required nor desired.
   * @param tableName Name of the table who's region is to be examined
   * @return An AsyncRegionLocator instance
   */
  AsyncTableRegionLocator getRegionLocator(TableName tableName);

  /**
   * Retrieve an {@link RawAsyncTable} implementation for accessing a table.
   * <p>
   * The returned instance will use default configs. Use {@link #getRawTableBuilder(TableName)} if you
   * want to customize some configs.
   * <p>
   * This method no longer checks table existence. An exception will be thrown if the table does not
   * exist only when the first operation is attempted.
   * @param tableName the name of the table
   * @return an RawAsyncTable to use for interactions with this table
   * @see #getRawTableBuilder(TableName)
   */
  default RawAsyncTable getRawTable(TableName tableName) {
    return getRawTableBuilder(tableName).build();
  }

  /**
   * Returns an {@link AsyncTableBuilder} for creating {@link RawAsyncTable}.
   * <p>
   * This method no longer checks table existence. An exception will be thrown if the table does not
   * exist only when the first operation is attempted.
   * @param tableName the name of the table
   */
  AsyncTableBuilder<RawAsyncTable> getRawTableBuilder(TableName tableName);

  /**
   * Retrieve an AsyncTable implementation for accessing a table.
   * <p>
   * This method no longer checks table existence. An exception will be thrown if the table does not
   * exist only when the first operation is attempted.
   * @param tableName the name of the table
   * @param pool the thread pool to use for executing callback
   * @return an AsyncTable to use for interactions with this table
   */
  default AsyncTable getTable(TableName tableName, ExecutorService pool) {
    return getTableBuilder(tableName, pool).build();
  }

  /**
   * Returns an {@link AsyncTableBuilder} for creating {@link AsyncTable}.
   * <p>
   * This method no longer checks table existence. An exception will be thrown if the table does not
   * exist only when the first operation is attempted.
   * @param tableName the name of the table
   * @param pool the thread pool to use for executing callback
   */
  AsyncTableBuilder<AsyncTable> getTableBuilder(TableName tableName, ExecutorService pool);

  /**
   * Retrieve an AsyncAdmin implementation to administer an HBase cluster. The returned AsyncAdmin
   * is not guaranteed to be thread-safe. A new instance should be created for each using thread.
   * This is a lightweight operation. Pooling or caching of the returned AsyncAdmin is not
   * recommended.
   * @return an AsyncAdmin instance for cluster administration
   */
  AsyncAdmin getAdmin();
}