/*
 * 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.phoenix.query;

import java.io.IOException;
import java.util.concurrent.ExecutorService;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.Table;

/**
 * Creates clients to access HBase tables.
 * @since 0.2
 */
public interface HTableFactory {
  /**
   * Creates an HBase client using an externally managed HConnection and Thread pool.
   * @param tableName  Name of the table.
   * @param connection HConnection to use.
   * @param pool       ExecutorService to use.
   * @return An client to access an HBase table.
   * @throws IOException if a server or network exception occurs
   */
  Table getTable(byte[] tableName, Connection connection, ExecutorService pool) throws IOException;

  /**
   * Default implementation. Uses standard HBase HTables.
   */
  static class HTableFactoryImpl implements HTableFactory {
    @Override
    public Table getTable(byte[] tableName, Connection connection, ExecutorService pool)
      throws IOException {
      // If CQSI_THREAD_POOL_ENABLED then we pass ExecutorService created in CQSI to
      // HBase Client, else it is null(default), let the HBase client manage the thread pool
      // There is a difference between these 2 implementations in HBase Client Code and when
      // the pool is terminated on HTable close()
      // So we need to use these 2 implementations based on value of pool.
      // If Externally provided pool is null, we use the default behavior of
      // ConnectionImplementation to manage the pool.
      if (pool == null) {
        return connection.getTable(TableName.valueOf(tableName));
      } else {
        return connection.getTable(TableName.valueOf(tableName), pool);
      }
    }
  }
}
