core/src/main/java/org/apache/accumulo/core/client/BatchWriter.java

/*
 * 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.accumulo.core.client;

import org.apache.accumulo.core.data.Mutation;

/**
 * Send Mutations to a single Table in Accumulo.
 * <p>
 * When the user uses a Connector to create a BatchWriter, they specify how much memory and how many
 * threads it should use. As the user adds mutations to the batch writer, it buffers them. Once the
 * buffered mutations have used half of the user specified buffer, the mutations are dumped into the
 * background to be written by a thread pool. If the user specified memory completely fills up, then
 * writes are held. When a user calls flush, it does not return until all buffered mutations are
 * written.
 * <p>
 * In the event that an MutationsRejectedException exception is thrown by one of the methods on a
 * BatchWriter instance, the user should close the current instance and create a new instance. This
 * is a known limitation which will be addressed by ACCUMULO-2990 in the future.
 */
public interface BatchWriter extends AutoCloseable {

  /**
   * Queues one mutation to write.
   *
   * @param m
   *          the mutation to add
   * @throws MutationsRejectedException
   *           this could be thrown because current or previous mutations failed
   */

  void addMutation(Mutation m) throws MutationsRejectedException;

  /**
   * Queues several mutations to write.
   *
   * @param iterable
   *          allows adding any number of mutations iteratively
   * @throws MutationsRejectedException
   *           this could be thrown because current or previous mutations failed
   */
  void addMutations(Iterable<Mutation> iterable) throws MutationsRejectedException;

  /**
   * Send any buffered mutations to Accumulo immediately.
   *
   * @throws MutationsRejectedException
   *           this could be thrown because current or previous mutations failed
   */
  void flush() throws MutationsRejectedException;

  /**
   * Flush and release any resources.
   *
   * @throws MutationsRejectedException
   *           this could be thrown because current or previous mutations failed
   */
  @Override
  void close() throws MutationsRejectedException;

}