library/src/main/java/org/apache/apex/malhar/lib/join/Bucket.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.apex.malhar.lib.join;

import java.util.List;
import java.util.Map;

import org.apache.hadoop.classification.InterfaceStability;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;

/**
 * <p>
 * This is the base implementation of bucket which contains all the events which belong to the same bucket.
 * </p>
 *
 * @param <T> type of bucket events
 *
 * @since 3.4.0
 */
@InterfaceStability.Unstable
public class Bucket<T extends TimeEvent>
{
  public final long bucketKey;
  protected Map<Object, List<T>> unwrittenEvents;

  public Bucket()
  {
    bucketKey = -1L;
  }

  protected Bucket(long bucketKey)
  {
    this.bucketKey = bucketKey;
  }

  /**
   * Add the given event into the unwritternEvents map
   *
   * @param eventKey event key
   * @param event Given key
   */
  protected void addNewEvent(Object eventKey, T event)
  {
    if (unwrittenEvents == null) {
      unwrittenEvents = Maps.newHashMap();
    }
    List<T> listEvents = unwrittenEvents.get(eventKey);
    if (listEvents == null) {
      unwrittenEvents.put(eventKey, Lists.newArrayList(event));
    } else {
      listEvents.add(event);
    }
  }

  /**
   * Return the unwritten events in the bucket
   *
   * @return the unwritten events
   */
  public Map<Object, List<T>> getEvents()
  {
    return unwrittenEvents;
  }

  /**
   * Return the list of events for the given key
   *
   * @param key given key
   * @return the list of events
   */
  public List<T> get(Object key)
  {
    return unwrittenEvents.get(key);
  }
}