alluxio-master-2.x/core/server/master/src/main/java/alluxio/master/block/BlockContainerIdGenerator.java
/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the "License"). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio.master.block;

import java.util.concurrent.atomic.AtomicLong;
import javax.annotation.concurrent.ThreadSafe;

/**
 * This class generates unique block container ids.
 */
@ThreadSafe
public final class BlockContainerIdGenerator implements ContainerIdGenerable {

  private final AtomicLong mNextContainerId;

  /**
   * Creates a new instance of {@link BlockContainerIdGenerator}.
   */
  public BlockContainerIdGenerator() {
    mNextContainerId = new AtomicLong(0);
  }

  @Override
  public long getNewContainerId() {
    return mNextContainerId.getAndIncrement();
  }

  /**
   * @return a unique block container id, and is used
   */
  public long getNextContainerId() {
    return mNextContainerId.get();
  }

  /**
   * @return the next container id
   */
  public long peekNewContainerId() {
    return mNextContainerId.get();
  }

  /**
   * @param id the next container id to use
   */
  public void setNextContainerId(long id) {
    mNextContainerId.set(id);
  }
}
