content: /*
   * 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.client.block.policy;
  
  import alluxio.client.block.BlockWorkerInfo;
  import alluxio.client.block.policy.options.GetWorkerOptions;
  import alluxio.conf.AlluxioConfiguration;
  import alluxio.conf.PropertyKey;
  import alluxio.wire.WorkerNetAddress;
  
  import com.google.common.base.MoreObjects;
  import com.google.common.base.Objects;
  import com.google.common.base.Preconditions;
  
  import java.util.Optional;
  import javax.annotation.Nullable;
  import javax.annotation.concurrent.ThreadSafe;
  
  /**
   * Always returns a worker with the hostname specified by
   * {@link PropertyKey#WORKER_HOSTNAME} (alluxio.worker.hostname).
   */
  @ThreadSafe
  public final class SpecificHostPolicy implements BlockLocationPolicy {
    private final String mHostname;
    @Nullable
    private final Integer mRpcPort;
  
    /**
     * Constructs a new {@link SpecificHostPolicy}
     * needed for instantiation in {@link BlockLocationPolicy.Factory}.
     *
     * @param conf Alluxio configuration
     */
    public SpecificHostPolicy(AlluxioConfiguration conf) {
      this(conf.getString(PropertyKey.WORKER_HOSTNAME), conf.getInt(PropertyKey.WORKER_RPC_PORT));
    }
  
    /**
     * Constructs the policy with the hostname.
     *
     * @param hostname the name of the host
     */
    public SpecificHostPolicy(String hostname) {
      this(hostname, null);
    }
  
    /**
     * Constructs the policy with the hostname and port.
     *
     * @param hostname the name of the host
     * @param rpcPort the rpc port
     */
    public SpecificHostPolicy(String hostname, @Nullable Integer rpcPort) {
      mHostname = Preconditions.checkNotNull(hostname, "hostname");
      mRpcPort = rpcPort;
    }
  
    /**
     * Returns null if no active worker matches the hostname
     * provided in WORKER_HOSTNAME (alluxio.worker.hostname).
     */
    @Override
    public Optional<WorkerNetAddress> getWorker(GetWorkerOptions options) {
      // find the first worker matching the host name
      for (BlockWorkerInfo info : options.getBlockWorkerInfos()) {
        if (info.getNetAddress().getHost().equals(mHostname)
            && (mRpcPort == null || info.getNetAddress().getRpcPort() == mRpcPort)) {
          return Optional.of(info.getNetAddress());
        }
      }
      return Optional.empty();
    }
  
    @Override
    public boolean equals(Object o) {
      if (this == o) {
        return true;
      }
      if (!(o instanceof SpecificHostPolicy)) {
        return false;
      }
      SpecificHostPolicy that = (SpecificHostPolicy) o;
      return Objects.equal(mHostname, that.mHostname);
    }
  
    @Override
    public int hashCode() {
      return Objects.hashCode(mHostname);
    }
  
    @Override
    public String toString() {
      return MoreObjects.toStringHelper(this)
          .add("hostname", mHostname)
          .toString();
    }
  }
  