/**
 * 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.hadoop.hdfs.server.federation.router;

import java.io.IOException;

/**
 * Result from a remote location.
 * It includes the exception if there was any error.
 * @param <T> Type of the remote location.
 * @param <R> Type of the result.
 */
public class RemoteResult<T extends RemoteLocationContext, R> {
  /** The remote location. */
  private final T loc;
  /** The result from the remote location. */
  private final R result;
  /** If the result is set; used for void types. */
  private final boolean resultSet;
  /** The exception if we couldn't get the result. */
  private final IOException ioe;

  public RemoteResult(T location, R r) {
    this.loc = location;
    this.result = r;
    this.resultSet = true;
    this.ioe = null;
  }

  public RemoteResult(T location, IOException e) {
    this.loc = location;
    this.result = null;
    this.resultSet = false;
    this.ioe = e;
  }

  public T getLocation() {
    return loc;
  }

  public boolean hasResult() {
    return resultSet;
  }

  public R getResult() {
    return result;
  }

  public boolean hasException() {
    return getException() != null;
  }

  public IOException getException() {
    return ioe;
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder()
        .append("loc=").append(getLocation());
    if (hasResult()) {
      sb.append(" result=").append(getResult());
    }
    if (hasException()) {
      sb.append(" exception=").append(getException());
    }
    return sb.toString();
  }
}