com.datastax.driver.core.exceptions.UnavailableException Maven / Gradle / Ivy

/*
 * Copyright DataStax, Inc.
 *
 * Licensed 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 com.datastax.driver.core.exceptions;

import com.datastax.driver.core.ConsistencyLevel;
import com.datastax.driver.core.EndPoint;
import java.net.InetAddress;
import java.net.InetSocketAddress;

/**
 * Exception thrown when the coordinator knows there is not enough replicas alive to perform a query
 * with the requested consistency level.
 */
public class UnavailableException extends QueryExecutionException implements CoordinatorException {

  private static final long serialVersionUID = 0;

  private final EndPoint endPoint;
  private final ConsistencyLevel consistency;
  private final int required;
  private final int alive;

  /**
   * This constructor should only be used internally by the driver when decoding error responses.
   */
  public UnavailableException(ConsistencyLevel consistency, int required, int alive) {
    this(null, consistency, required, alive);
  }

  public UnavailableException(
      EndPoint endPoint, ConsistencyLevel consistency, int required, int alive) {
    super(
        String.format(
            "Not enough replicas available for query at consistency %s (%d required but only %d alive)",
            consistency, required, alive));
    this.endPoint = endPoint;
    this.consistency = consistency;
    this.required = required;
    this.alive = alive;
  }

  private UnavailableException(
      EndPoint endPoint,
      String message,
      Throwable cause,
      ConsistencyLevel consistency,
      int required,
      int alive) {
    super(message, cause);
    this.endPoint = endPoint;
    this.consistency = consistency;
    this.required = required;
    this.alive = alive;
  }

  /**
   * The consistency level of the operation triggering this unavailable exception.
   *
   * @return the consistency level of the operation triggering this unavailable exception.
   */
  public ConsistencyLevel getConsistencyLevel() {
    return consistency;
  }

  /**
   * The number of replica acknowledgements/responses required to perform the operation (with its
   * required consistency level).
   *
   * @return the number of replica acknowledgements/responses required to perform the operation.
   */
  public int getRequiredReplicas() {
    return required;
  }

  /**
   * The number of replicas that were known to be alive by the Cassandra coordinator node when it
   * tried to execute the operation.
   *
   * @return The number of replicas that were known to be alive by the Cassandra coordinator node
   *     when it tried to execute the operation.
   */
  public int getAliveReplicas() {
    return alive;
  }

  @Override
  public EndPoint getEndPoint() {
    return endPoint;
  }

  @Override
  @Deprecated
  public InetSocketAddress getAddress() {
    return (endPoint == null) ? null : endPoint.resolve();
  }

  @Override
  @Deprecated
  public InetAddress getHost() {
    return (endPoint == null) ? null : endPoint.resolve().getAddress();
  }

  @Override
  public UnavailableException copy() {
    return new UnavailableException(
        getEndPoint(), getMessage(), this, consistency, required, alive);
  }

  /**
   * Create a copy of this exception with a nicer stack trace, and including the coordinator address
   * that caused this exception to be raised.
   *
   * This method is mainly intended for internal use by the driver and exists mainly because:
   *
   * 

   *   the original exception was decoded from a response frame and at that time, the
   *       coordinator address was not available; and
   *   
the newly-created exception will refer to the current thread in its stack trace, which
   *       generally yields a more user-friendly stack trace that the original one.
   * 
   *
   * @param endPoint The full connection information of the host that caused this exception to be
   *     thrown.
   * @return a copy/clone of this exception, but with the given host address instead of the original
   *     one.
   */
  public UnavailableException copy(EndPoint endPoint) {
    return new UnavailableException(endPoint, getMessage(), this, consistency, required, alive);
  }
}