/*
 * 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.oss.driver.api.core.servererrors;

import com.datastax.oss.driver.api.core.AllNodesFailedException;
import com.datastax.oss.driver.api.core.ConsistencyLevel;
import com.datastax.oss.driver.api.core.DriverException;
import com.datastax.oss.driver.api.core.cql.ExecutionInfo;
import com.datastax.oss.driver.api.core.metadata.Node;
import com.datastax.oss.driver.api.core.retry.RetryPolicy;
import com.datastax.oss.driver.api.core.session.Request;
import edu.umd.cs.findbugs.annotations.NonNull;

A server-side timeout during a read query.
This exception is processed by RetryPolicy.onReadTimeout(Request, ConsistencyLevel, int, int, boolean, int), which will decide if it is rethrown directly to the client or if the request should be retried. If all other tried nodes also fail, this exception will appear in the AllNodesFailedException thrown to the client. /**
 * A server-side timeout during a read query.
 *
 * <p>This exception is processed by {@link RetryPolicy#onReadTimeout(Request, ConsistencyLevel,
 * int, int, boolean, int)}, which will decide if it is rethrown directly to the client or if the
 * request should be retried. If all other tried nodes also fail, this exception will appear in the
 * {@link AllNodesFailedException} thrown to the client.
 */
public class ReadTimeoutException extends QueryConsistencyException {

  private final boolean dataPresent;

  public ReadTimeoutException(
      @NonNull Node coordinator,
      @NonNull ConsistencyLevel consistencyLevel,
      int received,
      int blockFor,
      boolean dataPresent) {
    this(
        coordinator,
        String.format(
            "Cassandra timeout during read query at consistency %s (%s)",
            consistencyLevel, formatDetails(received, blockFor, dataPresent)),
        consistencyLevel,
        received,
        blockFor,
        dataPresent,
        null,
        false);
  }

  private ReadTimeoutException(
      @NonNull Node coordinator,
      @NonNull String message,
      @NonNull ConsistencyLevel consistencyLevel,
      int received,
      int blockFor,
      boolean dataPresent,
      ExecutionInfo executionInfo,
      boolean writableStackTrace) {
    super(
        coordinator,
        message,
        consistencyLevel,
        received,
        blockFor,
        executionInfo,
        writableStackTrace);
    this.dataPresent = dataPresent;
  }

  private static String formatDetails(int received, int blockFor, boolean dataPresent) {
    if (received < blockFor) {
      return String.format(
          "%d responses were required but only %d replica responded", blockFor, received);
    } else if (!dataPresent) {
      return "the replica queried for data didn't respond";
    } else {
      return "timeout while waiting for repair of inconsistent replica";
    }
  }

  
Whether the actual data was amongst the received replica responses.
During reads, Cassandra doesn't request data from every replica to minimize internal network
traffic. Instead, some replicas are only asked for a checksum of the data. A read timeout may
occur even if enough replicas have responded to fulfill the consistency level, if only checksum
responses have been received. This method allows to detect that case.
/**
   * Whether the actual data was amongst the received replica responses.
   *
   * <p>During reads, Cassandra doesn't request data from every replica to minimize internal network
   * traffic. Instead, some replicas are only asked for a checksum of the data. A read timeout may
   * occur even if enough replicas have responded to fulfill the consistency level, if only checksum
   * responses have been received. This method allows to detect that case.
   */
  public boolean wasDataPresent() {
    return dataPresent;
  }

  @NonNull
  @Override
  public DriverException copy() {
    return new ReadTimeoutException(
        getCoordinator(),
        getMessage(),
        getConsistencyLevel(),
        getReceived(),
        getBlockFor(),
        dataPresent,
        getExecutionInfo(),
        true);
  }
}