/**
*
* 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.hbase.client;
import java.io.IOException;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
/**
* A Callable<T> that will be retried. If {@link #call(int)} invocation throws exceptions,
* we will call {@link #throwable(Throwable, boolean)} with whatever the exception was.
* @param <T> result class from executing <tt>this</tt>
*/
@InterfaceAudience.Private
public interface RetryingCallable<T> {
/**
* Prepare by setting up any connections to servers, etc., ahead of call invocation.
* TODO: We call prepare before EVERY call. Seems wrong. FIX!!!!
* @param reload Set this to true if need to requery locations
* @throws IOException e
*/
void prepare(final boolean reload) throws IOException;
/**
* Called when call throws an exception and we are going to retry; take action to
* make it so we succeed on next call (clear caches, do relookup of locations, etc.).
* @param t throwable which was thrown
* @param retrying True if we are in retrying mode (we are not in retrying mode when max
* retries == 1; we ARE in retrying mode if retries > 1 even when we are the
* last attempt)
*/
void throwable(final Throwable t, boolean retrying);
/**
* @return Some details from the implementation that we would like to add to a terminating
* exception; i.e. a fatal exception is being thrown ending retries and we might like to
* add more implementation-specific detail on to the exception being thrown.
*/
String getExceptionMessageAdditionalDetail();
/**
* @param pause time to pause
* @param tries amount of tries until till sleep
* @return Suggestion on how much to sleep between retries
*/
long sleep(final long pause, final int tries);
/**
* Computes a result, or throws an exception if unable to do so.
*
* @param callTimeout - the time available for this call. 0 for infinite.
* @return computed result
* @throws Exception if unable to compute a result
*/
T call(int callTimeout) throws Exception;
}