org.apache.hadoop.hbase.client.RetryingCallable Maven / Gradle / Ivy
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
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*/
package org.apache.hadoop.hbase.client;
import java.io.IOException;
import org.apache.yetus.audience.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 result class from executing this
*/
@InterfaceAudience.Private
public interface RetryingCallable {
/**
* 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);
/**
* Returns 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();
/**
* Sleep and retry.
* @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;
}