org.apache.hadoop.hbase.client.RequestController Maven / Gradle / Ivy
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* 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.InterruptedIOException;
import java.util.Collection;
import java.util.function.Consumer;
import org.apache.hadoop.hbase.HRegionLocation;
import org.apache.hadoop.hbase.ServerName;
import org.apache.yetus.audience.InterfaceAudience;
/**
* An interface for client request scheduling algorithm.
*/
@InterfaceAudience.Public
public interface RequestController {
@InterfaceAudience.Public
public enum ReturnCode {
/**
* Accept current row.
*/
INCLUDE,
/**
* Skip current row.
*/
SKIP,
/**
* No more row can be included.
*/
END
}
/**
* Picks up the valid data.
*/
@InterfaceAudience.Public
public interface Checker {
/**
* Checks the data whether it is valid to submit.
* @param loc the destination of data
* @param row the data to check
* @return describe the decision for the row
*/
ReturnCode canTakeRow(HRegionLocation loc, Row row);
/**
* Reset the state of the scheduler when completing the iteration of rows.
* @throws InterruptedIOException some controller may wait for some busy region or RS to
* complete the undealt request.
*/
void reset() throws InterruptedIOException;
}
/** Returns A new checker for evaluating a batch rows. */
Checker newChecker();
/**
* Increment the counter if we build a valid task.
* @param regions The destination of task
* @param sn The target server
*/
void incTaskCounters(Collection regions, ServerName sn);
/**
* Decrement the counter if a task is accomplished.
* @param regions The destination of task
* @param sn The target server
*/
void decTaskCounters(Collection regions, ServerName sn);
/** Returns The number of running task. */
long getNumberOfTasksInProgress();
/**
* Waits for the running tasks to complete. If there are specified threshold and trigger, the
* implementation should wake up once in a while for checking the threshold and calling trigger.
* @param max This method will return if the number of running tasks is less than or
* equal to max.
* @param id the caller's id
* @param periodToTrigger The period to invoke the trigger. This value is a hint. The real period
* depends on the implementation.
* @param trigger The object to call periodically.
* @throws java.io.InterruptedIOException If the waiting is interrupted
*/
void waitForMaximumCurrentTasks(long max, long id, int periodToTrigger, Consumer trigger)
throws InterruptedIOException;
/**
* Wait until there is at least one slot for a new task.
* @param id the caller's id
* @param periodToTrigger The period to invoke the trigger. This value is a hint. The real period
* depends on the implementation.
* @param trigger The object to call periodically.
* @throws java.io.InterruptedIOException If the waiting is interrupted
*/
void waitForFreeSlot(long id, int periodToTrigger, Consumer trigger)
throws InterruptedIOException;
}