hbase-client/src/main/java/org/apache/hadoop/hbase/client/RequestController.java

   1 /*
   2  *
   3  * Licensed to the Apache Software Foundation (ASF) under one
   4  * or more contributor license agreements.  See the NOTICE file
   5  * distributed with this work for additional information
   6  * regarding copyright ownership.  The ASF licenses this file
   7  * to you under the Apache License, Version 2.0 (the
   8  * "License"); you may not use this file except in compliance
   9  * with the License.  You may obtain a copy of the License at
  10  *
  11  *     http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  */
  19
  20 package org.apache.hadoop.hbase.client;
  21
  22 import java.io.InterruptedIOException;
  23 import java.util.Collection;
  24 import java.util.function.Consumer;
  25 import org.apache.hadoop.hbase.HRegionLocation;
  26 import org.apache.hadoop.hbase.ServerName;
  27 import org.apache.yetus.audience.InterfaceAudience;
  28
  29 /**
  30  * An interface for client request scheduling algorithm.
  31  */
  32 @InterfaceAudience.Public
  33 public interface RequestController {
  34
  35   @InterfaceAudience.Public
  36   public enum ReturnCode {
  37     /**
  38      * Accept current row.
  39      */
  40     INCLUDE,
  41     /**
  42      * Skip current row.
  43      */
  44     SKIP,
  45     /**
  46      * No more row can be included.
  47      */
  48     END
  49   }
  50
  51   /**
  52    * Picks up the valid data.
  53    */
  54   @InterfaceAudience.Public
  55   public interface Checker {
  56     /**
  57      * Checks the data whether it is valid to submit.
  58      * @param loc the destination of data
  59      * @param row the data to check
  60      * @return describe the decision for the row
  61      */
  62     ReturnCode canTakeRow(HRegionLocation loc, Row row);
  63
  64     /**
  65      * Reset the state of the scheduler when completing the iteration of rows.
  66      * @throws InterruptedIOException some controller may wait
  67      * for some busy region or RS to complete the undealt request.
  68      */
  69     void reset() throws InterruptedIOException ;
  70   }
  71
  72   /**
  73    * @return A new checker for evaluating a batch rows.
  74    */
  75   Checker newChecker();
  76
  77   /**
  78    * Increment the counter if we build a valid task.
  79    * @param regions The destination of task
  80    * @param sn The target server
  81    */
  82   void incTaskCounters(Collection<byte[]> regions, ServerName sn);
  83
  84   /**
  85    * Decrement the counter if a task is accomplished.
  86    * @param regions The destination of task
  87    * @param sn The target server
  88    */
  89   void decTaskCounters(Collection<byte[]> regions, ServerName sn);
  90
  91   /**
  92    * @return The number of running task.
  93    */
  94   long getNumberOfTasksInProgress();
  95
  96   /**
  97    * Waits for the running tasks to complete.
  98    * If there are specified threshold and trigger, the implementation should
  99    * wake up once in a while for checking the threshold and calling trigger.
 100    * @param max This method will return if the number of running tasks is
 101    * less than or equal to max.
 102    * @param id the caller's id
 103    * @param periodToTrigger The period to invoke the trigger. This value is a
 104    * hint. The real period depends on the implementation.
 105    * @param trigger The object to call periodically.
 106    * @throws java.io.InterruptedIOException If the waiting is interrupted
 107    */
 108   void waitForMaximumCurrentTasks(long max, long id,
 109     int periodToTrigger, Consumer<Long> trigger) throws InterruptedIOException;
 110
 111   /**
 112    * Wait until there is at least one slot for a new task.
 113    * @param id the caller's id
 114    * @param periodToTrigger The period to invoke the trigger. This value is a
 115    * hint. The real period depends on the implementation.
 116    * @param trigger The object to call periodically.
 117    * @throws java.io.InterruptedIOException If the waiting is interrupted
 118    */
 119   void waitForFreeSlot(long id, int periodToTrigger,
 120           Consumer<Long> trigger) throws InterruptedIOException;
 121 }