001/** 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 019package org.apache.hadoop.hbase.procedure2; 020 021import java.util.Collections; 022import java.util.List; 023import org.apache.yetus.audience.InterfaceAudience; 024import org.apache.yetus.audience.InterfaceStability; 025 026/** 027 * Simple scheduler for procedures 028 */ 029@InterfaceAudience.Private 030@InterfaceStability.Evolving 031public class SimpleProcedureScheduler extends AbstractProcedureScheduler { 032 private final ProcedureDeque runnables = new ProcedureDeque(); 033 034 @Override 035 protected void enqueue(final Procedure procedure, final boolean addFront) { 036 if (addFront) { 037 runnables.addFirst(procedure); 038 } else { 039 runnables.addLast(procedure); 040 } 041 } 042 043 @Override 044 protected Procedure dequeue() { 045 return runnables.poll(); 046 } 047 048 @Override 049 public void clear() { 050 schedLock(); 051 try { 052 runnables.clear(); 053 } finally { 054 schedUnlock(); 055 } 056 } 057 058 @Override 059 public void yield(final Procedure proc) { 060 addBack(proc); 061 } 062 063 @Override 064 public boolean queueHasRunnables() { 065 return runnables.size() > 0; 066 } 067 068 @Override 069 public int queueSize() { 070 return runnables.size(); 071 } 072 073 @Override 074 public void completionCleanup(Procedure proc) { 075 } 076 077 @Override 078 public List<LockedResource> getLocks() { 079 return Collections.emptyList(); 080 } 081 082 @Override 083 public LockedResource getLockResource(LockedResourceType resourceType, 084 String resourceName) { 085 return null; 086 } 087}