alshabib | ab98466 | 2014-12-04 18:56:18 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2014 Open Networking Laboratory |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
Brian O'Connor | abafb50 | 2014-12-02 22:26:20 -0800 | [diff] [blame] | 16 | package org.onosproject.core.impl; |
Brian O'Connor | 520c052 | 2014-11-23 23:50:47 -0800 | [diff] [blame] | 17 | |
Madan Jampani | 66feabf | 2015-06-05 12:24:20 -0700 | [diff] [blame] | 18 | import java.util.concurrent.atomic.AtomicBoolean; |
| 19 | |
Brian O'Connor | abafb50 | 2014-12-02 22:26:20 -0800 | [diff] [blame] | 20 | import org.onosproject.core.IdBlock; |
| 21 | import org.onosproject.core.IdGenerator; |
| 22 | import org.onosproject.core.UnavailableIdException; |
Brian O'Connor | 520c052 | 2014-11-23 23:50:47 -0800 | [diff] [blame] | 23 | |
Brian O'Connor | 390c997 | 2015-06-24 16:08:09 -0400 | [diff] [blame] | 24 | import static com.google.common.base.Preconditions.checkNotNull; |
| 25 | |
Brian O'Connor | 520c052 | 2014-11-23 23:50:47 -0800 | [diff] [blame] | 26 | /** |
| 27 | * Base class of {@link IdGenerator} implementations which use {@link IdBlockAllocator} as |
| 28 | * backend. |
| 29 | */ |
| 30 | public class BlockAllocatorBasedIdGenerator implements IdGenerator { |
| 31 | protected final IdBlockAllocator allocator; |
Madan Jampani | c80da08 | 2015-06-03 00:26:21 -0700 | [diff] [blame] | 32 | protected IdBlock idBlock; |
Madan Jampani | 66feabf | 2015-06-05 12:24:20 -0700 | [diff] [blame] | 33 | protected AtomicBoolean initialized; |
| 34 | |
Brian O'Connor | 520c052 | 2014-11-23 23:50:47 -0800 | [diff] [blame] | 35 | |
| 36 | /** |
| 37 | * Constructs an ID generator which use {@link IdBlockAllocator} as backend. |
| 38 | * |
Pavlin Radoslavov | 119fd5c | 2014-11-25 19:08:19 -0800 | [diff] [blame] | 39 | * @param allocator the ID block allocator to use |
Brian O'Connor | 520c052 | 2014-11-23 23:50:47 -0800 | [diff] [blame] | 40 | */ |
| 41 | protected BlockAllocatorBasedIdGenerator(IdBlockAllocator allocator) { |
Brian O'Connor | 390c997 | 2015-06-24 16:08:09 -0400 | [diff] [blame] | 42 | this.allocator = checkNotNull(allocator, "allocator cannot be null"); |
Madan Jampani | 66feabf | 2015-06-05 12:24:20 -0700 | [diff] [blame] | 43 | this.initialized = new AtomicBoolean(false); |
Brian O'Connor | 520c052 | 2014-11-23 23:50:47 -0800 | [diff] [blame] | 44 | } |
| 45 | |
| 46 | @Override |
| 47 | public long getNewId() { |
| 48 | try { |
alshabib | 5f5d281 | 2015-07-02 18:43:19 -0700 | [diff] [blame] | 49 | if (!initialized.get()) { |
| 50 | synchronized (allocator) { |
| 51 | if (!initialized.get()) { |
| 52 | idBlock = allocator.allocateUniqueIdBlock(); |
| 53 | initialized.set(true); |
| 54 | } |
| 55 | } |
| 56 | } |
Madan Jampani | c80da08 | 2015-06-03 00:26:21 -0700 | [diff] [blame] | 57 | return idBlock.getNextId(); |
Brian O'Connor | 520c052 | 2014-11-23 23:50:47 -0800 | [diff] [blame] | 58 | } catch (UnavailableIdException e) { |
| 59 | synchronized (allocator) { |
Madan Jampani | c80da08 | 2015-06-03 00:26:21 -0700 | [diff] [blame] | 60 | idBlock = allocator.allocateUniqueIdBlock(); |
Brian O'Connor | 520c052 | 2014-11-23 23:50:47 -0800 | [diff] [blame] | 61 | } |
Madan Jampani | 66feabf | 2015-06-05 12:24:20 -0700 | [diff] [blame] | 62 | return idBlock.getNextId(); |
Brian O'Connor | 520c052 | 2014-11-23 23:50:47 -0800 | [diff] [blame] | 63 | } |
| 64 | } |
| 65 | } |