Carmelo Cascone | da15af8 | 2019-12-09 22:36:48 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2019-present Open Networking Foundation |
| 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 | */ |
| 16 | |
| 17 | package org.onosproject.pipelines.fabric.impl.behaviour.bng; |
| 18 | |
| 19 | import com.google.common.collect.BiMap; |
| 20 | import com.google.common.collect.HashBiMap; |
| 21 | import com.google.common.collect.Lists; |
| 22 | |
| 23 | import java.util.NoSuchElementException; |
| 24 | import java.util.Queue; |
| 25 | |
| 26 | import static org.onosproject.net.behaviour.BngProgrammable.Attachment; |
| 27 | |
| 28 | /** |
| 29 | * Trivial, thread-safe, non-distributed implementation of {@link |
| 30 | * FabricBngLineIdAllocator}. |
| 31 | */ |
| 32 | final class SimpleBngLineIdAllocator implements FabricBngLineIdAllocator { |
| 33 | |
| 34 | private final long size; |
| 35 | private final BiMap<Handle, Long> allocated = HashBiMap.create(); |
| 36 | private final Queue<Long> released = Lists.newLinkedList(); |
| 37 | |
| 38 | /** |
| 39 | * Creates a new allocator that can allocate and hold up to the given number |
| 40 | * of IDs. |
| 41 | * |
| 42 | * @param size maximum number of IDs to allocate. |
| 43 | */ |
| 44 | SimpleBngLineIdAllocator(long size) { |
| 45 | this.size = size; |
| 46 | for (long i = 0; i < size; i++) { |
| 47 | released.add(i); |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | @Override |
| 52 | public long allocate(Attachment attachment) throws IdExhaustedException { |
| 53 | final Handle handle = new Handle(attachment); |
| 54 | synchronized (this) { |
| 55 | if (allocated.containsKey(handle)) { |
| 56 | return allocated.get(handle); |
| 57 | } |
| 58 | try { |
| 59 | final long id = released.remove(); |
| 60 | allocated.put(handle, id); |
| 61 | return id; |
| 62 | } catch (NoSuchElementException e) { |
| 63 | // All IDs are taken; |
| 64 | throw new IdExhaustedException(); |
| 65 | } |
| 66 | } |
| 67 | } |
| 68 | |
| 69 | @Override |
| 70 | public void release(Attachment attachment) { |
| 71 | final Handle handle = new Handle(attachment); |
| 72 | synchronized (this) { |
| 73 | Long id = allocated.remove(handle); |
| 74 | if (id != null) { |
| 75 | released.add(id); |
| 76 | } |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | @Override |
| 81 | public void release(long id) { |
| 82 | synchronized (this) { |
| 83 | if (allocated.inverse().containsKey(id)) { |
| 84 | allocated.inverse().remove(id); |
| 85 | released.add(id); |
| 86 | } |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | @Override |
| 91 | public long size() { |
| 92 | return size; |
| 93 | } |
| 94 | |
| 95 | @Override |
| 96 | public long freeCount() { |
| 97 | return released.size(); |
| 98 | } |
| 99 | |
| 100 | @Override |
| 101 | public long allocatedCount() { |
| 102 | return allocated.size(); |
| 103 | } |
| 104 | } |