| // Copyright (C) 2016 The Android Open Source Project |
| // |
| // Licensed 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 com.googlesource.gerrit.plugins.events; |
| |
| import java.util.Map; |
| import java.util.UUID; |
| import java.util.concurrent.ConcurrentHashMap; |
| import javax.inject.Singleton; |
| |
| @Singleton |
| public class MemStore implements EventStore { |
| protected final Map<Long, String> eventsByIndex = new ConcurrentHashMap<Long, String>(); |
| protected final UUID uuid; |
| |
| protected long head = 0; |
| protected long tail = 1; |
| |
| public MemStore() { |
| uuid = UUID.randomUUID(); |
| } |
| |
| @Override |
| public UUID getUuid() { |
| return uuid; |
| } |
| |
| @Override |
| public synchronized void add(String event) { |
| eventsByIndex.put(head + 1, event); |
| head++; |
| } |
| |
| @Override |
| public String get(long n) { |
| return eventsByIndex.get(n); |
| } |
| |
| @Override |
| public long getHead() { |
| return head; |
| } |
| |
| @Override |
| public long getTail() { |
| return head == 0 ? 0 : tail; |
| } |
| |
| @Override |
| public void trim(long trim) { |
| if (trim >= head) { |
| trim = head - 1; |
| } |
| for (long i = tail; i <= trim; i++) { |
| tail++; |
| eventsByIndex.remove(i); |
| } |
| } |
| } |