| /* |
| * Copyright 2017-present Open Networking Foundation |
| * |
| * 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 org.onosproject.store.primitives.resources.impl; |
| |
| import java.util.concurrent.CompletableFuture; |
| import java.util.concurrent.atomic.AtomicLong; |
| |
| import org.onosproject.store.service.AsyncAtomicCounter; |
| import org.onosproject.store.service.AsyncAtomicIdGenerator; |
| |
| /** |
| * {@code AsyncAtomicIdGenerator} implementation backed by Atomix |
| * {@link AsyncAtomicCounter}. |
| */ |
| public class AtomixIdGenerator implements AsyncAtomicIdGenerator { |
| |
| private static final long DEFAULT_BATCH_SIZE = 1000; |
| private final AsyncAtomicCounter counter; |
| private final long batchSize; |
| private CompletableFuture<Long> reserveFuture; |
| private long base; |
| private final AtomicLong delta = new AtomicLong(); |
| |
| public AtomixIdGenerator(AsyncAtomicCounter counter) { |
| this(counter, DEFAULT_BATCH_SIZE); |
| } |
| |
| AtomixIdGenerator(AsyncAtomicCounter counter, long batchSize) { |
| this.counter = counter; |
| this.batchSize = batchSize; |
| } |
| |
| @Override |
| public String name() { |
| return counter.name(); |
| } |
| |
| @Override |
| public synchronized CompletableFuture<Long> nextId() { |
| long nextDelta = delta.incrementAndGet(); |
| if ((base == 0 && reserveFuture == null) || nextDelta > batchSize) { |
| delta.set(0); |
| long delta = this.delta.incrementAndGet(); |
| return reserve().thenApply(base -> base + delta); |
| } else { |
| return reserveFuture.thenApply(base -> base + nextDelta); |
| } |
| } |
| |
| private CompletableFuture<Long> reserve() { |
| if (reserveFuture == null || reserveFuture.isDone()) { |
| reserveFuture = counter.getAndAdd(batchSize); |
| } else { |
| reserveFuture = reserveFuture.thenCompose(v -> counter.getAndAdd(batchSize)); |
| } |
| reserveFuture = reserveFuture.thenApply(base -> { |
| this.base = base; |
| return base; |
| }); |
| return reserveFuture; |
| } |
| } |