| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.twitter.distributedlog.benchmark.stream; |
| |
| import org.apache.bookkeeper.client.AsyncCallback; |
| import org.apache.bookkeeper.client.BKException; |
| import org.apache.bookkeeper.client.LedgerEntry; |
| import org.apache.bookkeeper.client.LedgerHandle; |
| import org.apache.bookkeeper.proto.BookkeeperInternalCallbacks.ReadEntryListener; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.util.Enumeration; |
| import java.util.concurrent.ConcurrentLinkedQueue; |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.atomic.AtomicLong; |
| |
| /** |
| * Reading ledger in a streaming way. |
| */ |
| public class LedgerStreamReader implements Runnable { |
| |
| static final Logger logger = LoggerFactory.getLogger(LedgerStreamReader.class); |
| |
| class PendingReadRequest implements AsyncCallback.ReadCallback { |
| |
| final long entryId; |
| boolean isDone = false; |
| int rc; |
| LedgerEntry entry = null; |
| |
| PendingReadRequest(long entryId) { |
| this.entryId = entryId; |
| } |
| |
| void read() { |
| lh.asyncReadEntries(entryId, entryId, this, null); |
| } |
| |
| void complete(ReadEntryListener listener) { |
| listener.onEntryComplete(rc, lh, entry, null); |
| } |
| |
| @Override |
| public void readComplete(int rc, LedgerHandle lh, Enumeration<LedgerEntry> enumeration, Object ctx) { |
| this.rc = rc; |
| if (BKException.Code.OK == rc && enumeration.hasMoreElements()) { |
| entry = enumeration.nextElement(); |
| } else { |
| entry = null; |
| } |
| isDone = true; |
| // construct a new read request |
| long nextEntry = nextReadEntry.getAndIncrement(); |
| if (nextEntry <= lac) { |
| PendingReadRequest nextRead = |
| new PendingReadRequest(nextEntry); |
| pendingReads.add(nextRead); |
| nextRead.read(); |
| } |
| triggerCallbacks(); |
| } |
| } |
| |
| private final LedgerHandle lh; |
| private final long lac; |
| private final ReadEntryListener readEntryListener; |
| private final int concurrency; |
| private final AtomicLong nextReadEntry = new AtomicLong(0); |
| private final CountDownLatch done = new CountDownLatch(1); |
| private final ConcurrentLinkedQueue<PendingReadRequest> pendingReads = |
| new ConcurrentLinkedQueue<PendingReadRequest>(); |
| |
| public LedgerStreamReader(LedgerHandle lh, |
| ReadEntryListener readEntryListener, |
| int concurrency) { |
| this.lh = lh; |
| this.lac = lh.getLastAddConfirmed(); |
| this.readEntryListener = readEntryListener; |
| this.concurrency = concurrency; |
| for (int i = 0; i < concurrency; i++) { |
| long entryId = nextReadEntry.getAndIncrement(); |
| if (entryId > lac) { |
| break; |
| } |
| PendingReadRequest request = new PendingReadRequest(entryId); |
| pendingReads.add(request); |
| request.read(); |
| } |
| if (pendingReads.isEmpty()) { |
| done.countDown(); |
| } |
| } |
| |
| synchronized void triggerCallbacks() { |
| PendingReadRequest request; |
| while ((request = pendingReads.peek()) != null) { |
| if (!request.isDone) { |
| break; |
| } |
| pendingReads.remove(); |
| request.complete(readEntryListener); |
| } |
| if (pendingReads.isEmpty()) { |
| done.countDown(); |
| } |
| } |
| |
| @Override |
| public void run() { |
| try { |
| done.await(); |
| } catch (InterruptedException e) { |
| logger.info("Interrupted on stream reading ledger {} : ", lh.getId(), e); |
| } |
| } |
| } |