| /** |
| * 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; |
| |
| /** |
| * The position of an entry, identified by log segment sequence number and entry id. |
| */ |
| class EntryPosition { |
| |
| private long lssn; |
| private long entryId; |
| |
| EntryPosition(long lssn, long entryId) { |
| this.lssn = lssn; |
| this.entryId = entryId; |
| } |
| |
| public synchronized long getLogSegmentSequenceNumber() { |
| return lssn; |
| } |
| |
| public synchronized long getEntryId() { |
| return entryId; |
| } |
| |
| public synchronized boolean advance(long lssn, long entryId) { |
| if (lssn == this.lssn) { |
| if (entryId <= this.entryId) { |
| return false; |
| } |
| this.entryId = entryId; |
| return true; |
| } else if (lssn > this.lssn) { |
| this.lssn = lssn; |
| this.entryId = entryId; |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder sb = new StringBuilder(); |
| sb.append("(").append(lssn).append(", ").append(entryId).append(")"); |
| return sb.toString(); |
| } |
| } |