001/* 002 * (C) Copyright 2017 Nuxeo SA (http://nuxeo.com/) and others. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 * 016 * Contributors: 017 * bdelbosc 018 */ 019package org.nuxeo.ecm.platform.importer.mqueues.mqueues; 020 021import java.io.Externalizable; 022import java.time.Duration; 023import java.util.Objects; 024 025/** 026 * An appender is used to append message into a MQueue. 027 * Implementations must be thread safe. 028 * 029 * @since 9.2 030 */ 031public interface MQAppender<M extends Externalizable> extends AutoCloseable { 032 033 /** 034 * Returns the MQueue's name. 035 */ 036 String name(); 037 038 /** 039 * Returns the number of partitions. 040 */ 041 int size(); 042 043 /** 044 * Append a message into a partition, returns {@link MQOffset} position of the message. 045 * 046 * This method is thread safe, a queue can be shared by multiple producers. 047 * 048 * @param partition index lower than {@link #size()} 049 */ 050 MQOffset append(int partition, M message); 051 052 /** 053 * Same as {@link #append(int, Externalizable)}, the queue is chosen using a hash of {@param key}. 054 */ 055 default MQOffset append(String key, M message) { 056 Objects.requireNonNull(key); 057 // Provide a basic partitioning that works because: 058 // 1. String.hashCode is known to be constant even with different JVM (this is not the case for all objects) 059 // 2. the modulo operator is not optimal when rebalancing on partitions resizing but this should not happen. 060 // and yes hashCode can be negative. 061 int queue = (key.hashCode() & 0x7fffffff) % size(); 062 return append(queue, message); 063 } 064 065 /** 066 * Wait for consumer to process a message up to the offset. 067 * 068 * The message is processed if a consumer commit its offset (or a bigger one) in the group name space. 069 * 070 * Return {@code true} if the message has been consumed, {@code false} in case of timeout. 071 */ 072 boolean waitFor(MQOffset offset, String group, Duration timeout) throws InterruptedException; 073 074 /** 075 * Returns {@code true} if the close has been closed. 076 */ 077 boolean closed(); 078}