| /** |
| * 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 org.apache.activemq.broker.region.group; |
| |
| import org.apache.activemq.command.ConsumerId; |
| |
| /** |
| * Uses hash-code buckets to associate consumers with sets of message group IDs. |
| * |
| * |
| */ |
| public class MessageGroupHashBucket implements MessageGroupMap { |
| |
| private final int bucketCount; |
| private final ConsumerId[] consumers; |
| |
| public MessageGroupHashBucket(int bucketCount) { |
| this.bucketCount = bucketCount; |
| this.consumers = new ConsumerId[bucketCount]; |
| } |
| |
| public void put(String groupId, ConsumerId consumerId) { |
| int bucket = getBucketNumber(groupId); |
| consumers[bucket] = consumerId; |
| } |
| |
| public ConsumerId get(String groupId) { |
| int bucket = getBucketNumber(groupId); |
| return consumers[bucket]; |
| } |
| |
| public ConsumerId removeGroup(String groupId) { |
| int bucket = getBucketNumber(groupId); |
| ConsumerId answer = consumers[bucket]; |
| consumers[bucket] = null; |
| return answer; |
| } |
| |
| public MessageGroupSet removeConsumer(ConsumerId consumerId) { |
| MessageGroupSet answer = null; |
| for (int i = 0; i < consumers.length; i++) { |
| ConsumerId owner = consumers[i]; |
| if (owner != null && owner.equals(consumerId)) { |
| answer = createMessageGroupSet(i, answer); |
| consumers[i] = null; |
| } |
| } |
| if (answer == null) { |
| // make an empty set |
| answer = EmptyMessageGroupSet.INSTANCE; |
| } |
| return answer; |
| } |
| |
| public String toString() { |
| int count = 0; |
| for (int i = 0; i < consumers.length; i++) { |
| if (consumers[i] != null) { |
| count++; |
| } |
| } |
| return "active message group buckets: " + count; |
| } |
| |
| protected MessageGroupSet createMessageGroupSet(int bucketNumber, final MessageGroupSet parent) { |
| final MessageGroupSet answer = createMessageGroupSet(bucketNumber); |
| if (parent == null) { |
| return answer; |
| } else { |
| // union the two sets together |
| return new MessageGroupSet() { |
| public boolean contains(String groupID) { |
| return parent.contains(groupID) || answer.contains(groupID); |
| } |
| }; |
| } |
| } |
| |
| protected MessageGroupSet createMessageGroupSet(final int bucketNumber) { |
| return new MessageGroupSet() { |
| public boolean contains(String groupID) { |
| int bucket = getBucketNumber(groupID); |
| return bucket == bucketNumber; |
| } |
| }; |
| } |
| |
| protected int getBucketNumber(String groupId) { |
| int bucket = groupId.hashCode() % bucketCount; |
| // bucket could be negative |
| if (bucket < 0) { |
| bucket *= -1; |
| } |
| return bucket; |
| } |
| } |