| /** |
| * 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.policy; |
| |
| import org.apache.activemq.broker.region.MessageReference; |
| |
| import java.io.IOException; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.LinkedList; |
| import java.util.List; |
| |
| /** |
| * An eviction strategy which evicts the oldest message within messages with the same property value |
| * |
| * |
| * @org.apache.xbean.XBean |
| * |
| */ |
| public class UniquePropertyMessageEvictionStrategy extends MessageEvictionStrategySupport { |
| |
| protected String propertyName; |
| |
| public String getPropertyName() { |
| return propertyName; |
| } |
| |
| public void setPropertyName(String propertyName) { |
| this.propertyName = propertyName; |
| } |
| |
| @Override |
| public MessageReference[] evictMessages(LinkedList messages) throws IOException { |
| List<MessageReference> messageReferences = new LinkedList<>(messages); |
| HashMap<Object, MessageReference> pivots = new HashMap<>(); |
| |
| for (MessageReference reference : messageReferences) { |
| if (propertyName != null && reference.getMessage().getProperty(propertyName) != null) { |
| Object key = reference.getMessage().getProperty(propertyName); |
| if (pivots.containsKey(key)) { |
| MessageReference pivot = pivots.get(key); |
| if (reference.getMessage().getTimestamp() > pivot.getMessage().getTimestamp()) { |
| pivots.put(key, reference); |
| } |
| } else { |
| pivots.put(key, reference); |
| } |
| } |
| } |
| |
| if (pivots.isEmpty() || pivots.values().size() == messageReferences.size()) { |
| return new MessageReference[]{(MessageReference) messages.removeFirst()}; |
| } else { |
| messages.removeIf(message -> !pivots.containsValue(message)); |
| messageReferences.removeAll(pivots.values()); |
| return messageReferences.toArray(new MessageReference[0]); |
| } |
| } |
| |
| } |