001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package org.apache.activemq.memory.buffer; 019 020/** 021 * Represents a collection of MessageQueue instances which are all bound by the 022 * same memory buffer to fix the amount of RAM used to some uppper bound. 023 * 024 * 025 */ 026public interface MessageBuffer { 027 028 int getSize(); 029 030 /** 031 * Creates a new message queue instance 032 */ 033 MessageQueue createMessageQueue(); 034 035 /** 036 * After a message queue has changed we may need to perform some evictions 037 * 038 * @param delta 039 * @param queueSize 040 */ 041 void onSizeChanged(MessageQueue queue, int delta, int queueSize); 042 043 void clear(); 044 045}