| /* |
| * 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. |
| */ |
| using System; |
| using System.Threading; |
| using Apache.NMS.Util; |
| |
| namespace Apache.NMS.ActiveMQ.Util |
| { |
| /// <summary> |
| /// Utility class for Tracking Memory Usage with an imposed limit on the amount |
| /// available. Provides methods for objects to wait on more space to become |
| /// available if the memory limit is reached. |
| /// </summary> |
| public class MemoryUsage |
| { |
| private readonly Atomic<bool> stopped = new Atomic<bool>(false); |
| private long limit = 0; |
| private long usage = 0; |
| private readonly object mutex = new object(); |
| |
| public MemoryUsage() |
| { |
| } |
| |
| public MemoryUsage( long limit ) |
| { |
| this.limit = limit; |
| } |
| |
| #region Property Accessors |
| |
| public long Limit |
| { |
| get { return limit; } |
| set { limit = value; } |
| } |
| |
| public long Usage |
| { |
| get { return usage; } |
| set { usage = value; } |
| } |
| |
| #endregion |
| |
| /// <summary> |
| /// If no space is available then this method blocks until more becomes available. |
| /// </summary> |
| public void WaitForSpace() |
| { |
| TimeSpan indefiniteWait = TimeSpan.FromMilliseconds(Timeout.Infinite); |
| this.WaitForSpace(indefiniteWait); |
| } |
| |
| /// <summary> |
| /// If no space is available then this method blocks until more becomes available |
| /// or until the specified timeout expires. |
| /// </summary> |
| /// <param name="timeout"> |
| /// A <see cref="System.TimeSpan"/> |
| /// </param> |
| public void WaitForSpace( TimeSpan timeout ) |
| { |
| lock(this.mutex) |
| { |
| while(this.IsFull() && !stopped.Value) |
| { |
| Tracer.Debug("MemoryUsage: Memory Limit Reached, waiting for more space."); |
| |
| if(!Monitor.Wait(this.mutex, timeout)) |
| { |
| return; |
| } |
| } |
| } |
| } |
| |
| /// <summary> |
| /// Attempts to increase the amount of Memory Used, if non is available to fill |
| /// then this method blocks until more is freed. |
| /// </summary> |
| /// <param name="usage"> |
| /// A <see cref="System.Int64"/> |
| /// </param> |
| public void EnqueueUsage( long usage ) |
| { |
| this.WaitForSpace(); |
| this.IncreaseUsage(usage); |
| } |
| |
| /// <summary> |
| /// Increase the level of Usage. |
| /// </summary> |
| /// <param name="value"> |
| /// A <see cref="System.Int64"/> |
| /// </param> |
| public void IncreaseUsage( long value ) |
| { |
| if(value == 0) |
| { |
| return; |
| } |
| |
| lock(this.mutex) |
| { |
| this.Usage += value; |
| |
| if(Tracer.IsDebugEnabled) |
| { |
| Tracer.DebugFormat("MemoryUsage: Increase Usage to: {0} bytes.", this.usage); |
| } |
| } |
| } |
| |
| /// <summary> |
| /// Decrease the level of Usage. |
| /// </summary> |
| /// <param name="value"> |
| /// A <see cref="System.Int64"/> |
| /// </param> |
| public void DecreaseUsage(long value) |
| { |
| if(value == 0) |
| { |
| return; |
| } |
| |
| lock(this.mutex) |
| { |
| if( value > this.Usage ) |
| { |
| this.Usage = 0; |
| } |
| else |
| { |
| this.Usage -= value; |
| } |
| |
| if(Tracer.IsDebugEnabled) |
| { |
| Tracer.DebugFormat("MemoryUsage: Decrease Usage to: {0} bytes.", this.usage); |
| } |
| |
| Monitor.PulseAll(this.mutex); |
| } |
| } |
| |
| /// <summary> |
| /// Checks if the Usage Windows has become full, is so returns true |
| /// otherwise returns false. |
| /// </summary> |
| /// <returns> |
| /// A <see cref="System.Boolean"/> |
| /// </returns> |
| public bool IsFull() |
| { |
| bool result = false; |
| |
| lock(this.mutex) |
| { |
| result = this.Usage >= this.Limit; |
| } |
| |
| return result; |
| } |
| |
| public void Stop() |
| { |
| this.stopped.Value = true; |
| lock(this.mutex) |
| { |
| Monitor.PulseAll(this.mutex); |
| } |
| } |
| } |
| } |