netty5/src/main/java/io/netty/channel/ReceiveBufferSizePredictor.java
2011-12-09 12:46:59 +09:00

56 lines
2.0 KiB
Java

/*
* Copyright 2009 Red Hat, Inc.
*
* Red Hat 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 io.netty.channel;
import io.netty.buffer.ChannelBuffer;
/**
* Predicts the number of readable bytes in the receive buffer of a
* {@link Channel}.
* <p>
* It calculates the close-to-optimal capacity of the {@link ChannelBuffer}
* for the next read operation depending on the actual number of read bytes
* in the previous read operation. More accurate the prediction is, more
* effective the memory utilization will be.
* <p>
* Once a read operation is performed and the actual number of read bytes is
* known, an I/O thread will call {@link #previousReceiveBufferSize(int)} to
* update the predictor so it can predict more accurately next time.
*
* @author <a href="http://netty.io/">The Netty Project</a>
* @author <a href="http://gleamynode.net/">Trustin Lee</a>
*/
public interface ReceiveBufferSizePredictor {
/**
* Predicts the capacity of the {@link ChannelBuffer} for the next
* read operation depending on the actual number of read bytes in the
* previous read operation.
*
* @return the expected number of readable bytes this time
*/
int nextReceiveBufferSize();
/**
* Updates this predictor by specifying the actual number of read bytes
* in the previous read operation.
*
* @param previousReceiveBufferSize
* the actual number of read bytes in the previous read operation
*/
void previousReceiveBufferSize(int previousReceiveBufferSize);
}