org.apache.kafka.common.network.TransferableChannel Maven / Gradle / Ivy
/*
* 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.kafka.common.network;
import java.io.IOException;
import java.nio.channels.FileChannel;
import java.nio.channels.GatheringByteChannel;
/**
* Extends GatheringByteChannel with the minimal set of methods required by the Send interface. Supporting TLS and
* efficient zero copy transfers are the main reasons for the additional methods.
*
* @see SslTransportLayer
*/
public interface TransferableChannel extends GatheringByteChannel {
/**
* @return true if there are any pending writes. false if the implementation directly write all data to output.
*/
boolean hasPendingWrites();
/**
* Transfers bytes from `fileChannel` to this `TransferableChannel`.
*
* This method will delegate to {@link FileChannel#transferTo(long, long, java.nio.channels.WritableByteChannel)},
* but it will unwrap the destination channel, if possible, in order to benefit from zero copy. This is required
* because the fast path of `transferTo` is only executed if the destination buffer inherits from an internal JDK
* class.
*
* @param fileChannel The source channel
* @param position The position within the file at which the transfer is to begin; must be non-negative
* @param count The maximum number of bytes to be transferred; must be non-negative
* @return The number of bytes, possibly zero, that were actually transferred
* @see FileChannel#transferTo(long, long, java.nio.channels.WritableByteChannel)
*/
long transferFrom(FileChannel fileChannel, long position, long count) throws IOException;
}