org.xnio.channels.StreamSourceChannel Maven / Gradle / Ivy
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/*
* JBoss, Home of Professional Open Source
*
* Copyright 2008 Red Hat, Inc. and/or its affiliates.
*
* Licensed 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.xnio.channels;
import java.nio.ByteBuffer;
import java.nio.channels.ScatteringByteChannel;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.FileChannel;
import java.io.IOException;
import org.xnio.ChannelListener;
/**
* A stream source channel. This type of channel is a readable source for bytes. While all channel types are
* thread-safe, reading a stream from more than one thread concurrently will cause data corruption and may be
* disallowed at the option of the implementation.
*/
public interface StreamSourceChannel extends ReadableByteChannel, ScatteringByteChannel, SuspendableReadChannel {
/**
* Transfers bytes into the given file from this channel. Using this method in preference to {@link FileChannel#transferFrom(ReadableByteChannel, long, long)}
* may provide a performance advantage on some platforms.
*
* If the current thread is interrupted when this method is called, it may throw a {@link java.io.InterruptedIOException};
* however, if this exception is thrown, the {@link java.io.InterruptedIOException#bytesTransferred} field is
* guaranteed to be 0.
*
* @param position the position within the file from which the transfer is to begin
* @param count the number of bytes to be transferred
* @param target the file to write to
* @return the number of bytes (possibly 0) that were actually transferred
* @throws IOException if an I/O error occurs
*/
long transferTo(long position, long count, FileChannel target) throws IOException;
/**
* Transfers bytes into the given channel target. On some platforms, this may avoid copying bytes between user
* and kernel space. On other platforms, bytes are passed through the {@code throughBuffer} parameter's buffer
* space. On entry, {@code throughBuffer} will be cleared. On exit, the buffer will be
* flipped for emptying, and may possibly be empty or may contain data. If this method returns a value less than
* {@code count}, then the remaining data in {@code throughBuffer} may contain data read from this channel which must
* be written to {@code target} to complete the operation. Note that using a direct buffer may provide an
* intermediate performance gain on platforms without zero-copy facilities.
*
* If the current thread is interrupted when this method is called, it may throw a {@link java.io.InterruptedIOException};
* however, if this exception is thrown, the {@link java.io.InterruptedIOException#bytesTransferred} field is
* guaranteed to be 0.
*
* Note that the return value is the amount of data that was actually transferred to the {@link StreamSinkChannel}.
* The actual amount of data read could be larger than this, and can be calculated by adding the return value and
* the amount of data left in {@code throughBuffer}.
*
* @param count the number of bytes to be transferred
* @param throughBuffer the buffer to copy through.
* @param target the destination to write to
* @return the number of bytes (possibly 0) that were actually transferred, or -1 if the end of input was reached
* @throws IOException if an I/O error occurs
*/
long transferTo(long count, ByteBuffer throughBuffer, StreamSinkChannel target) throws IOException;
/** {@inheritDoc} */
ChannelListener.Setter getReadSetter();
/** {@inheritDoc} */
ChannelListener.Setter getCloseSetter();
}