org.xnio.channels.BlockingReadableByteChannel Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* JBoss, Home of Professional Open Source
*
* Copyright 2009 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 static org.xnio._private.Messages.msg;
import java.nio.channels.ScatteringByteChannel;
import java.nio.ByteBuffer;
import java.io.IOException;
import java.util.concurrent.TimeUnit;
import org.xnio.Buffers;
/**
* A blocking wrapper for a {@code StreamSourceChannel}. Read operations will block until some data may be transferred.
* Once any amount of data is read, the operation will return. If a read timeout is specified, then the read methods
* will throw a {@link ReadTimeoutException} if the timeout expires without reading any data.
*/
public class BlockingReadableByteChannel implements ScatteringByteChannel {
private final StreamSourceChannel delegate;
private volatile long readTimeout;
/**
* Construct a new instance.
*
* @param delegate the channel to forward I/O operations to
*/
public BlockingReadableByteChannel(final StreamSourceChannel delegate) {
this.delegate = delegate;
}
/**
* Construct a new instance.
*
* @param delegate the channel to forward I/O operations to
* @param readTimeout the read timeout
* @param readTimeoutUnit the read timeout unit
*/
public BlockingReadableByteChannel(final StreamSourceChannel delegate, final long readTimeout, final TimeUnit readTimeoutUnit) {
if (readTimeout < 0L) {
throw msg.parameterOutOfRange("readTimeout");
}
this.delegate = delegate;
final long calcTimeout = readTimeoutUnit.toNanos(readTimeout);
this.readTimeout = readTimeout == 0L ? 0L : calcTimeout < 1L ? 1L : calcTimeout;
}
/**
* Set the read timeout.
*
* @param readTimeout the read timeout
* @param readTimeoutUnit the read timeout unit
*/
public void setReadTimeout(long readTimeout, TimeUnit readTimeoutUnit) {
if (readTimeout < 0L) {
throw msg.parameterOutOfRange("readTimeout");
}
final long calcTimeout = readTimeoutUnit.toNanos(readTimeout);
this.readTimeout = readTimeout == 0L ? 0L : calcTimeout < 1L ? 1L : calcTimeout;
}
/**
* Perform a blocking, scattering read operation.
*
* @param dsts the destination buffers
* @param offset the offset into the destination buffer array
* @param length the number of buffers to read into
* @return the number of bytes actually read (will be greater than zero)
* @throws IOException if an I/O error occurs
*/
public long read(final ByteBuffer[] dsts, final int offset, final int length) throws IOException {
if (!Buffers.hasRemaining(dsts, offset, length)) {
return 0L;
}
final StreamSourceChannel delegate = this.delegate;
long res;
if ((res = delegate.read(dsts, offset, length)) == 0L) {
long start = System.nanoTime();
long elapsed = 0L, readTimeout;
do {
readTimeout = this.readTimeout;
if (readTimeout == 0L || readTimeout == Long.MAX_VALUE) {
delegate.awaitReadable();
} else if (readTimeout <= elapsed) {
throw msg.readTimeout();
} else {
delegate.awaitReadable(readTimeout - elapsed, TimeUnit.NANOSECONDS);
}
elapsed = System.nanoTime() - start;
} while ((res = delegate.read(dsts, offset, length)) == 0L);
}
return res;
}
/**
* Perform a blocking, scattering read operation.
*
* @param dsts the destination buffers
* @return the number of bytes actually read (will be greater than zero)
* @throws IOException if an I/O error occurs
*/
public long read(final ByteBuffer[] dsts) throws IOException {
return read(dsts, 0, dsts.length);
}
/**
* Perform a blocking read operation.
*
* @param dst the destination buffer
* @return the number of bytes actually read (will be greater than zero)
* @throws IOException if an I/O error occurs
*/
public int read(final ByteBuffer dst) throws IOException {
if (! dst.hasRemaining()) {
return 0;
}
final StreamSourceChannel delegate = this.delegate;
int res;
if ((res = delegate.read(dst)) == 0) {
long start = System.nanoTime();
long elapsed = 0L, readTimeout;
do {
readTimeout = this.readTimeout;
if (readTimeout == 0L || readTimeout == Long.MAX_VALUE) {
delegate.awaitReadable();
} else if (readTimeout <= elapsed) {
throw msg.readTimeout();
} else {
delegate.awaitReadable(readTimeout - elapsed, TimeUnit.NANOSECONDS);
}
elapsed = System.nanoTime() - start;
} while ((res = delegate.read(dst)) == 0);
}
return res;
}
/** {@inheritDoc} */
public boolean isOpen() {
return delegate.isOpen();
}
/** {@inheritDoc} */
public void close() throws IOException {
delegate.close();
}
}