io.netty.channel.DefaultFileRegion Maven / Gradle / Ivy
/*
* Copyright 2012 The Netty Project
*
* The Netty Project 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.AbstractReferenceCounted;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.io.IOException;
import java.nio.channels.FileChannel;
import java.nio.channels.WritableByteChannel;
/**
* Default {@link FileRegion} implementation which transfer data from a {@link FileChannel}.
*/
public class DefaultFileRegion extends AbstractReferenceCounted implements FileRegion {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(DefaultFileRegion.class);
private final FileChannel file;
private final long position;
private final long count;
/**
* Create a new instance
*
* @param file the {@link FileChannel} which should be transfered
* @param position the position from which the transfer should start
* @param count the number of bytes to transfer
*/
public DefaultFileRegion(FileChannel file, long position, long count) {
if (file == null) {
throw new NullPointerException("file");
}
if (position < 0) {
throw new IllegalArgumentException("position must be >= 0 but was " + position);
}
if (count <= 0) {
throw new IllegalArgumentException("count must be >= 0 but was " + count);
}
this.file = file;
this.position = position;
this.count = count;
}
@Override
public long position() {
return position;
}
@Override
public long count() {
return count;
}
@Override
public long transferTo(WritableByteChannel target, long position) throws IOException {
long count = this.count - position;
if (count < 0 || position < 0) {
throw new IllegalArgumentException(
"position out of range: " + position +
" (expected: 0 - " + (this.count - 1) + ')');
}
if (count == 0) {
return 0L;
}
return file.transferTo(this.position + position, count, target);
}
@Override
protected void deallocate() {
try {
file.close();
} catch (IOException e) {
if (logger.isWarnEnabled()) {
logger.warn("Failed to close a file.", e);
}
}
}
}