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Apache HttpComponents Core (non-blocking I/O)
/*
* ====================================================================
* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* .
*
*/
package org.apache.http.impl.nio.codecs;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.WritableByteChannel;
import org.apache.http.impl.io.HttpTransportMetricsImpl;
import org.apache.http.nio.ContentEncoder;
import org.apache.http.nio.reactor.SessionOutputBuffer;
import org.apache.http.util.Args;
import org.apache.http.util.Asserts;
/**
* Abstract {@link ContentEncoder} that serves as a base for all content
* encoder implementations.
*
* @since 4.0
*/
public abstract class AbstractContentEncoder implements ContentEncoder {
protected final WritableByteChannel channel;
protected final SessionOutputBuffer buffer;
protected final HttpTransportMetricsImpl metrics;
/**
* TODO: make private
*/
protected boolean completed;
/**
* Creates an instance of this class.
*
* @param channel the destination channel.
* @param buffer the session output buffer that can be used to store
* session data for intermediate processing.
* @param metrics Transport metrics of the underlying HTTP transport.
*/
public AbstractContentEncoder(
final WritableByteChannel channel,
final SessionOutputBuffer buffer,
final HttpTransportMetricsImpl metrics) {
super();
Args.notNull(channel, "Channel");
Args.notNull(buffer, "Session input buffer");
Args.notNull(metrics, "Transport metrics");
this.buffer = buffer;
this.channel = channel;
this.metrics = metrics;
}
@Override
public boolean isCompleted() {
return this.completed;
}
@Override
public void complete() throws IOException {
this.completed = true;
}
protected void assertNotCompleted() {
Asserts.check(!this.completed, "Encoding process already completed");
}
/**
* Flushes content of the session buffer to the channel and updates transport metrics.
*
* @return number of bytes written to the channel.
*
* @since 4.3
*/
protected int flushToChannel() throws IOException {
if (!this.buffer.hasData()) {
return 0;
}
final int bytesWritten = this.buffer.flush(this.channel);
if (bytesWritten > 0) {
this.metrics.incrementBytesTransferred(bytesWritten);
}
return bytesWritten;
}
/**
* Flushes content of the given buffer to the channel and updates transport metrics.
*
* @return number of bytes written to the channel.
*
* @since 4.3
*/
protected int writeToChannel(final ByteBuffer src) throws IOException {
if (!src.hasRemaining()) {
return 0;
}
final int bytesWritten = this.channel.write(src);
if (bytesWritten > 0) {
this.metrics.incrementBytesTransferred(bytesWritten);
}
return bytesWritten;
}
/**
* Transfers content of the source to the channel and updates transport metrics.
*
* @param src source.
* @param limit max number of bytes to transfer.
* @return number of bytes transferred.
*
* @since 4.3
*/
protected int writeToChannel(final ByteBuffer src, final int limit) throws IOException {
return doWriteChunk(src, limit, true);
}
/**
* Transfers content of the source to the buffer and updates transport metrics.
*
* @param src source.
* @param limit max number of bytes to transfer.
* @return number of bytes transferred.
*
* @since 4.3
*/
protected int writeToBuffer(final ByteBuffer src, final int limit) throws IOException {
return doWriteChunk(src, limit, false);
}
private int doWriteChunk(
final ByteBuffer src, final int chunk, final boolean direct) throws IOException {
final int bytesWritten;
if (src.remaining() > chunk) {
final int oldLimit = src.limit();
final int newLimit = oldLimit - (src.remaining() - chunk);
src.limit(newLimit);
bytesWritten = doWriteChunk(src, direct);
src.limit(oldLimit);
} else {
bytesWritten = doWriteChunk(src, direct);
}
return bytesWritten;
}
private int doWriteChunk(final ByteBuffer src, final boolean direct) throws IOException {
if (direct) {
final int bytesWritten = this.channel.write(src);
if (bytesWritten > 0) {
this.metrics.incrementBytesTransferred(bytesWritten);
}
return bytesWritten;
} else {
final int chunk = src.remaining();
this.buffer.write(src);
return chunk;
}
}
}