/*
* ====================================================================
* 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
* <http://www.apache.org/>.
*
*/
package org.apache.http.nio.client.methods;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.FileEntity;
import org.apache.http.nio.ContentDecoder;
import org.apache.http.nio.ContentDecoderChannel;
import org.apache.http.nio.FileContentDecoder;
import org.apache.http.nio.IOControl;
import org.apache.http.nio.protocol.AbstractAsyncResponseConsumer;
import org.apache.http.protocol.HttpContext;
import org.apache.http.util.Asserts;
/**
* {@link org.apache.http.nio.protocol.HttpAsyncResponseConsumer} implementation that
* streams content entity enclosed in an HTTP response directly into a file
* without an intermediate in-memory buffer.
* <p/>
* This consumer can be useful for file downloads.
*
* @since 4.0
*/
public abstract class ZeroCopyConsumer<T> extends AbstractAsyncResponseConsumer<T> {
private final File file;
private final RandomAccessFile accessfile;
private HttpResponse response;
private ContentType contentType;
private FileChannel fileChannel;
private long idx = -1;
public ZeroCopyConsumer(final File file) throws FileNotFoundException {
super();
if (file == null) {
throw new IllegalArgumentException("File may nor be null");
}
this.file = file;
this.accessfile = new RandomAccessFile(this.file, "rw");
}
@Override
protected void onResponseReceived(final HttpResponse response) {
this.response = response;
}
@Override
protected void onEntityEnclosed(
final HttpEntity entity, final ContentType contentType) throws IOException {
this.contentType = contentType;
this.fileChannel = this.accessfile.getChannel();
this.idx = 0;
}
@Override
protected void onContentReceived(
final ContentDecoder decoder, final IOControl ioctrl) throws IOException {
Asserts.notNull(this.fileChannel, "File channel");
final long transferred;
if (decoder instanceof FileContentDecoder) {
transferred = ((FileContentDecoder)decoder).transfer(
this.fileChannel, this.idx, Integer.MAX_VALUE);
} else {
transferred = this.fileChannel.transferFrom(
new ContentDecoderChannel(decoder), this.idx, Integer.MAX_VALUE);
}
if (transferred > 0) {
this.idx += transferred;
}
if (decoder.isCompleted()) {
this.fileChannel.close();
}
}
/**
* Invoked to process received file.
*
* @param response original response head.
* @param file file containing response content.
* @param contentType the cotnent type.
* @return result of the response processing
*/
protected abstract T process(
HttpResponse response, File file, ContentType contentType) throws Exception;
@Override
protected T buildResult(final HttpContext context) throws Exception {
this.response.setEntity(new FileEntity(this.file, this.contentType));
return process(this.response, this.file, this.contentType);
}
@Override
protected void releaseResources() {
try {
this.accessfile.close();
} catch (final IOException ignore) {
}
}
}