Java tutorial
/* * Copyright (c) 2015 AsyncHttpClient Project. All rights reserved. * * This program is licensed to you under the Apache License Version 2.0, * and you may not use this file except in compliance with the Apache License Version 2.0. * You may obtain a copy of the Apache License Version 2.0 at * http://www.apache.org/licenses/LICENSE-2.0. * * Unless required by applicable law or agreed to in writing, * software distributed under the Apache License Version 2.0 is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the Apache License Version 2.0 for the specific language governing permissions and limitations there under. */ package org.asynchttpclient.request.body.multipart.part; import static org.asynchttpclient.request.body.multipart.Part.*; import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBufAllocator; import io.netty.buffer.Unpooled; import java.io.IOException; import java.nio.channels.WritableByteChannel; import org.asynchttpclient.request.body.multipart.FileLikePart; public class MessageEndMultipartPart extends MultipartPart<FileLikePart> { // lazy private ByteBuf contentBuffer; public MessageEndMultipartPart(byte[] boundary) { super(null, boundary); state = MultipartState.PRE_CONTENT; } @Override public long transferTo(ByteBuf target) throws IOException { return transfer(lazyLoadContentBuffer(), target, MultipartState.DONE); } @Override public long transferTo(WritableByteChannel target) throws IOException { slowTarget = false; return transfer(lazyLoadContentBuffer(), target, MultipartState.DONE); } private ByteBuf lazyLoadContentBuffer() { if (contentBuffer == null) { contentBuffer = ByteBufAllocator.DEFAULT.buffer((int) getContentLength()); contentBuffer.writeBytes(EXTRA_BYTES).writeBytes(boundary).writeBytes(EXTRA_BYTES) .writeBytes(CRLF_BYTES); } return contentBuffer; } @Override protected int computePreContentLength() { return 0; } @Override protected ByteBuf computePreContentBytes(int preContentLength) { return Unpooled.EMPTY_BUFFER; } @Override protected int computePostContentLength() { return 0; } @Override protected ByteBuf computePostContentBytes(int postContentLength) { return Unpooled.EMPTY_BUFFER; } @Override protected long getContentLength() { return EXTRA_BYTES.length + boundary.length + EXTRA_BYTES.length + CRLF_BYTES.length; } @Override protected long transferContentTo(ByteBuf target) throws IOException { throw new UnsupportedOperationException("Not supposed to be called"); } @Override protected long transferContentTo(WritableByteChannel target) throws IOException { throw new UnsupportedOperationException("Not supposed to be called"); } @Override public void close() { super.close(); if (contentBuffer != null) contentBuffer.release(); } }