Java tutorial
/** * 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. */ package com.facebook.infrastructure.net.io; import org.apache.commons.lang.ArrayUtils; import java.nio.channels.SocketChannel; import java.nio.ByteBuffer; import java.io.IOException; /** * Author : Avinash Lakshman ( alakshman@facebook.com) & Prashant Malik ( pmalik@facebook.com ) */ public abstract class StartState { protected TcpReader stream_; public StartState(TcpReader stream) { stream_ = stream; } public abstract byte[] read() throws IOException, ReadNotCompleteException; public abstract void morphState() throws IOException; public abstract void setContextData(Object data); protected byte[] doRead(ByteBuffer buffer) throws IOException, ReadNotCompleteException { SocketChannel socketChannel = stream_.getStream(); int bytesRead = socketChannel.read(buffer); if (bytesRead == -1 && buffer.remaining() > 0) { throw new IOException("Reached an EOL or something bizzare occured. Reading from: " + socketChannel.socket().getInetAddress() + " BufferSizeRemaining: " + buffer.remaining()); } if (buffer.remaining() == 0) { morphState(); } else { throw new ReadNotCompleteException( "Specified number of bytes have not been read from the Socket Channel"); } return ArrayUtils.EMPTY_BYTE_ARRAY; } }