Java tutorial
/* * Copyright 2015 Kevin Herron * * Licensed 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.digitalpetri.opcua.stack.core.channel.headers; import com.digitalpetri.opcua.stack.core.channel.messages.TcpMessageEncoder; import com.google.common.primitives.Ints; import io.netty.buffer.ByteBuf; public interface HeaderDecoder { long PROTOCOL_VERSION = 0L; int HEADER_LENGTH = 8; int HEADER_LENGTH_INDEX = 4; /** * Get the message length from a {@link ByteBuf} containing a {@link TcpMessageEncoder}. The reader index will not be * advanced. * * @param buffer {@link ByteBuf} to extract from. * @return The message length, which includes the size of the header. */ default int getMessageLength(ByteBuf buffer) { return Ints.checkedCast(buffer.getUnsignedInt(buffer.readerIndex() + HEADER_LENGTH_INDEX)); } }