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 org.apache.tinkerpop.gremlin.driver.handler; import org.apache.tinkerpop.gremlin.driver.MessageSerializer; import org.apache.tinkerpop.gremlin.driver.message.RequestMessage; import org.apache.tinkerpop.gremlin.driver.ser.MessageTextSerializer; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.MessageToByteEncoder; import io.netty.util.CharsetUtil; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * @author Stephen Mallette (http://stephen.genoprime.com) */ public final class NioGremlinRequestEncoder extends MessageToByteEncoder<Object> { private static final Logger logger = LoggerFactory.getLogger(WebSocketGremlinRequestEncoder.class); private boolean binaryEncoding = false; private final MessageSerializer serializer; public NioGremlinRequestEncoder(final boolean binaryEncoding, final MessageSerializer serializer) { this.binaryEncoding = binaryEncoding; this.serializer = serializer; } @Override protected void encode(final ChannelHandlerContext channelHandlerContext, final Object msg, final ByteBuf byteBuf) throws Exception { final RequestMessage requestMessage = (RequestMessage) msg; try { if (binaryEncoding) { // wrap the serialized message/payload inside of a "frame". this works around the problem where // the length of the payload is not encoded into the general protocol. that length isn't needed // for websockets because under that protocol, the message is wrapped in a "websocket frame". this // is not the optimal way to deal with this really, but it does prevent a protocol change in this // immediate moment trying to get the NioChannelizer working. final ByteBuf bytes = serializer.serializeRequestAsBinary(requestMessage, channelHandlerContext.alloc()); byteBuf.writeInt(bytes.capacity()); byteBuf.writeBytes(bytes); } else { final MessageTextSerializer textSerializer = (MessageTextSerializer) serializer; final byte[] bytes = textSerializer.serializeRequestAsString(requestMessage) .getBytes(CharsetUtil.UTF_8); byteBuf.writeInt(bytes.length); byteBuf.writeBytes(bytes); } } catch (Exception ex) { logger.warn(String.format( "An error occurred during serialization of this request [%s] - it could not be sent to the server.", requestMessage), ex); } } }