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.carbondata.core.dictionary.server; import org.apache.carbondata.common.logging.LogServiceFactory; import org.apache.carbondata.core.dictionary.generator.ServerDictionaryGenerator; import org.apache.carbondata.core.dictionary.generator.key.DictionaryMessage; import org.apache.carbondata.core.metadata.schema.table.CarbonTable; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; import org.apache.log4j.Logger; /** * Handler for Dictionary server. */ @ChannelHandler.Sharable public class NonSecureDictionaryServerHandler extends ChannelInboundHandlerAdapter { private static final Logger LOGGER = LogServiceFactory .getLogService(NonSecureDictionaryServerHandler.class.getName()); /** * dictionary generator */ private ServerDictionaryGenerator generatorForServer = new ServerDictionaryGenerator(); /** * channel registered * * @param ctx * @throws Exception */ public void channelActive(ChannelHandlerContext ctx) throws Exception { LOGGER.info("Connected " + ctx); super.channelActive(ctx); } @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { try { ByteBuf data = (ByteBuf) msg; DictionaryMessage key = new DictionaryMessage(); key.readSkipLength(data); data.release(); int outPut = processMessage(key); key.setDictionaryValue(outPut); // Send back the response ByteBuf buffer = ctx.alloc().buffer(); key.writeData(buffer); ctx.writeAndFlush(buffer); } catch (Exception e) { LOGGER.error(e); throw e; } } /** * handle exceptions * * @param ctx * @param cause */ @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { LOGGER.error("exceptionCaught", cause); ctx.close(); } /** * process message by message type * * @param key * @return * @throws Exception */ public int processMessage(DictionaryMessage key) throws Exception { switch (key.getType()) { case DICT_GENERATION: generatorForServer.initializeGeneratorForColumn(key); return generatorForServer.generateKey(key); case SIZE: generatorForServer.initializeGeneratorForColumn(key); return generatorForServer.size(key); case WRITE_TABLE_DICTIONARY: generatorForServer.writeTableDictionaryData(key.getTableUniqueId()); return 0; default: return -1; } } void initializeTable(CarbonTable carbonTable) { generatorForServer.initializeGeneratorForTable(carbonTable); } }