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.server.handler; import com.codahale.metrics.Meter; import io.netty.util.CharsetUtil; import org.apache.tinkerpop.gremlin.driver.MessageSerializer; import org.apache.tinkerpop.gremlin.driver.message.ResponseMessage; import org.apache.tinkerpop.gremlin.driver.message.ResponseStatusCode; import org.apache.tinkerpop.gremlin.driver.ser.MessageTextSerializer; import org.apache.tinkerpop.gremlin.server.GremlinServer; import org.apache.tinkerpop.gremlin.server.util.MetricManager; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.MessageToByteEncoder; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import static com.codahale.metrics.MetricRegistry.name; /** * @author Stephen Mallette (http://stephen.genoprime.com) * @deprecated As of release 3.1.1-incubating, replaced by {@link NioGremlinResponseFrameEncoder} and * {@link GremlinResponseFrameEncoder} * @see <a href="https://issues.apache.org/jira/browse/TINKERPOP-1035">TINKERPOP-1035</a> */ @Deprecated @ChannelHandler.Sharable public class NioGremlinResponseEncoder extends MessageToByteEncoder<ResponseMessage> { private static final Logger logger = LoggerFactory.getLogger(NioGremlinResponseEncoder.class); static final Meter errorMeter = MetricManager.INSTANCE.getMeter(name(GremlinServer.class, "errors")); @Override protected void encode(final ChannelHandlerContext ctx, final ResponseMessage responseMessage, final ByteBuf byteBuf) throws Exception { final MessageSerializer serializer = ctx.channel().attr(StateKey.SERIALIZER).get(); final boolean useBinary = ctx.channel().attr(StateKey.USE_BINARY).get(); try { if (!responseMessage.getStatus().getCode().isSuccess()) errorMeter.mark(); if (useBinary) { final ByteBuf bytes = serializer.serializeResponseAsBinary(responseMessage, ctx.alloc()); byteBuf.writeInt(bytes.capacity()); byteBuf.writeBytes(bytes); bytes.release(); } else { // the expectation is that the GremlinTextRequestDecoder will have placed a MessageTextSerializer // instance on the channel. final MessageTextSerializer textSerializer = (MessageTextSerializer) serializer; final byte[] bytes = textSerializer.serializeResponseAsString(responseMessage) .getBytes(CharsetUtil.UTF_8); byteBuf.writeInt(bytes.length); byteBuf.writeBytes(bytes); } } catch (Exception ex) { errorMeter.mark(); logger.warn("The result [{}] in the request {} could not be serialized and returned.", responseMessage.getResult(), responseMessage.getRequestId(), ex); final String errorMessage = String.format("Error during serialization: %s", ex.getCause() != null ? ex.getCause().getMessage() : ex.getMessage()); final ResponseMessage error = ResponseMessage.build(responseMessage.getRequestId()) .statusMessage(errorMessage).code(ResponseStatusCode.SERVER_ERROR_SERIALIZATION).create(); if (useBinary) { final ByteBuf bytes = serializer.serializeResponseAsBinary(error, ctx.alloc()); byteBuf.writeInt(bytes.capacity()); byteBuf.writeBytes(bytes); bytes.release(); } else { final MessageTextSerializer textSerializer = (MessageTextSerializer) serializer; final byte[] bytes = textSerializer.serializeResponseAsString(error).getBytes(CharsetUtil.UTF_8); byteBuf.writeInt(bytes.length); byteBuf.writeBytes(bytes); } } } }