gremlin-server/src/main/java/org/apache/tinkerpop/gremlin/server/handler/WsGremlinResponseFrameEncoder.java

/*
 * 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 io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageEncoder;
import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;

import java.util.List;

/**
 * Encodes {@code ByteBuf} and {@code String} values to Websocket frames.
 *
 * @author Stephen Mallette (http://stephen.genoprime.com)
 */
@ChannelHandler.Sharable
public class WsGremlinResponseFrameEncoder extends MessageToMessageEncoder<Frame> {
    @Override
    protected void encode(final ChannelHandlerContext ctx, final Frame o, final List<Object> objects) throws Exception {
        if (o.getMsg() instanceof ByteBuf)
            objects.add(new BinaryWebSocketFrame((ByteBuf) o.getMsg()));
        else if (o.getMsg() instanceof String)
            objects.add(new TextWebSocketFrame(true, 0, o.getMsg().toString()));
    }
}