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Java example source code file (MemcacheClientHandler.java)

This example Java source code file (MemcacheClientHandler.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

binarymemcacherequest, bytebuf, channelpromise, defaultbinarymemcacherequest, defaultfullbinarymemcacherequest, fullbinarymemcacheresponse, illegalargumentexception, illegalstateexception, malformed, object, override, string, throwable, unknown

The MemcacheClientHandler.java Java example source code

/*
 * Copyright 2014 The Netty Project
 *
 * The Netty Project 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 io.netty.example.memcache.binary;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.handler.codec.memcache.binary.BinaryMemcacheOpcodes;
import io.netty.handler.codec.memcache.binary.BinaryMemcacheRequest;
import io.netty.handler.codec.memcache.binary.DefaultBinaryMemcacheRequest;
import io.netty.handler.codec.memcache.binary.DefaultFullBinaryMemcacheRequest;
import io.netty.handler.codec.memcache.binary.FullBinaryMemcacheResponse;
import io.netty.util.CharsetUtil;

public class MemcacheClientHandler extends ChannelDuplexHandler {

    /**
     * Transforms basic string requests to binary memcache requests
     */
    @Override
    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
        String command = (String) msg;
        if (command.startsWith("get ")) {
            String keyString = command.substring("get ".length());
            ByteBuf key = Unpooled.wrappedBuffer(keyString.getBytes(CharsetUtil.UTF_8));

            BinaryMemcacheRequest req = new DefaultBinaryMemcacheRequest(key);
            req.setOpcode(BinaryMemcacheOpcodes.GET);

            ctx.write(req, promise);
        } else if (command.startsWith("set ")) {
            String[] parts = command.split(" ", 3);
            if (parts.length < 3) {
                throw new IllegalArgumentException("Malformed Command: " + command);
            }
            String keyString = parts[1];
            String value = parts[2];

            ByteBuf key = Unpooled.wrappedBuffer(keyString.getBytes(CharsetUtil.UTF_8));
            ByteBuf content = Unpooled.wrappedBuffer(value.getBytes(CharsetUtil.UTF_8));
            ByteBuf extras = ctx.alloc().buffer(8);
            extras.writeZero(8);

            BinaryMemcacheRequest req = new DefaultFullBinaryMemcacheRequest(key, extras, content);
            req.setOpcode(BinaryMemcacheOpcodes.SET);

            ctx.write(req, promise);
        } else {
            throw new IllegalStateException("Unknown Message: " + msg);
        }
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        FullBinaryMemcacheResponse res = (FullBinaryMemcacheResponse) msg;
        System.out.println(res.content().toString(CharsetUtil.UTF_8));
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }
}

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