netty5/example/src/main/java/io/netty/example/factorial/FactorialServerHandler.java
Trustin Lee 223efc5f99 Clean up the examples
Motivation:

The examples have not been updated since long time ago, showing various
issues fixed in this commit.

Modifications:

- Overall simplification to reduce LoC
  - Use system properties to get options instead of parsing args.
  - Minimize option validation
  - Just use System.out/err instead of Logger
  - Do not pass config as parameters - just access it directly
  - Move the main logic to main(String[]) instead of creating a new
    instance meaninglessly
    - Update netty-build-21 to make checkstyle not complain
  - Remove 'throws Exception' clause if possible
- Line wrap at 120 (previously at 80)
- Add an option to enable SSL for most examples
- Use ChannelFuture.sync() instead of await()
- Use System.out for the actual result. Use System.err otherwise.
- Delete examples that are not very useful:
  - applet
  - websocket/html5
  - websocketx/sslserver
  - localecho/multithreaded
- Add run-example.sh which simplifies launching an example from command
  line
- Rewrite FileServer example

Result:

Shorter and simpler examples.  A user can focus more on what it actually
does than miscellaneous stuff.  A user can launch an example very
easily.
2014-05-23 17:13:09 +09:00

54 lines
2.0 KiB
Java

/*
* Copyright 2012 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.factorial;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import java.math.BigInteger;
/**
* Handler for a server-side channel. This handler maintains stateful
* information which is specific to a certain channel using member variables.
* Therefore, an instance of this handler can cover only one channel. You have
* to create a new handler instance whenever you create a new channel and insert
* this handler to avoid a race condition.
*/
public class FactorialServerHandler extends SimpleChannelInboundHandler<BigInteger> {
private BigInteger lastMultiplier = new BigInteger("1");
private BigInteger factorial = new BigInteger("1");
@Override
public void channelRead0(ChannelHandlerContext ctx, BigInteger msg) throws Exception {
// Calculate the cumulative factorial and send it to the client.
lastMultiplier = msg;
factorial = factorial.multiply(msg);
ctx.writeAndFlush(factorial);
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
System.err.printf("Factorial of %,d is: %,d%n", lastMultiplier, factorial);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}