Neo Pan panlw

On Tue, Mar 12, 2013 at 1:26 PM, Martin Fowler [email protected] wrote:

The term pops up in some different places, so it's hard to know what it means without some context. In PoEAA I use the pattern Service Layer to represent a domain-oriented layer of behaviors that provide an API for the domain layer. This may or may not sit on top of a Domain Model. In DDD Eric Evans uses the term Service Object to refer to objects that represent processes (as opposed to Entities and Values). DDD Service Objects are often useful to factor out behavior that would otherwise bloat Entities, it's also a useful step to patterns like Strategy and Command.

It sounds like the DDD sense is the sense I'm encountering most often. I really need to read that book.

The conceptual problem I run into in a lot of codebases is that rather than representing a process, the "service objects" represent "a thing that does the process". Which sounds like a nitpicky difference, but it seems to have a real impact on how people us

	# Author: Pieter Noordhuis
	# Description: Simple demo to showcase Redis PubSub with EventMachine
	#
	# Update 7 Oct 2010:
	# - This example does not appear to work with Chrome >=6.0. Apparently,
	# the WebSocket protocol implementation in the cramp gem does not work
	# well with Chrome's (newer) WebSocket implementation.
	#
	# Requirements:
	# - rubygems: eventmachine, thin, cramp, sinatra, yajl-ruby

	// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
	// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating

	// requestAnimationFrame polyfill by Erik Möller. fixes from Paul Irish and Tino Zijdel

	// MIT license

	(function() {
	var lastTime = 0;
	var vendors = ['ms', 'moz', 'webkit', 'o'];

	#ack is a tool like grep, designed for programmers with large trees of heterogeneous source code

	#to install ack, see http://betterthangrep.com/
	#to use ack, launch terminal (mac osx) and type 'ack <some_keywords>'
	#ack will search all files in the current directory & sub-directories

	#here's how I have my config file setup. this file is located on mac osx here
	# ~/.ackrc

	# Always sort the files

	import java.security.MessageDigest;
	import java.util.Arrays;
	import javax.crypto.Cipher;
	import javax.crypto.SecretKey;
	import javax.crypto.spec.SecretKeySpec;

	import org.apache.commons.codec.binary.Base64;

	/**
	* Simple TripleDES Encrypt/Decrypt Test

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

	import sublime
	import sublime_plugin
	import re


	class CompactExpandCssCommand(sublime_plugin.TextCommand):
	def run(self, edit, action='compact'):
	rule_starts = self.view.find_all('\{')
	rule_ends = self.view.find_all('\}')

	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;
	import org.springframework.security.web.session.InvalidSessionStrategy;
	import org.springframework.util.StringUtils;

	import javax.servlet.ServletException;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;
	import java.io.IOException;

	IE6 Only
	==================
	_selector {...}

	IE6 & IE7
	==================
	*html or { _property: }

	IE7 Only
	==================