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Design Patterns and Refactoring

Design Patterns and Refactoring

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Implementing Regular Expressions Russ Coxrsc@swtch.com This page collects resources about implementing regular expression search efficiently. Articles and Notes Design Patterns In software engineering, a design pattern is a general repeatable solution to a commonly occurring problem in software design. A design pattern isn't a finished design that can be transformed directly into code. It is a description or template for how to solve a problem that can be used in many different situations. Uses of Design Patterns Inversion of Control Containers and the Dependency Injection pattern In the Java community there's been a rush of lightweight containers that help to assemble components from different projects into a cohesive application. Underlying these containers is a common pattern to how they perform the wiring, a concept they refer under the very generic name of "Inversion of Control". In this article I dig into how this pattern works, under the more specific name of "Dependency Injection", and contrast it with the Service Locator alternative. The choice between them is less important than the principle of separating configuration from use. One of the entertaining things about the enterprise Java world is the huge amount of activity in building alternatives to the mainstream J2EE technologies, much of it happening in open source.

CoreJava Object class of Java is having predefined toString() method. This method by default Object class calls implicitly when an object created. Overriding toString manually is nothing but implementing this method in our class.The java toString() method is used when we need a string representation of an object. It is defined in Object class. Lockpicking LG #150 By Aurelian Melinte "When two trains approach each other at a crossing, both shall come to a full stop and neither shall start up again until the other has gone." -- old Kansas statute Overview

OpenClassroom Full courses. Short Videos. Free for everyone. Learn the fundamentals of human-computer interaction and design thinking, with an emphasis on mobile web applications. A practical introduction to Unix and command line utilities with a focus on Linux. Design pattern (computer science) There are many types of design patterns, for instance Algorithm strategy patterns addressing concerns related to high-level strategies describing how to exploit application characteristics on a computing platform.Computational design patterns addressing concerns related to key computation identification.Execution patterns that address concerns related to supporting application execution, including strategies in executing streams of tasks and building blocks to support task synchronization.Implementation strategy patterns addressing concerns related to implementing source code to support program organization, andthe common data structures specific to parallel programming.Structural design patterns addressing concerns related to high-level structures of applications being developed. History[edit]

SQLite in Android SQLite is at the heart of Android's database support. This database was developed with embedded environments in mind - and is used not only by Android but also by Apple's iOS and Blackberry's system as well as lots of other systems with low memory footprint and comparatively little CPU horsepower. Why SQLite in the first place? Of course there is a reason why SQLite is so dominant in the embedded and also the mobile world. The main reasons are Singleton Pattern Motivation Sometimes it's important to have only one instance for a class. For example, in a system there should be only one window manager (or only a file system or only a print spooler). Usually singletons are used for centralized management of internal or external resources and they provide a global point of access to themselves. The singleton pattern is one of the simplest design patterns: it involves only one class which is responsible to instantiate itself, to make sure it creates not more than one instance; in the same time it provides a global point of access to that instance.

Practice and Learn - Google Code Jam On this page you can see results and code from past rounds of Google Code Jam, and you can try the problems for yourself. If you're new to Code Jam, try following the Quick-Start Guide. Where should I start? If you're new to programming contests, we highly recommend starting with the least difficult problems and moving up from there as you get more confident. Beware: the round that has the easiest problem A may have a very difficult problem B! As you get used to the platform, you can check how many people solved each problem in the "Submissions" box to the left of the dashboard, and use that as a rough gauge of difficulty.

AntiPatterns: The Survival Guide Whereas patterns are good ideas that can be re-applied to new situations, AntiPatterns: The Survival Guide looks at what goes wrong in software development, time and time again. Most software projects fail According to new research, success in 68% of technology projects is "improbable." Poor requirements analysis causes many of these failures, meaning projects are doomed right from the start (ZDnet) Our deadliest hit list begins with the Blob, where one object does most of the work in a project, and proceeds to Continuous Obsolescence, where technology changes so quickly that developers can't keep up. Some of the more entertaining antipatterns include the Poltergeist (where do-nothing classes add unnecessary overhead), the Boat Anchor (a white elephant piece of hardware or software bought at great cost) and the Golden Hammer (a single technology that is used for every conceivable programming problem).

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