composition over inheritance example

Before we compare composition over inheritance programmatically, let’s have a quick definition of them. There is another problem. Komposition anstelle von Vererbung (engl. The overall design quickly becomes unwieldy and inflexible. Perhaps you want to add a new type of cheese to, Composition allows you to delay the creation of components until they are needed, or to never create them at all if they are not needed. Click here to read it now. Then, the Monster class would call “Attack(opponent)”, look through its available IAttack objects, check which would do the most damage against the opponent, and use that for the attack. The above example — a very simple one — could easily have private fields, public properties, and a constructor to allow it all to be created in one shot. every derived monster needs. then its so easy with xml parser to grab all the correct attacks and drop the correct delegate into your primary and secondary attack methods for the range. Sometimes, a project needs several classes that appear to be similar, but have different behavior. The composition approach provides stronger encapsulation than inheritance, because a change to a back-end class does not necessarily break any code that relies on the front-end class. Inheritance in Python is nice since it facilitates a great deal of code reuse. It’s common to create examples of using inheritance to define vehicles, adding wheels and a steering method. I’m doing something like what you described with the different attack methods in a “real” program at work. Durch dieses Prinzip werden Klassen entkoppelt, was zu flexibleren und stabileren Entwürfen führt. Every developer seems to know about it but few developers seem to actually put it into practice. We create a base class. by Federico Ramirez 06/29/2020 06/29/2020. A lot of people are going to tell you that if something has a “is a” relationship, then you should use inheritance. In the case above, you might think about adding ILight and ITrailerHitch as interfaces to be used by vehicles that can use them. He, like all of us, is very happy to work on amazing projects and make business owners of his town satisfied. You can’t do that with inheritance. It might look like this: You’d be hard-pressed to describe a pizza that this single class can’t encompass. So, you make the Monster class into a base class, and create three new sub-classes from it: BitingMonster, KickingMonster, and PunchingMonster. In the example above, we added a class for any animal that can walk, and a class for any animal that can swim. In the composition approach, the derived class becomes the front-end class and the base class becomes the back-end class. In this case, the composition class should be responsible for doing all necessary memory management itself (not the user of the class). I will Create some strategy delegates for each type of attack, Within each range have your primary and secondary attacks, create interfaces for your ranges. Notify me of follow-up comments by email. Note that Boat and Car aren’t all that different in their declaration, except that a car has wheels and can brake. Your composed class can be easily added to without repercussions. My program parses data, and get get values from different locations, depending on the data source. Welcome to Cash Chahiye Loan Agency (+91) 9414160037 Search for: Home; About; Services. So far we’ve been doing class composition; composing classes from small bits and pieces. Design and Document Classes for Inheritance or Else Prohibit It. If we try to determine the “type” of an object, to determine what attacks it can perform, we can only check against the single base class – not the second class. This … To add the cobra, we only needed to add it to the enum, and add a new “case” (starting at line 45) to create the cobra – by composing a monster that can bite and spit. So, the parser class accepts parsing strategy objects that implement the IDataParser interface. Excellent tutorials/explanations, much appreciated. For example, a Car is a Vehicle. Class hierarchies are very hard to change once they’ve been deployed. Inheritance and composition are two programming techniques developers use to establish relationships between classes and objects. Perhaps it is in a module outside of your control, and the superclass is very heavy with many dependencies. Use Interfaces Only to Define Types 23 Effective Java! In this case, we will have a single Monster class, and “compose” it with the appropriate attack behavior for each type of monster. It’s easy to misinterpret the phrase. Now, you need to have monsters that can also attack by spitting. But there is a better way. Then, when the Monster attacks, its Attack() function could look at its available Attack objects and select the best one for the current opponent. { But your customers will want more ingredients. Let’s look at an example to illustrate the point. Delegation: composition and inheritance in object-oriented programming. Personally, I’d wait until I thought I was close to being finished with the battle logic before moving the values to XML files. Of the three OOP principles, inheritance was probably the second principle that you came to understand after encapsulation. In the phrase “composition over inheritance,” composition refers to object composition. private readonly ICanBite bite; Both composition and inheritance are object-oriented programming concepts.They are not tied up with any specific programming language such as Java. So ist es möglich, zur Laufzeit das Verhalten einer Klasse zu verändern. It also provides a vastly simpler, more testable codebase. He is having the time of is life. For example, the BitingKickingMonster inherits from BitingMonster, and duplicates the KickDamage property – because it could not also inherit from KickingMonster. Required fields are marked *. You should really feel special. Because this is getting complex, you also build a Factory class, to create the different types of monster objects. 3. share | improve this answer | follow | edited Feb 12 '18 at 9:24. answered Feb 12 '18 at 6:30. Balance Transfer; Business Loan; Mortgage Loan When there is a composition between two entities, the composed object cannot exist without the other entity. Hey! Let’s pretend you work at a game programming company. Note that it is said to prefer composition over inheritance. }. You might be stuck with pizzas that no one ever orders. It should be easy to extend. I loved the way you walked through the post. But, what do you do if you have a new monster that needs to bite and kick? Using inheritance, you are going to get a rather deep and wide inheritance model really quickly. Inheritance is cool and everything, but it has its problems. Nice post! If an order is deleted then all corresponding line items for that order should be deleted. The Monster class would have a List that is populated when the Monster object is instantiated. Your email address will not be published. Another way to look at the composition over inheritance issue is via interfaces. Creating it causes side-effects that you don’t want or aren’t prepared for. this.bite = bite; In Decorator pattern, we don't extend any class to add additional functionality, instead we keep an instance of the class we are decorating and delegates original task to that class after doing decoration. Inheritance is a powerful feature, but it can get out of control. I’m 100% of the time the guy who finds useful content and just leeches it up without telling the author how much I appreciate it. A LowBite (by a rat) would check against the player’s boots stats. also this means that if you have a list of monsters that are roaming the passages,you can easly extract those with certain attacktypes also in your base class you can have a virtual primary and secondary attack method which is overwritten in your inherited classes. The various interfaces available are enough to define the functionality of almost any vehicle, and if they aren’t, it’s pretty simple just to add another one. NOTE: The implementation of composition in this example is extremely simple. Composition implements a has-a relationship, in contrast to the is-a relationship of subtyping. The different types of monsters could be able to do different attacks – biting, kicking, or punching. } This is going to get complicated really fast, isn’t it? Prefer Class Hierarchies to Tagged Classes 24 Effective Java! Composition is a more modular approach in which a class contains instances of other classes that bring their own abilities with them. For example, A base class Shape has a derived classes like Circle, Square, Rectangle, etc. In this Twitch live stream, Brendan extracts our payment processing logic using composition instead of inheritance, showing the difference. This is a little more complex than the previous factory, because this is where we “compose” the Monster object, to act like a BitingMonster object (or, whatever attacks the monster can perform). So far, I like that design for the program. { If you are into object-oriented programming, you most likely have heard about composition over inheritance. (It always comes back to interfaces, doesn’t it?). Just wondering if this would be a viable way to go. We’d fill that with all classes that implement IAttack and are the appropriate attack type for this monster. Inheritance implements the IS-A relationship. You can’t change a superclass without risking breaking a user’s subclass. It always comes back to interfaces, doesn’t it? If we need to look for data in another place, we just need to write a new parser class that implements IDataParser and add it to the parsing object’s list of available parsing strategies. Cobras will bite and spit, camels will kick and spit, etc. For example, instead of inheriting from class Person, class Employee could give each Employee object an internal Person object, which it then has the opportunity to hide from external code even if class Person has many public attributes or methods. For example, if order HAS-A line-items, then an order is a whole and line items are parts. Awesome tutorial, that’s exactly how OOP concepts should be taught. If you do that, they can be used to compose classes using those interfaces rather than inheritance, resulting again in more flexibility. For example, instead of being an Animal, the child classes now have anAnimal. Design Interfaces for Posterity 22 Effective Java! private readonly ICanBite bite; public BittingMonsterICanBite bite) Thanks for sharing the link. Using inheritance, you might create a BitingKickingMonster. private readonly ICanKick kick; public KickingMonsterICanKick damage) But these tutorials are really helpful, thank you for writing them. I build one “Parser” class, load it with the strategy objects it needs for the particular file, and it parses it. It doesn’t say always use composition over inheritance. Interestingly, inheritance has somewhat fallen out of favor recently, giving way instead to the notion of composition. This technique is even more powerful when you combine it with with the Strategy design pattern or Command design pattern. We create a base class. 6 Comments → Composition over Inheritance. class BittingMonster() : Monster Creating a new, special pizza on the fly can be impossible. It goes into many of the things you might need to think about if you try to use inheritance, or use composition over inheritance. If you start with putting the parameters in XML, you’ll need to keep the XML in sync – which will probably be more difficult than using something like a factory class to instantiate and set the properties for your strategy objects (where you’ll have more help from IntelliSense). Your email address will not be published. Perhaps your, You can also design your classes so that components can be dynamically changed if need be. With these six properties, we can compose the Monster object to attack however we want – which we do in the MonsterFactory class below. Composition But, that can sometimes lead to messy code. We’ll end up with: And, of course, some customers may want both, so you’ll need: Now, let's add in sausages onions, anchovies, and black olives. then you can call method primary attack on every monster and every monster will attack correctly to its type. This post will be looking at inheritance and some of the pitfalls of trying to create your domain model primarily through inheritance. So, if it can’t find the data with the first parsing strategy object, it will try the next one. The next day, your boss tells you they need new types of monsters in the game – ones that can do different combinations of biting, kicking, and punching. The Monster class could have a List variable to hold its Attack objects. It’s great to hear these are helping people. I think this also explains why many posts about composition over inheritance propose mixins as the solution. “Favor composition over inheritance” is a phrase that I hear spoken a lot but which describes a concept I rarely actually see in real world code. ... That way, it will typically become much clearer why and when composition over inheritance is the right approach. A better way to do this might be to combine it with the Command Design Pattern, and pass in different Attack command objects for the different types of attacks. Composition allows you to do in that one class what might take 2^n classes via inheritance. You have a base class monster. }. { You’ll have a lot of code to write when the boss decides to add pineapple to the pizza (setting aside the fact that pineapple on pizza is an utter abomination). The concept itself is simple: Whenever possible, prefer to compose objects rather than introducing inheritance … What is “prefer composition over inheritance”? this.kick= kick; For instance, cars and motorbike are vehicles which means they can inherit from the Vehicle class, it is also true that cars and motorbike have engines and wheels so than be composite using those elements. There is also a new monster: the cobra, which can bite and spit. Eric Lippert wrote about a similar topic to some extent. [C# Design Patterns] The Prototype Pattern, Using ReSharper for clean and consistent C# code, [C# Design Patterns] Composition Over Inheritance. but in my opinion inheritance is the right design pattern here…. After you finish creating all these classes, your boss sends you an email. it would be a cinch in xml to change any attribute you wished. However, adding the implementation of the SpitAttack on the Monster.cs class seems to me like a violation of the Open/Closed principle. So i think this i much more flexible and readable. This post will demonstrate the difference between using inheritance and using composition. With this Monster class, when we create a new Monster object, we “compose” its Attack options by calling the AddAttackType() function – with the AttackType, and the amount of damage the monster does with this attack. For example, take the classic example of Vehicle. What is “prefer composition over inheritance”? Since functions are first class objects in Python, why not simplify even further and pass in send functions rather than adapter classes in the composition example. For example, Mattias “is a” man, thus I can inherit man. Composition vs Inheritance. Let’s look at a couple of examples. If you need to expand the definition of what a pizza is, you can do so easily without affecting existing uses of the Pizza class. But just a thought…. Hmm. Object-oriented programming (OOP) is a methodology that was introduced in the 60s, though as for many other concepts related to programming languages it is difficult to give a proper date. Sometimes, a project needs several classes that appear to be similar, but have different behavior. composition over inheritance oder composite reuse principle) ist eine Technik im Softwareentwurf. Composition Over Inheritance. this.kick = kick One never can be quite sure what the super-class is going to do. You want to write a system to manage all your pizzas. Great post scott. The Cat and Dog classes c… If you guys would like to check it out, you can find it here: I know its probably out of scope of this tutorial, but i was wondering if there was a way of demonstrating the composition over inheritance without violating OCP, or any other SOLID principle. Then, we create sub-classes that inherit from the base class, and have the properties and functions that are unique to the sub-class. In the example above, we forgot to give the animal class a Walk() function. With inheritance, we need to change the Animalclass again, but we would still have the problem of the fish. With this approach you don´t get so complexe inheritance, where one class interhit from more than one. In object-oriented programming, we will often handle this with inheritance. Your properties aren’t going to cover all the possible situations that happen as more ingredients are added. With the composition method, when our boss tells us to add a new “Spit” attack, instead of creating new classes, we would only need to: Then, MonsterFactory.cs can create monsters that can use the new “spit” attack. Wikipedia’s definition and example of Composition over Inheritance focuses only on domain modelling, and I’m generally not a fan of conclusions such as: To favor composition over inheritance is a design principle that gives the design higher flexibility, giving business-domain classes and more stable business domain in the long term. Well, composition of interfaces can allow for this kind of thing. We’ll assume that all self-respecting pizzas have tomato sauce, so we’ll create: That’s great. By Leonardo Giordani 17/08/2020 OOP Python Python3 Share on: Twitter LinkedIn HackerNews Email Reddit Introduction¶. You can definitely do a better form of Composition Over Inheritance by using interfaces and other design patterns, like the strategy pattern. Eric’s series of posts is great – which is not a surprise (he writes a lot of great stuff). Notice that we run into a problem when a new class needs to inherit from more than one base class. You might also combine object composition with the Strategy Design Pattern. } There are strategy classes to find the different values in the different formats. this.bite = bite; Inheritance and polymorphism expand a class's behavior through a class hierarchy, with properties and methods passed down through the generations. Classes designed using composition are straightforward, flexible, and robust (in that they clean up after themselves nicely). With composition, it’s as simple as adding two new classes. There are two common situations when you would want to consider using composition, instead of inheritance: when you need to do multiple inheritance, and when your sub-classes start to have their own sub-classes. If you were writing a game, you might have different types of monsters. }. It’s not the same topic, but for some extent it’s relevant (but maybe just because it’s based on RPG topic too :D). As I mentioned, it encourages a gaggle of unwieldy subclasses. I was having a hard time grasping composition and finding a practical example, this one is fantastic to visualize better what composition is and the benefit. That could inherit from Monster, BitingMonster, or KickingMonster. 20 Effective Java Tuesday! Favor Composition Over Inheritance 19 Effective Java Tuesday! Instead of composing the object with property values (the attack type and damage), you could also compose it by configuring how it will perform its actions. Inheritance is contrasted with object composition, where one object contains another object (or objects of one class contain objects of another class); see composition over inheritance. How to Misuse Inheritance - Example 1 Let’s start with a simple and extremely common example of misusing inheritance: class Stack extends ArrayList { public void push(Object value) { … } public Object pop() { … https://ericlippert.com/?s=Wizards+and+warriors&submit=Search, Add a new “Spitting” value to the AttackType enum in Monster.cs, Add a new “CanSpit” property to Monster.cs, Add a new “SpitDamage” property to Monster.cs. Posted in JavaScript, Ruby, Ruby on Rails, Software Design, Web Development. A less debatable example, where composition will be the better tool in a more obvious manner, would probably make things clearer. The code might look like this: Then, your boss tells you the game needs to have different types of monsters. Easy as pie, right? { Another good example of using composition over inheritance is Decorator design pattern. Python’s logging module is a good example in the Standard Library itself of a module that follows the Composition Over Inheritance principle, so let’s use logging as our example. Instead of creating more sub-classes, you decide to try using composition. Since one of the most common causes of inter-object dependencies wreaking havoc on maintainability is the lack of understanding of Class Responsibilities, and in particular the overuse (or use at all) of Inheritance, I will focus on the well-known example of Composition Over Inheritance. You’re building a new game, and you create a Monster class, with two properties – HitPoints and AttackDamage. (hope it’s not a problem that I linked ). The doctrine of composition over inheritance advocates implementing has-a relationships using composition instead of inheritance. In a real project, you might want to use the Strategy Pattern, the Command pattern, or another technique, to implement the different behavior. To give the Camel a new attack ability, we only needed to add one line (line 53). Each strategy class only does one thing, which makes it very small and simple – which helps prevent creating bugs. Notice that the Camel can now kick and spit. Once you’ve created. I like the Composition method, but using different attacktypes as an interface, Then you can have an attack method which only accepts the correct attacktype interface. Inheritance and compositionare two major concepts in object oriented programming that model the relationship between two classes. Inheritance has its place — it’s just not usually the best choice when designing a class framework. Both could be added and composed with relative ease and a lack of pain to existing users of the class framework. Let’s start with pepperoni and mushrooms. Therefore when using inheritance, you are making use of an “is a” relationship. Finding an Audience for Your Side Business. It is more flexible, allowing for multiple cheese types, sauce types, and a practically infinite collection of ingredients. An overemphasis on reuse can lead to tragically flawed designs. They drive the design of an application and determine how the application should evolve as new features are added or requirements change. We put common data and behavior into a Base class and then implement any extra data and behavior needed in derived classes. Hi, thank you for this post you made this complex concept so easy to understand. Thanks! Doc Brown Doc Brown. Here we have a collection of interfaces that can be put together — composed, if you will — to create any kind of vehicle, even a boat. that implement the interface. Pretend you own a pizza shop. So first of all this should be implemented as an abstract class, which only contains functionality or properties which This existing class is called the baseclass, and the new class is referred to as the derived class. Thank you. class KickingMonster() : Monster More examples. How about we “compose” a pizza instead: That is a perfect example of why you should prefer composition over inheritance. Then, we could account for the player’s armor. https://ericlippert.com/?s=Wizards+and+warriors&submit=Search Implementation Why favor Composition over Inheritance [example in PHP]? Then, we create sub-classes that inherit from the base class, and have the properties and functions that are unique to the sub-class. For me Biting, Kicking or Punching functionality should be completly extracted an injected via Interface…. This is the best post I’ve read on Composition over inheritance. Then along comes a boat, and you aren’t sure what to do. Have you looked at the Strategy Pattern? Inheritance has its place — it’s just not usually the best choice when designing a class framework. The IAttack interface might define “void Attack(LivingCreature opponent)”, with that function being the one the monster will use in battle. It’s a pretty basic idea — you can augment an existing class while still using all the capabilities of the parent class. This is a very nice example, and it was very helpful. Composition is used extensively in Flutter's UI framework. It doesn’t say always use composition over inheritance. It takes a list of IDataParser objects. So, you start out with a base class: Now, of course, that’s a nice abstract class, so we have to descend from it. I noticed it trevor is a animal, the child classes now have anAnimal good example of using to. Im Softwareentwurf it was very helpful and Car aren ’ t want or ’! Or punching parsing strategy object, it will typically become much clearer why and when composition over inheritance is and! Biting punching monster is Mike Tyson design your classes so that components composition over inheritance example be beneficial to futureproof code... And some of the fish is very small and easy to understand of! A cinch in xml to change any attribute you wished you also build a Factory class, and (! Logging class that does the job of the parent class rather than inheritance, again... We compare composition over inheritance adding two new classes need be definitely see how can. Patterns, like all of us, is very heavy with many, many that... What the super-class is going to get a rather deep and wide inheritance model quickly... ( it always comes back to interfaces, doesn ’ t encompass loved the way you walked through the.. They do it in different ways is Decorator design pattern an application determine... Composition of interfaces can allow for this monster use of an application and determine how the should! Explains why many posts about composition over inheritance propose mixins as the solution?.... that way, it will typically become much clearer why and when over. Isn ’ t change a superclass without risking breaking a user ’ s look an. Application and determine how the application should evolve as new features are added or requirements.! Me biting, kicking or punching functionality should be implemented as an abstract class, with properties functions... With properties and functions that are unique to the sub-class a viable to! Get out of favor recently, giving way instead to the sub-class has wheels and can.! 17/08/2020 OOP Python Python3 share on: Twitter LinkedIn HackerNews Email Reddit.. Compose classes using those interfaces rather than inheritance, where one class also has all possible! Answered Feb 12 '18 at 9:24. answered Feb 12 '18 at 6:30 adding the implementation of entire. Has its problems a new, special pizza on the fly can be impossible Software design, Web.... That it is more flexible, allowing for multiple cheese types, sauce,. Application should evolve as new features are added or requirements change your pizzas, to create the values! The super-class is going to get a rather deep and wide inheritance really., KickAttack, PunchAttack, etc. ) of creating more sub-classes, you also build a Factory class and... Opinion inheritance is a more modular approach in which a class using composition instead creating... This also explains why many posts about composition over inheritance advocates implementing has-a using... Of your control, and PunchDamage ) attribute you wished composition over is. The third by punching hit ” against the player ’ s as simple adding! Are unique to the sub-class augment an existing class while still using all the possible that! An example to illustrate the point love him any attribute you wished now anAnimal! Monster class would have a List that is a South African freelance web-developer, he has been for. Called the baseclass, and you aren ’ t going to cover all the Damage properties in it BiteDamage. That implement IAttack and are the appropriate attack type for this monster down the. Class interhit from more than one programmatically, let ’ s look at a game programming.! End up with any specific programming language such as Java with the different types monsters... Without the other entity High, Medium, and so on by biting, BitingKickingMonster... Instead: that ’ s helmet stats interfaces can allow for this post you made this concept..., giving way instead to the notion of composition ’ t encompass the and! Also inherit from the base class, which only contains functionality or properties which every derived monster needs on projects... Projects and make business owners of his town satisfied use of an “ a... To write a system to manage all your pizzas look like this: then, we create sub-classes that from. Relationship between two classes when there is a South African freelance web-developer, he has been doing composition... Cobras will bite and spit, etc. ), they can be quite what. Capabilities of the parent class high-quality articles on other sites i think Python the. Do that, they can be easily added to without repercussions practically infinite collection of ingredients if be... Kickattack, PunchAttack, etc. ) we create sub-classes that inherit from the class! On amazing projects and make business owners of his town satisfied needed to send messages. Data with the strategy pattern need be inheritance or Else Prohibit it when using inheritance and compositionare two concepts... Of trying to create the different types of monster objects hierarchy, with properties. Could not also inherit from more than one unique to the notion of composition in example! That different in their declaration, except that a Car has wheels and steering... That design for the player ’ s one class that does the of. Is instantiated, is very heavy with many dependencies your needs of us, is happy! The solution, Square, Rectangle, etc. ) testable codebase the Camel can now kick spit! To create your domain model primarily through inheritance another good example of why you should prefer composition over inheritance is! Place — it ’ s just not usually the best way und stabileren Entwürfen führt Shape has a classes. Strategy class only does one thing, which can bite and spit to go encompass. Creating bugs that way, it ’ s have a List variable to hold its objects... All self-respecting pizzas have tomato sauce, so we ’ d be hard-pressed to describe pizza! 53 ) gained subclasses as developers needed to send log messages to new destinations and (. That way, the code somewhat Mattias “ is a very nice example, Mattias is... Quick definition of “ composition over inheritance is its “ hit ” against the player ’ s exactly how concepts., thank you for this monster the first parsing strategy objects that implement IAttack and are the attack. Class only does one thing, which only contains functionality or properties which every derived monster.! Composition ” is, “ combining parts or elements to form a while ” what might take classes! Parts or elements to form a while and his clients love him the fish thus i can inherit man relationship! Right approach, so we ’ ve been deployed i am new ( ish ) computer. You want to write a system to manage all your pizzas model really quickly ist eine Technik Softwareentwurf... You the game needs to have different behavior with any specific programming language for beginners use when. Basic idea — you can design a class framework, Software design, Development. Composed class can ’ t find the data source ” program at work boss tells you game... Awesome you are, Software design, Web Development that has gradually gained subclasses as needed! You ’ d fill that with all classes that bring their own abilities with them the above... Classes so that components can be quite sure what the super-class is to! You to do is also a new monster that needs to bite and spit, will! If need be be deleted described with the strategy design pattern ( ). The entire inheritance structure that we run into a base logging class that does the of... S one class what might take 2^n classes via inheritance BitingMonster, and Low versions of attacks. The animal class a Walk ( ) function a base logging class that has gradually gained subclasses developers. Of these attacks for creatures of different heights build a Factory class, and you ’. It has its place — it ’ s just not usually the best when! Has-A relationship, in contrast to the sub-class there are strategy classes to find the different formats of using.. A similar topic to some extent add one line ( line 53.... Me biting, kicking or punching classes like Circle, Square, Rectangle, etc )! With two properties – HitPoints and AttackDamage, so we ’ ll create: that a. Linkedin HackerNews Email Reddit Introduction¶, the code is very heavy with many dependencies put common data and behavior in... Variable to hold its attack objects class interhit from more than one base class and implement...

Cover Letter Physician Assistant New Grad Example, Sharpe Spray Gun Review, Tennis Backpack Adidas, What Is After Gen Z, What Is Tableau Used For,

happy wheel

Comments are closed.

ThemeLark