[[Singletonizer]] (called [[ObjectAlgebra]] in newer literature) is a simplification of [[Factory]] by use of [[Generics]]. It is very useful pattern for creating [[ProviderAPI]]. On the other hand, it is not that useful for [[ClientAPI]], as its use requires an [[OpenClass]] concept. [[Singletonizer]] is the simplest way to emulate [[Abstract Data Type]]s in [[OOP]] languages.

[[Singletonizer]] (called [[ObjectAlgebras]] in newer literature) is a simplification of [[Factory]] by use of [[Generics]]. It is very useful pattern for creating [[ProviderAPI]]. On the other hand, it is not that useful for [[ClientAPI]], as its use requires an [[OpenClass]] concept. [[Singletonizer]] is the simplest way to emulate [[Abstract Data Type]]s in [[OOP]] languages.

[[Singletonizer]] is a simplification of [[Factory]] by use of [[Generics]]. It is very useful pattern for creating [[ProviderAPI]]. On the other hand, it is not that useful for [[ClientAPI]], as its use requires an [[OpenClass]] concept. [[Singletonizer]] is the simplest way to emulate [[Abstract Data Type]]s in [[OOP]] languages.

[[Singletonizer]] (called [[ObjectAlgebra]] in newer literature) is a simplification of [[Factory]] by use of [[Generics]]. It is very useful pattern for creating [[ProviderAPI]]. On the other hand, it is not that useful for [[ClientAPI]], as its use requires an [[OpenClass]] concept. [[Singletonizer]] is the simplest way to emulate [[Abstract Data Type]]s in [[OOP]] languages.

[[Singletonizer]] is a simplification of [[Factory]] by use of [[Generics]]. It is very useful pattern for creating [[ProviderAPI]]. On the other hand, it is not that useful for [[ClientAPI]], as its use requires an [[OpenClass]] concept.

[[Singletonizer]] is a simplification of [[Factory]] by use of [[Generics]]. It is very useful pattern for creating [[ProviderAPI]]. On the other hand, it is not that useful for [[ClientAPI]], as its use requires an [[OpenClass]] concept. [[Singletonizer]] is the simplest way to emulate [[Abstract Data Type]]s in [[OOP]] languages.

 

== Real Example ==

== Real Example ==

[[Singletonizer]] is a simplification of [[Factory]] by use of [[Generics]]. It is very useful pattern for creating [[ProviderAPI]]. On the other hand, it is not that useful for [[ClientAPI]], as its use requires an [[OpenClass]] concept.

[[Singletonizer]] is a simplification of [[Factory]] by use of [[Generics]]. It is very useful pattern for creating [[ProviderAPI]]. On the other hand, it is not that useful for [[ClientAPI]], as its use requires an [[OpenClass]] concept.

Instead of having one class representing a [[Factory]] which creates another class representing the ''data'', one can move all the methods into one class:

Instead of having one class representing a [[Factory]] which creates another class representing the ''data'', one can move all the methods into one class:

[[Category:APIDesignPatterns]]

[[Category:APIDesignPatterns]]

[[Category:APIDesignPatterns:Creational]]

[[Category:APIDesignPatterns:Creational]]

[[Category:APIDesignPatterns:Accuracy]]

[[Category:APIDesignPatterns:Clarity]]

<source lang="java" snippet="day.end.bridges.DigestImpl"/>

<source lang="java" snippet="day.end.bridges.DigestImpl"/>

Btw. the ''DigestImpl'''s '''ACCESSOR''' field in example of [[FriendPackages|friend accessor pattern]] to access protected methods of ''Digestor'' class located in different package.

Btw. the ''DigestImpl'''s ''ACCESSOR'' field, which slightly complicates the code, is an example of [[FriendPackages|friend accessor pattern]] allowing us to access '''protected''' methods of ''Digestor'' class located in different package.

<comments/>

<comments/>

<source lang="java" snippet="day.end.bridges.CountingDigestor"/>

<source lang="java" snippet="day.end.bridges.CountingDigestor"/>

[[Singletonizer]] is useful when representing complex graphs or tree hierarchies. One can have a class in a [[ClientAPI]] that represents each graph's [[wikipedia::Graph_Vertex|vertex]]. There can be tons of its instances. Yet plugging in behaviour for each instance can be quite simple. They can all delegate to single [[Singletonizer]] implementation which handles all their operation. Thus they are basically ''singletonizing'' behaviour of many instances to one - hence the name [[Singletonizer]].

[[Singletonizer]] is useful when representing complex graphs or tree hierarchies. One can have a class in a [[ClientAPI]] that represents each graph's [[wikipedia::Graph_Vertex|vertex]]. There can be tons of its instances. Yet plugging in behaviour for each instance can be quite simple. They can all delegate to single [[Singletonizer]] implementation which handles all their operation. Thus they are basically ''singletonizing'' behaviour of many instances to one - hence the name [[Singletonizer]]:

 

 

Btw. the ''DigestImpl'''s '''ACCESSOR''' field in example of [[FriendPackages|friend accessor pattern]] to access protected methods of ''Digestor'' class located in different package.

<comments/>

<comments/>

<source lang="java" snippet="day.end.bridges.CountingDigestor"/>

<source lang="java" snippet="day.end.bridges.CountingDigestor"/>

[[Singletonizer]] is useful when dealing with complex graphs of tree hierarchies. One can have an [[ClientAPI]] with a class that represents a [[wikipedia::Graph_Vertex|vertex]] in a graph. Thus having tons of instances and yet, they all can delegate to just one [[Singletonizer]] implementation that handles all their operation. Thus they are basically ''singletonizing'' number of instances to one - hence the name [[Singletonizer]].

[[Singletonizer]] is useful when representing complex graphs or tree hierarchies. One can have a class in a [[ClientAPI]] that represents each graph's [[wikipedia::Graph_Vertex|vertex]]. There can be tons of its instances. Yet plugging in behaviour for each instance can be quite simple. They can all delegate to single [[Singletonizer]] implementation which handles all their operation. Thus they are basically ''singletonizing'' behaviour of many instances to one - hence the name [[Singletonizer]].

<comments/>

<comments/>

[[Category:APIDesignPatterns]]

[[Category:APIDesignPatterns]]

[[Category:APIDesignPatterns:Evolution]]

[[Category:APIDesignPatterns:Creational]]

[[Category:APIDesignPatterns:Accuracy]]

[[Category:APIDesignPatterns:Accuracy]]

[[Singletonizer]] is useful when dealing with complex graphs of tree hierarchies. One can have an [[ClientAPI]] with a class that represents a [[wikipedia::Graph_Vertex|vertex]] in a graph. Thus having tons of instances and yet, they all can delegate to just one [[Singletonizer]] implementation that handles all their operation. Thus they are basically ''singletonizing'' number of instances to one - hence the name [[Singletonizer]].

[[Singletonizer]] is useful when dealing with complex graphs of tree hierarchies. One can have an [[ClientAPI]] with a class that represents a [[wikipedia::Graph_Vertex|vertex]] in a graph. Thus having tons of instances and yet, they all can delegate to just one [[Singletonizer]] implementation that handles all their operation. Thus they are basically ''singletonizing'' number of instances to one - hence the name [[Singletonizer]].

[[Category:APIDesignPatterns]]

[[Category:APIDesignPatterns]]

[[Category:APIDesignPatterns:Evolution]]

[[Category:APIDesignPatterns:Evolution]]

[[Category:APIDesignPatterns:Accuracy]]

[[Category:APIDesignPatterns:Accuracy]]