Comments on: Functors in Java and beyond http://chaoticjava.com/posts/functors-in-java-and-beyond/ The internet, design patterns, frameworks and Java Sat, 05 Nov 2011 18:39:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Paul http://chaoticjava.com/posts/functors-in-java-and-beyond/comment-page-1/#comment-29290 Paul Fri, 04 Apr 2008 14:06:08 +0000 http://chaoticjava.com/posts/functors-in-java-and-beyond/#comment-29290 Great post. For some useful functors check out the commons collections project. It has a functors package with includes Predicates, Closures, and Transformers. http://commons.apache.org/collections/api-release/org/apache/commons/collections/functors/package-summary.html Great post. For some useful functors check out the commons collections project. It has a functors package with includes Predicates, Closures, and Transformers. http://commons.apache.org/collections/api-release/org/apache/commons/collections/functors/package-summary.html

]]> By: Avah http://chaoticjava.com/posts/functors-in-java-and-beyond/comment-page-1/#comment-25955 Avah Thu, 28 Feb 2008 11:34:58 +0000 http://chaoticjava.com/posts/functors-in-java-and-beyond/#comment-25955 Kit: Thanks for all the information! I will take all of this into account when writing more about functors, as I have more to say about them. Kit: Thanks for all the information! I will take all of this into account when writing more about functors, as I have more to say about them.

]]> By: Web 2.0 Announcer http://chaoticjava.com/posts/functors-in-java-and-beyond/comment-page-1/#comment-25876 Web 2.0 Announcer Wed, 27 Feb 2008 10:30:59 +0000 http://chaoticjava.com/posts/functors-in-java-and-beyond/#comment-25876 <strong>Functors in Java and beyond</strong> [...]Functors are defined as a function encapsulated in an object. In most cases, the function’s parameters can be set and the result retrieved using the common accessor pattern, such as setParameter1(Object value) or getResult(). The fact that these... Functors in Java and beyond

[...]Functors are defined as a function encapsulated in an object. In most cases, the function’s parameters can be set and the result retrieved using the common accessor pattern, such as setParameter1(Object value) or getResult(). The fact that these…

]]> By: Kit Davies http://chaoticjava.com/posts/functors-in-java-and-beyond/comment-page-1/#comment-25875 Kit Davies Wed, 27 Feb 2008 09:57:49 +0000 http://chaoticjava.com/posts/functors-in-java-and-beyond/#comment-25875 Good post. "Functions as objects" (or more precisely "functions as first-class types") is exactly the basis for functional programming, eg. Haskell, Lisp, Erlang et al. So yes function composition using functors is going to look similar to the same in Haskell or any FP language. Also possible would be supplying a single parameter to a binary functor to produce a new reusable unary functor with the parameter already "baked in". This gives you currying. Also look at map/reduce. This applies "map" functors to a list to produce new lists, and "reduce" functors to the new lists to produce some kind of cumulative result for each new list. The key benefit being that given appropriate partioning of the initial list, the mapping and reducing functors can operate in parallel, hence the much vaunted scalability of the map/reduce model. Interestingly Scala is a language that aims to provide a combination of FP and OO on the JVM. If this is an area of interest, I suggest you look there also. Finally (phew) FunctionalJ is another library for doing FP in pure Java. Regards Kit Good post.
“Functions as objects” (or more precisely “functions as first-class types”) is exactly the basis for functional programming, eg. Haskell, Lisp, Erlang et al. So yes function composition using functors is going to look similar to the same in Haskell or any FP language.
Also possible would be supplying a single parameter to a binary functor to produce a new reusable unary functor with the parameter already “baked in”. This gives you currying.
Also look at map/reduce. This applies “map” functors to a list to produce new lists, and “reduce” functors to the new lists to produce some kind of cumulative result for each new list. The key benefit being that given appropriate partioning of the initial list, the mapping and reducing functors can operate in parallel, hence the much vaunted scalability of the map/reduce model.
Interestingly Scala is a language that aims to provide a combination of FP and OO on the JVM. If this is an area of interest, I suggest you look there also.
Finally (phew) FunctionalJ is another library for doing FP in pure Java.

Regards
Kit

]]> By: Avah http://chaoticjava.com/posts/functors-in-java-and-beyond/comment-page-1/#comment-25865 Avah Wed, 27 Feb 2008 06:53:25 +0000 http://chaoticjava.com/posts/functors-in-java-and-beyond/#comment-25865 ryan: Interesting. I didn't go into Haskell at all, but I know that many languages has a "functions as objects" feature; interesting to find that some languages actually have a function composition feature built into it. I'll read more about it and see how it relates to functors and their compositions. Thanks! ryan: Interesting. I didn’t go into Haskell at all, but I know that many languages has a “functions as objects” feature; interesting to find that some languages actually have a function composition feature built into it.

I’ll read more about it and see how it relates to functors and their compositions.

Thanks!

]]> By: ryan http://chaoticjava.com/posts/functors-in-java-and-beyond/comment-page-1/#comment-25823 ryan Tue, 26 Feb 2008 18:50:02 +0000 http://chaoticjava.com/posts/functors-in-java-and-beyond/#comment-25823 Is it just me, or is this similar to function composition in Haskell? Is it just me, or is this similar to function composition in Haskell?

]]>