问题
I recently moved from C# to Java [again]. But I badly miss lambda expressions and things like IEnumerable.Foreach of C#. So I am looking for a lambda expression library in Java.
are there better libraries than LambdaJ?
Also is clojure directly inlinable in Java programs? That is can I mix clojure code in Java functions?
回答1:
Java 8 might have lambda support natively. Until then you can use a combination of anonymous inner classes and libraries like google-guava. Below are other libraries that you can look into
- http://commons.apache.org/collections/
- http://functionaljava.org/
- http://functionalj.sourceforge.net/
- http://www.agical.com/jambda/
Or better look at Scala
回答2:
The equivalent foreach loop in Java is structured like this
List<Foo> fooList = // some list containing foos
for (Foo foo : fooList){
// do stuff
}
There are no lambda expressions in Java, however if you can wait until Java8 they are adding closures. The closest you can get are anonymous inner classes.
回答3:
The Google Guava library contains Function and Predicate classes that can be used to emulate lambda-like functionality. As kgrad mentions above, you can create anonymous instances of each one.
http://guava-libraries.googlecode.com/svn/trunk/javadoc/com/google/common/base/Function.html
http://guava-libraries.googlecode.com/svn/trunk/javadoc/com/google/common/base/Predicate.html
Although you could easily write classes like these yourself, Guava contains a lot of helper methods that utilize functions and predicates for doing things like transforming or filtering all different types of iterables: http://guava-libraries.googlecode.com/svn/trunk/javadoc/com/google/common/collect/Iterables.html
Note: I realize that Pangea already posted a link to Google Guava above, but I had already started writing this post and thought it would still be useful to provide the links.
来源：https://stackoverflow.com/questions/4775627/lambda-expressions-of-net-in-java