What is the best way to filter a Java Collection?

Question

I want to filter a java.util.Collection based on a predicate.

Answer 1

I wrote an extended Iterable class that support applying functional algorithms without copying the collection content.

Usage:

List myList = new ArrayList(){ 1, 2, 3, 4, 5 }

Iterable filtered = Iterable.wrap(myList).select(new Predicate1()
{
    public Boolean call(Integer n) throws FunctionalException
    {
        return n % 2 == 0;
    }
})

for( int n : filtered )
{
    System.out.println(n);
}

The code above will actually execute

for( int n : myList )
{
    if( n % 2 == 0 ) 
    {
        System.out.println(n);
    }
}