JavaでLINQ01

とりあえず無限級数。

public class Main {

    public static void main(String[] args) throws InterruptedException {

        for (Integer i : iterate(0, new Func1<Integer, Integer>(){
                                        public Integer _(Integer arg0) {
                                            return arg0 + 1;
                                        }})) {
            
            System.out.println("Hello, World!!" + i);
            Thread.sleep(1000);
        }
        
    }
    
    private static <T> IEnumerable<T> iterate(T initialValue, Func1<T, T> func) {
        
        final class Result implements IEnumerable<T> {
            
            private T initialValue;
            private Func1<T, T> func;

            public Result(T initialValue, Func1<T, T> func) {
                this.initialValue = initialValue;
                this.func = func;
            }
            
            @Override
            public Iterator<T> iterator() {
                
                final class _Result implements Iterator<T> {
                    
                    private T next;
                    private Func1<T, T> func;
                    
                    public _Result(T initialValue, Func1<T, T> func) {
                        this.next = initialValue;
                        this.func = func;
                    }

                    @Override
                    public boolean hasNext() {
                        return true;
                    }

                    @Override
                    public T next() {
                        T next = this.next;
                        this.next = this.func._(next);
                        return next;
                    }

                    @Override
                    public void remove() {
                        throw new NotImplementedException();
                    }
                    
                }
                
                return new _Result(this.initialValue, this.func);
            }
        }
        
        return new Result(initialValue, func);
    }

}

interface Func1<T, TResult> {
    TResult _(T arg0);
}

interface IEnumerable<T> extends Iterable<T> {
}