package org.psjava.util;

import java.util.Iterator;

import java.util.function.Predicate;

public class FilteredIterator {

public static <T> Iterator<T> create(final Iterator<? extends T> a, final Predicate<T> filter) {

return new ReadOnlyIterator<T>() {

T next = null;

Iterator<? extends T> cursor = a;

@Override

public boolean hasNext() {

tryToStepNext();

return next != null;

}

@Override

public T next() {

tryToStepNext();

T r = next;

next = null;

return r;

}

private void tryToStepNext() {

while (next == null && cursor.hasNext()) {

T value = cursor.next();

if (filter.test(value))

next = value;

}

}

};

}

}