public FilteredIterable retain()

in core/src/main/java/org/apache/commons/functor/core/collection/FilteredIterable.java [106:117]

• 12 lines of code
• 3 McCabe index (conditional complexity)

    public FilteredIterable<T> retain(Predicate<? super T> filter) {
        if (filter == null) {
            throw new NullPointerException("filtering predicate was null");
        }
        synchronized (this) {
            if (this.predicate == null) {
                this.predicate = new And<T>();
            }
            this.predicate.and(filter);
        }
        return this;
    }