Predicates.java

package edu.berkeley.nlp.util.functional;

/**
 * Created by IntelliJ IDEA.
 * User: aria42
 * Date: Oct 9, 2008
 * Time: 6:32:13 PM
 */
public class Predicates {
	public static<I> Predicate<I> getTruePredicate() {
		return new Predicate<I>() {
			public Boolean apply(I input) {
				return true;
			}
		};
	}
	public static<I> Predicate<I> getInversePredicate(final Predicate<I> pred) {
		return new Predicate<I>() {
			public Boolean apply(I input) {
				return !pred.apply(input);
			}
		};
	}
	public static<I> Predicate<I> getOrPredicate(final Predicate<I>...preds) {
		return new Predicate<I>() {
			public Boolean apply(I input) {
				for (Predicate<I> pred: preds) {
					if (pred.apply(input)) return true;
				}
				return false;
			}
		};
	}

  public static Predicate getNonNullPredicate() {
    return new Predicate() {
      public Boolean apply(Object input) {
        return input != null;
      }
    };
  }

	public static<I> Predicate<I> getAndPredicate(final Predicate<I>...preds) {
		return new Predicate<I>() {
			public Boolean apply(I input) {
				for (Predicate<I> pred: preds) {
					if (!pred.apply(input)) return false;
				}
				return true;
			}
		};
	}
}