All Downloads are FREE. Search and download functionalities are using the official Maven repository.

dev.marksman.collectionviews.SetHelpers Maven / Gradle / Ivy

Go to download

Low overhead, protected views over Java collections

There is a newer version: 1.2.3
Show newest version
package dev.marksman.collectionviews;

/**
 * Helper methods for implementers of custom {@link Set}s.
 * 

 * If you are implementing a custom {@link Set}, your {@code equals} and {@code hashCode}
 * methods SHOULD delegate to {@code setEquals} and {@code setHashCode}, respectively.  This will
 * ensure that equality works correctly with the built-in {@link Set} types.
 * 

 * Your {@code toString} method MAY delegate to {@code setToString}.
 */
@SuppressWarnings("WeakerAccess")
public final class SetHelpers {

    private SetHelpers() {

    }

    @SuppressWarnings("unchecked")
    public static boolean setEquals(Set set, Set other) {
        if (set == null || other == null) {
            return false;
        }
        if (other == set) {
            return true;
        }
        if (other.size() != set.size()) {
            return false;
        }
        return containsAllElements((Set) other, (Iterable) set);
    }

    public static int setHashCode(Set set) {
        int result = 0;
        for (Object obj : set) {
            if (obj != null) {
                result += obj.hashCode();
            }
        }
        return result;
    }

    public static String setToString(Set set) {
        return Util.iterableToString("Set", set);
    }

    private static boolean containsAllElements(Set set, Iterable elements) {
        for (Object elem : elements) {
            if (!set.contains(elem)) {
                return false;
            }
        }
        return true;
    }

}
    

    

    

            

    

            



    
    






    
© 2015 - 2024 Weber Informatics LLC | Privacy Policy