Package 

Class EqualsContract

  • 
public class EqualsContract
    Tests Reflexive, Symmetric, Transitive, Consistent, and non-nullity properties of the equals()contract. If you think this is confusing, realize that there is no way to implement aone-sided equals() correctly with inheritance - it's a broken concept, but it's still used sooften that you have to do your best with it.I got the idea of contract-based testing from watching Bill Venners:https://www.youtube.com/watch?v=bCTZQi2dpl8

    • Method Summary

      Modifier and Type Method Description
      static <T> void permutations(List<T> items, BiFunction<Out Object, Out Object, Out Object> f) Apply the given function against all unique pairings of items in the list.
      static <S, T1 extends S, T2 extends S, T3 extends S, T4 extends S> void equalsHashCode(T1 equiv1, T2 equiv2, T3 equiv3, T4 different, boolean requireDistinctHashes) Tests Reflexive, Symmetric, Transitive, Consistent, and non-nullity properties of the equals()contract.
      static <S, T1 extends S, T2 extends S, T3 extends S, T4 extends S> void equalsSameHashCode(T1 equiv1, T2 equiv2, T3 equiv3, T4 different) Tests Reflexive, Symmetric, Transitive, Consistent, and non-nullity properties of the equals()contract.
      static <S, T1 extends S, T2 extends S, T3 extends S, T4 extends S> void equalsDistinctHashCode(T1 equiv1, T2 equiv2, T3 equiv3, T4 different) Tests Reflexive, Symmetric, Transitive, Consistent, and non-nullity properties of the equals()contract.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Method Detail

      • equalsHashCode

         static <S, T1 extends S, T2 extends S, T3 extends S, T4 extends S> void equalsHashCode(T1 equiv1, T2 equiv2, T3 equiv3, T4 different, boolean requireDistinctHashes)
        Tests Reflexive, Symmetric, Transitive, Consistent, and non-nullity properties of the equals()contract.
        Parameters:
        equiv1 - First equivalent (but unique) object
        equiv2 - Second equivalent (but unique) object (could be a different class)
        equiv3 - Third equivalent (but unique) object (could be a different class)
        different - Non-equivalent object with a (maybe) different hashCode (should be an otherwise compatible class)
        requireDistinctHashes - if true, require that the fourth object have a different hashCode.

      • equalsSameHashCode

         static <S, T1 extends S, T2 extends S, T3 extends S, T4 extends S> void equalsSameHashCode(T1 equiv1, T2 equiv2, T3 equiv3, T4 different)
        Tests Reflexive, Symmetric, Transitive, Consistent, and non-nullity properties of the equals()contract.
        Parameters:
        equiv1 - First equivalent (but unique) object
        equiv2 - Second equivalent (but unique) object (could be a different class)
        equiv3 - Third equivalent (but unique) object (could be a different class)
        different - Non-equivalent object with the same hashCode as the previous three

      • equalsDistinctHashCode

         static <S, T1 extends S, T2 extends S, T3 extends S, T4 extends S> void equalsDistinctHashCode(T1 equiv1, T2 equiv2, T3 equiv3, T4 different)
        Tests Reflexive, Symmetric, Transitive, Consistent, and non-nullity properties of the equals()contract.
        Parameters:
        equiv1 - First equivalent (but unique) object
        equiv2 - Second equivalent (but unique) object (could be a different class)
        equiv3 - Third equivalent (but unique) object (could be a different class)
        different - Non-equivalent object with a different hashCode (should be an otherwise compatible class)