Package org.apache.commons.lang3.builder

Interface Diffable<T>

  • Type Parameters:
    T - the type of objects that this object may be differentiated against
    Functional Interface:
    This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
    @FunctionalInterface
public interface Diffable<T>

    Diffable classes can be compared with other objects for differences. The DiffResult object retrieved can be queried for a list of differences or printed using the DiffResult.toString().

    The calculation of the differences is consistent with equals if and only if d1.equals(d2) implies d1.diff(d2) == "". It is strongly recommended that implementations are consistent with equals to avoid confusion. Note that null is not an instance of any class and d1.diff(null) should throw a NullPointerException.

    Diffable classes lend themselves well to unit testing, in which a easily readable description of the differences between an anticipated result and an actual result can be retrieved. For example: 

     Assert.assertEquals(expected.diff(result), expected, result);
    Since:
    3.3

    • Method Detail

      • diff

        DiffResult<T> diff​(T obj)

        Retrieves a list of the differences between this object and the supplied object.

        Parameters:
        obj - the object to diff against, can be null
        Returns:
        a list of differences
        Throws:
        java.lang.NullPointerException - if the specified object is null