Diffable

@FunctionalInterface public abstract interface org.apache.commons.lang3.builder.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);

Parameters:

<T> – The type of objects that this object may be differentiated against

Since:

3.3

Methods

diff(Object)

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

public abstract 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 – Thrown if the specified object is null.