java - Base class does not define equals but sub-class needs to. How to implement? -


i don't have access base class code. need able define equals in sub-class take base class properties consideration.

additionally base class not have protected fields. fields accessible through accessors/mutators.

would considered bad comparisions of base class fields in sub-class equals ? why ?

i need because base class has default equals not work purpose has fields need taken consideration when doing sub-class equals...

yes, can this, there won't problems calling getters in superclass can determine equality way want, long follow contract:

reflexive: x.equals(x) should return true.

symmetric: x.equals(y) == y.equals(x)

transitive: x.equals(y) && y.equals(z) => x.equals(z)

consistent: multiple invocations of x.equals(y) consistently return true or false unless x or y mutated between calls.

and equals-hashcode contract:

equal objects must have equal hashcodes

http://download.oracle.com/javase/6/docs/api/java/lang/object.html#equals(java.lang.object)


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