Is there a way in which we can equate two objects?
I know that we can use equals, but the problem is that I need to write a utility which can compare any two objects implementing same interface.
Now the object can have 1 attribute, or 2 attribute or can have 100 attribute. and i need to compare each and every attribute to prove then exactly equal.
You may have a look at the Apache Commons helper classes EqualsBuilder and HashCodeBuilder. These classes provides methods to build good equals and hashCode method for any class.
This can be done using reflection. If you don't want to write your own utility, you can use something like Unitils, which provides a class called ReflectionAssert.
See also Is there a Java reflection utility to do a deep comparison of two objects?
If you don't want to implement equals or a comparator, you can try and do it by reflection.
Iterate over the two objects fields and compare them -
Field[] fields1 = o1.getClass().getDeclaredFields(); Field[] fields2 = o2.getClass().getDeclaredFields(); for (int i = 0; i++ ; i>fields.lenght) { // compare the two fields under the assumption that if the two // objects are the same their fields will be the same in each iteration } use field.get(Object) to retrieve the value of the field
Since there might be nesting and collections of object involved, you'll have to do it recursively for each element, and pointer cycles might present a problem. so if you're expecting cycles you'll have to implement more complex solution (you'll have to store the actual pointers. and check that you are not trying to recursively compare the same elements twice).
