CODEWITHSUNDEEP
javaclassobjectoverridingequals
Ava
Ava

Reputation: 6053

Overriding equals and finding which field was unequal

I am overriding equals method of a class to compare two objects since I want to compare all the fields of it. If two objects are unequal, is there a way to find out which of the fields were unequal due to which the objects are unequal?

Upvotes: 3

Views: 484

Answers (2)

Tkachuk_Evgen
Tkachuk_Evgen

Reputation: 1354

Create class to strore fields information like this (or use Map):

class FieldsContainer<F,V>{
    private F field;
    private V value;
    public FieldsContainer(F field, V value) {
        this.field = field;
        this.value = value;
    }
    public FieldsContainer(){}
    public F getField() {
        return field;
    }
    public void setField(F field) {
        this.field = field;
    }
    public V getValue() {
        return value;
    }
    public void setValue(V value) {
        this.value = value;
    }

}

and then in equals():

public boolean equals(Object obj) {
        ...
        } else if (!field1.equals(other.field1)){
            fieldsContainer=new FieldsContainer("fieldName1", field1);
            return false;
        }
        if (field2 != other.field2){
            fieldsContainer=new FieldsContainer("fieldName2", field2);
            return false;
        }
        fieldsContainer=null;
        return true;
    }

and in main:

if(!obj1.equals(obj2)){
    fieldsContainer.getField();
    fieldsContainer.getValue();
    //Your stuff
}

Upvotes: 0

jamador
jamador

Reputation: 139

You could write a method in the class that returns an object of the same type with either the difference or null for each data member. Or you can find a library that does it for you. Try http://javers.org

Upvotes: 2

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