What is the use of encapsulation when I'm able to change the property values with setter methods?

Question

I try to understand a lot of times but I failed to understand this.

Encapsulation is the technique of making the fields in a class private and provi

Answer 1

The main idea behind encapsulation is data hiding. There are several reasons why we use encapsulation in object oriented programming. Some of the identified reasons for why we encapsulation are as follows (The real use of encapsulation).

1. Better maintainability: When all the properties are private and encapsulated, it is easy for us to maintain the program simply by changing the methods.

2. Make Debugging Easy: This is in line with the above point. We know that the object can only be manipulated through methods. So, this makes it easy to debug and catch bugs.

3. Have a Controlled Environment: Let the users use the given objects, in a controlled manner, through objects.

4. Hide Complexities: Hiding the complexities irrelevant to the users. Sometimes, some properties and methods are only for internal use and the user doesn't have to know about these. This makes is simple for the user to use the object.

So, to answer the question, "What is the use of encapsulation when I'm able to change the property values with setter methods?", given above are some of the main reasons why we use encapsulation. To provide an understanding on why, getters and setters are useful, given below are some important points, obtained from this article.

• You can limit the values that can be stored in a field (i.e. gender must be F or M).

• You can take actions when the field is modified (trigger event, validate, etc).

• You can provide thread safety by synchronizing the method.

• You can switch to a new data representation (i.e. calculated fields, different data type)

Answer 2

The real use of encapsulation is also in the fact that you can do additional checks/processing on the way the values are set.

Answer 3

You're not exactly preventing access to the fields -- you're controlling how others can access certain fields. For example you can add validation to your setter method, or you can also update some other dependent field when the setter method of a field is called.

You can prevent write or read access to the field (e.g. by only providing a getter or setter respectively) -- but encapsulation with properties allows you to do more than just that.

Answer 4

Encapsultaion is used for hiding the member variables ,by making member as private and access that member variable by getter and setter methods.

Example

class Encapsulation{

private int value ;

Encapsulation() {
    System.out.println("constructor calling ");
}

void setValue(int value){
    this.value = value;
}
int getValue() {
    return value;
}

} class EncapsulationMain {

public static void main(String args[]) {
    Encapsulation obj = new Encapsulation();
    obj.setValue(4);
    //System.out.print("value is "+obj.value); 
    //obj.value = 55;
    //System.out.print("obj changing the value"+obj.value);
    System.out.print("calling the value through the getterMethod"+obj.getValue());
}

}

you cannot access the private value outside the class.

Answer 5

By using encapsulation you separate your class from the out-side world (other classes) and out-side world can access and modify your class instance variables through access modifiers, which provides several benefits:

-You can do some logging in your getter/setter methods.

-You can validate /normalize (for example trim spaces, remove special character,...) Your input in setter method.

And also you can hide your implementation from the outside world, for example you have a collection like array list in your class and you write your getter method like this

public List<t> get collection(){
 return new  ArrayList<t>(this.arrayList);
}

So in this case, in the future if you decide to change your implementation of collection from array list to something else like linked list, you are free to do so because out side world doesn't know anything about your implementation.

Answer 6

Instead of letting everyone access the variables directly:

public Object object;

Is better to use SET and GET methods, or for example just the GET method (Sometimes you dont want nobody to set other value to that variable).

public Object getObject() { 

return object;
}

public void setObject(Object object) { 

this.object = object;
}