How to Check if every varaible in a Java class contain Null?

Question

I have Set which contain different type of classes like Class A ,Class B,Class C now one class Let us suppose class A have this structure

class A{

String id;
String name;
String password;
 get()/Set() methods 
}

Now Let us suppose Class A each variable contain Null . How to check If class variables contain null so i will not process this class its all DB operation.

Any idea how to separate those classes which all variables are null ?

search in google/[SO](http://stackoverflow.com/questions/4795455/java-how-to-check-for-null-pointers-efficiently). There are many good practices — senseiwu, Apr 11 '14 at 10:31
@Zencv i know What Stackoverflow if you can find answer of this question in Google let me know — JavaBeigner, Apr 11 '14 at 10:35

score 1 · Answer 1 · answered Apr 11 '14 at 10:31

Just define a method isClassEligibleForDBOperations() which returns boolean value and implement it like this.

public boolean isClassEligibleForDBOperations()
{
      if(id != null && name != null && password != null)
      {
            return true;
      }
      return false;
}

Based on the return type you can implement your logic.

score 0 · Answer 2 · answered Apr 11 '14 at 10:50

0

If you are working with JEE6, you can use NOT NULL annotation javax.validation.constraints.NotNull. Otherwise you can implement your own NOT NULL annotation and use it.

answered Apr 11 '14 at 10:50

Shahnaz Khan

1,055
1
14
26

I am using Java7 any example you have about javax.validation.constraints.NotNull. – JavaBeigner Apr 11 '14 at 10:52

score 0 · Answer 3 · answered Apr 11 '14 at 11:32

Is there any constructor in these classes? As I don't see any and you are asking for class variables I'd guess its static variable. Than you can check really easy:

if(A.variable == null){ 
  // your functions
}

or

@class A
String getVariable(){
  return variable;
}

@anywhere
if(A.getVariable() == null){ 
  // your functions
}

And I hope "variable contains Null" means it's content is null

How to Check if every varaible in a Java class contain Null?

3 Answers3