Question

Im getting class name (string) and the class have few sets method and
since Its dynamic (I can get any class) I need to use all the sets method and update it with data .
how can I do that ?

To get the class field I’m using the following code

className = obj.getClassName();
Class<?> classHandle = Class.forName(className);

for example here I need to update firstName and last name

public class Person {

private String id;
    private String firstName;
    private String lastName;

    public void setLastName(String lastName) {

        this.lastName = lastName;
    }

    public void setfirstName(String firstName) {

        this.firstName = firstName;
    }

or different class here i need to set the salary and the job description

public class Job {


  private double salery;
  private String jobDescr;


  public void setSalery(double salery) {
    this.salery = salery;
  }

  public void setJobDescr(String jobDescr) {
    this.jobDescr = jobDescr;
  }

}

Answer 1

For starters, What you’ve done is good. I assume you have a Map<String, Object> of the attributes to be set: attributeMap.

//this is OK
className = obj.getClassName();
Class<?> classHandle = Class.forName(className);

//got the class, create an instance - no-args constructor needed!
Object myObject = classHandle.newInstance();

//iterate through all the methods declared by the class  
for(Method method : classHandle.getMethods()) {
   //check method name
   if(method.getName().matches("set[A-Z].*") 
       //check if it awaits for exactly one parameter
       && method.getParameterTypes().length==1) {

       String attributeName = getAttributeName(method.getName());
       //getAttributeName would chop the "set", and lowercase the first char of the name of the method (left out for clarity)

       //To be extra nice, type checks could be inserted here...
       method.invoke(myObject, attributeMap.get(attributeName));            

   }
}

Of course, a lot of exception handling is to be done, this is just a basic idea of what is to be done…

Recommended reading:

• Class
• Class.getMethods()
• Method
• Method.invoke()