Java Reflection - how to set value for the class which are extended from One and Two

Question

Goal :

set the value for a class fields as well the extended class fields

Example :

public class CreateRequisitionRO extends AbstractPortfolioSpecificRO {....}

i am able to set value for the CreateRequisitionRO but not able to set value for AbstractPortfolioSpecificRO which is being extended.

This is how i set the value :

public Object creatObjectWithDefaultValue(String className) throws IllegalArgumentException, IllegalAccessException, InstantiationException {
        Class<?> objectClass = null;
        Object clsObject =null;
        try {
            objectClass = Class.forName(className);
            clsObject = objectClass.newInstance();
             Field[] fields = objectClass.getDeclaredFields();
             for(Field f:fields){
                  if(!f.isAccessible()){
                        f.setAccessible(true);
                        Class<?> type = f.getType();
                        if(! Modifier.isFinal(f.getModifiers()) && type.equals(Integer.class)){
                            f.set(clsObject, DefaultParamValuesEnum.INTEGER.getDefaultInt());  
                        } else if( !Modifier.isFinal(f.getModifiers()) && type.equals(java.math.BigDecimal.class)){
                            f.set(clsObject, DefaultParamValuesEnum.BIGDECIMAL.getDdefaultBigDecimal());  
                        } else if(! Modifier.isFinal(f.getModifiers()) && type.equals(org.joda.time.LocalDate.class)){
                            f.set(clsObject,DefaultParamValuesEnum.DATE.getDefaultDate());  
                        }  else if(! Modifier.isFinal(f.getModifiers()) && type.equals(boolean.class)){
                            f.set(clsObject, DefaultParamValuesEnum.BOOLEAN.getDefaultBoolean());  
                        } else if(! Modifier.isFinal(f.getModifiers()) && type.equals(java.lang.String.class)){
                            f.set(clsObject, DefaultParamValuesEnum.STRING.getDefaultString());  
                        }
                        else if(! Modifier.isFinal(f.getModifiers()) && type.equals(long.class)){
                            f.set(clsObject,DefaultParamValuesEnum.LONGVALUE.getDefaultLong());  
                        }
                     }
               }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return clsObject;
    }

This is how i call the above method :

classObject.creatJSONObject("com.hexgen.ro.request.CreateRequisitionRO");

The above way sets value for all the fields available in CreateRequisitionRO not fields which are available in extended class.

How to set it?

you should wrap this check around the other checks: `if(! Modifier.isFinal(f.getModifiers()))` instead of doing the same check over and over again — Sean Patrick Floyd, Apr 30 '13 at 09:29

score 1 · Answer 1 · answered Apr 30 '13 at 09:01

1

You can get super class of your class using Class<SuperClass> superClazz = clazz.getSuperclass();

Once got, get the Field[] using superClazz.getFields() and use set method of Field

answered Apr 30 '13 at 09:01

sanbhat

17,522
6
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score 1 · Answer 2 · answered Apr 30 '13 at 09:01

1

Use getSuperclass() method to obtain the class object of superclass. and then in the similar way get the fields of superclass.

answered Apr 30 '13 at 09:01

Vineet Singla

1,609
2
20
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score 1 · Accepted Answer · answered Apr 30 '13 at 09:08

You can use clazz.getSuperclass() to retrieve the supertype of CreateRequisitionRO. Once you have a handle on the supertype AbstractPortfolioSpecificRO you can iterate its fields. I would recommend storing all of these fields in a List<Field>. Iterate through this list and set the fields based upon your conditional logic.

I have provided a quick example of how to perform this. In my example, Child extends Parent. The recursive getFields method returns a List<Field> that contains all of the fields for Child. I then iterate through the List<Field> setting the value for each one. Notice that I must switch the accessibility of private fields.

Child.Java

public class Child extends Parent {
    public String a;
    public String b;


    public static void main(String[] args) throws IllegalArgumentException, IllegalAccessException {
        Child child = new Child();
        List<Field> fields = getFields(child.getClass());

        for(Field f: fields){
            f.setAccessible(true);
            f.set(child, "Test");
        }

        for(Field fd: fields){
            System.out.println(fd.get(child));
            fd.setAccessible(false);
        }


    }

    public static List<Field> getFields(Class<?> clazz){
        List<Field> list = new ArrayList<Field>();
        list.addAll(Arrays.asList(clazz.getDeclaredFields()));

        if(clazz.getSuperclass() != null){
            list.addAll(getFields(clazz.getSuperclass()));
        }
        return list;
    }
}

Parent.java

public class Parent {
    private String x;
    public String y;
    protected String z;

}

Thanks for the nice explanation +1. will do this and mark this as answer as this will help others too. — Java Questions, Apr 30 '13 at 09:17
@Anto Glad I could help. If you have any further questions let me know. — Kevin Bowersox, Apr 30 '13 at 09:18
Kevin i get only field name like the following `userId` when i use `getSuperclass().` but i need to get like `private java.lang.String com.hexgen.ro.request.CreateRequisitionRO.custodianN` is it possible — Java Questions, Apr 30 '13 at 09:51
let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/29183/discussion-between-anto-and-kevin-bowersox) — Java Questions, Apr 30 '13 at 10:00

score 0 · Answer 4 · edited May 23 '17 at 12:04

0

obj.getClass().getSuperclass().getDeclaredFields();

you can use above function for achieving same ..

also check Access to private inherited fields via reflection in Java

edited May 23 '17 at 12:04

Community

1
1

answered Apr 30 '13 at 09:02

ManMohan Vyas

4,004
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Java Reflection - how to set value for the class which are extended from One and Two

4 Answers4