Java Reflection Utils

ReflectionUtils.java

import java.lang.reflect.Field;

public class ReflectionUtils {

    public static <T> T getOrDefault(T object, String propertyName, Class<T> clazz, T defaultValue) {
        try {
            // Get the field by name
            Field field = object.getClass().getDeclaredField(propertyName);
            
            // Ensure field is accessible
            field.setAccessible(true);
            
            // Get the value of the field
            Object value = field.get(object);
            
            // Check if the value is null, return default value if null
            if (value == null) {
                return defaultValue;
            }
            
            // Check if the value is of the correct type, otherwise return default value
            if (clazz.isInstance(value)) {
                return clazz.cast(value);
            } else {
                return defaultValue;
            }
        } catch (NoSuchFieldException | IllegalAccessException | ClassCastException e) {
            // In case of any exception, return default value
            return defaultValue;
        }
    }

    public static void main(String[] args) {
        // Example usage
        MyClass myObject = new MyClass();
        String result = getOrDefault(myObject, "myString", String.class, "defaultString");
        System.out.println(result); // This will print the value of myString if it exists, otherwise "defaultString"
    }
}

class MyClass {
    private String myString = "Hello";
}