java.lang.Field equivalent in c++

Question

I have a code that uses Field built in function in java and i could not find a way to replace it in c++ the code is shown below,

import java.lang.reflect.Field; 
 
public class ParameterValue { 
    public String objectPath; 
    public Object objectReference; 
    public String fieldPath; 
    public String fieldPathNoCase; 
    public Field field; 
 public double value; 
  
 public ParameterValue(String path, ObjectTree tree, Field fieldInfo) { 
  objectPath = path; 
  objectReference = tree.getObject(path); 
  field = fieldInfo; 
  fieldPath = objectPath + "." + field.getName(); 
  fieldPathNoCase = fieldPath.toLowerCase();  
  read(); 
 } 
 
 public int getPrecision() { 
if (field.getType().getName() == "float" || field.getType().getName() == "double") 
   return 2; 
  else 
   return 0; 
 } 
  
 public double getPrecisionMultiplier() { 
  return Math.pow(10, getPrecision()); 
 } 
  
 public void read() { 
  String type = field.getType().getName(); 
  try { 
   if (type.equals("double")) 
    value = field.getDouble(objectReference); 
   else if (type.equals("float")) 
    value = field.getFloat(objectReference); 
   else if (type.equals("int")) 
    value = field.getInt(objectReference); 
   else if (type.equals("byte")) 
    value = field.getByte(objectReference); 
   else 
    throw new RuntimeException(); 
  } catch (IllegalAccessException e) { 
   throw new RuntimeException(e); 
  } 
  value = Math.round(value * getPrecisionMultiplier()) / getPrecisionMultiplier(); 
 } 
  
 public void write() { 
  String type = field.getType().getName(); 
  try { 
   if (type.equals("double")) 
    field.setDouble(objectReference, value); 
   else if (type.equals("float")) 
    field.setFloat(objectReference, (float)value); 
   else if (type.equals("int")) 
    field.setInt(objectReference, (int)Math.round(value)); 
   else if (type.equals("byte")) 
    field.setByte(objectReference, (byte)Math.round(value)); 
   else 
    throw new RuntimeException(); 
  } catch (IllegalAccessException e) { 
   throw new RuntimeException(e); 
  } 
 } 
  
 public void rebind(ObjectTree tree) { 
  objectReference = tree.getObject(objectPath); 
 } 
}

What i have understood from the code is that i need to find a class that can convert the value in it to Double, Float,etc. I have looked for something that can do this but i was not able to do so. reference of the code: https://www.programcreek.com/java-api-examples/index.php?source_dir=SecugenPlugin-master/src/sourceafis/simple/Fingerprint.java#

There is no equivalent. C++ doesn't have reflections. You might be able to do something similar with some variant. — Jaa-c, Apr 17 '18 at 11:57
@Jaa-c, not strictly true, there [are solutions](https://stackoverflow.com/questions/41453/how-can-i-add-reflection-to-a-c-application), just not out of the box ones. — M. Prokhorov, Apr 17 '18 at 11:59
There is no equivalent as there can't be an equivalent. Those are two completely different programming languages. — Ron, Apr 17 '18 at 12:03
@M.Prokhorov your linked solutions are they made classes that i can use in order to get the same result in field? — A M A, Apr 17 '18 at 12:06
@AMA, I don't understand this question. What does "they made classes" mean? Have you read any details on solutions that I've linked? — M. Prokhorov, Apr 17 '18 at 12:34
@M.Prokhorov what i understood is that they are trying to implement their own field class — A M A, Apr 17 '18 at 13:21

score 1 · Accepted Answer · answered Apr 17 '18 at 12:06

1

As per my knowledge there is no equivalent class in C++. Now for your requirement first you list out what are all a java.lang.reflect.Field class provides in java. Once you listed all the utility methods, just sort list all methods that you really requires in your C++ application. Once done you do create a C++ class with the same name and methods types and implement the logic by yourself if possible.

answered Apr 17 '18 at 12:06

Abhijit Pritam Dutta

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You can't just implement reflections by yourself. That's a language feature, not something you implement. You need totally different logic to achieve similar goal in C++. – Jaa-c Apr 17 '18 at 12:41
I was able to create a Field class that serves my SDK and it runs fine. Thank you for the idea. – A M A Apr 17 '18 at 13:22

java.lang.Field equivalent in c++

1 Answers1