dynamic object identification problem

[clownie]

ok, I have a class that takes 3 inputs.
Variable(NAME, TYPE, DATA);
the name is a string, the type is a string, however the DATA is where it gets tricky.

DATA depends on what the string TYPE is. Example
if TYPE is a String
DATA isa String
if TYPE is a VectorObject
DATA isa VectorObject

you get the idea right?
Now, here's the problem. I don't know what to identify DATA as. It's type is determined at runtime, not compiletime, so I don't know what to define it as, since a string cannot be coverted into VectorObject, plus i can't keep redefining DATA.
Example:
if TYPE isa VectorObject
DATA isa VectorObject
would be shown as VectorObject DATA = new VectorObject();
the problem arises when i try to store or return the DATA object!

public <omg i dont know what identifier goes here, b/c i don't know the type yet> GetData { return DATA;}

There's got to be a better way to do this or something small that im missing.
like an interface.. but i dont know how to implment the interface if so....

[Phaelax]

Desfine data as Object

if (data instanceof String)
    String s = (String)data;
else if(data instanceof Vector)
    Vector v = (Vector)data;

Not sure what you're wanting to do here, but it doesn't sound like a very good way of doing it. I could help you more if you tell me how those objects are going to be used.

[clownie]

here's the problem tho, when i go to define data it keep *****ing for an identifier!
like (keep in mind im a c programmer) i cant do
public void data;
and if i give it a type when i create data variable i have to cast, (which i said i can't do with vector)
So basically i'm really asking how do i make a variable with no type, then GIVE it a type later...

this is for ascripting system.
I read in a file with:

varName varType varData

then i pass those values to Variable class to store them.
I make an arraylist of variable objects to keep track of all the variables in the file.

but in the Variable(name,type,data) class i need to establish the correct data values.
If the type in the file says "vector" or"float" i know the value is a vector or float.
However when i declare a variable "Data" i don't know what type (int,string,vector,float) to make it when i declare it.
I'd have to make it return a string constantly, then parse the string to see if it's the correct type...

So i eithr have to keep creating different instances of a varibale data or just make one instance and have it a void type which i thought id be able to cast or change into the needed type later...


also a problem arises when i attempt to return the varData value. Since i wont know what type it is at compile time i wont know what to return!
would i do as you said, and justdo

if data instanceOf vector
return vectored data;
if data instanceOf float
return floated data;

but, how do i make data a float or vector dynamically like that(since a string or other type wont cast correctly to a vector...)?
and how do i know what to make the return type for the method that returns the data variable value.

public String GetData(){}//isn't right if data is a vector, b/c it should return a vector object... not a string.
public void GetData(){} //wont let me return something... or will it?
is that slightly more clear? if you'd like to see the classes, please let me know.
Basically is there a way to make a variable without a type at compile time? then just have it "casted" (for lack of a better term) at runtime with the proper datatype?

[clownie]

script class

 import java.io.*;
 import java.util.ArrayList;
 public class Script
 {
 	public ArrayList<Variable> variables = new ArrayList<Variable>();//make this array list global? or just return it?
 	
 	public Script(String fileName, String path)
 		{
 			if (fileName==null)
 				return;
 			
 			String   line;
 			String[] lineSplit;
 			
 			//ArrayList file = new ArrayList(); -- not needed? use normal string array instead?
 			try
 			{
 				boolean read=false;//true when you should start reading for variables. false when encounters #end or doesn't find #begin
 				BufferedReader in = new BufferedReader(new FileReader(fileName));
 				
 				if(!in.ready()) throw new IOException();
 				//MAIN SCRIPT READING&PROCESSING HERE
 				while(in.readLine() != null)
 				{
 					line=in.readLine();
 					//split up line into tokens
 					lineSplit = line.split(" ");
 					//before for loops so next line gets read in by while loop, since after a #begin the next line must be a variable declaration
 					if(read==true)
 					{
 						if(lineSplit[0].equals("#end"))
 							read=false; 
 						else
 						{
 							variables.add(new Variable(lineSplit[0],lineSplit[1],lineSplit[2]));//name, type, value or just pass lineSplit
 							System.out.println("Added new Variable: "+lineSplit[0]+" "+lineSplit[1]+" "+lineSplit[2]);
 						}	
 							/*Variable() is going to need to be able to differentiate b/t types and then alter it's own
 							 *data based on its type.
 							 *Example: 
 							 *if type is Vector 3D 
 							 *split up the value into it's 3 xyz components.
 							 *store the new value as a Vector3D object.
 							 *varvalue=new Vector3D(x,y,z); or 
 							 *varvalue=new Vector3D;
 							 *varvalue.x=x;
 							 *varvalue.y=y;
 							 *varvalue.z=z; 
 							 *you get the idea.
 							 */
 					}//endif
 					
 					//check token for beginning of variables -- #begin and #end should be on own line to simplify reading. Can take out the for loops and just put 0 in place of i.
 					for(int i=0; i<lineSplit.length;i++)
 						if(lineSplit[i].equals("#begin")) 
 							read=true;
 					
 					for(int i=0; i<lineSplit.length;i++)
 						if(lineSplit[i].equals("#end")) 
 							read=false;
 					
 					line=null;		
 				}//endwhile

 				in.close();
 			}catch(IOException e)
 			{
 				System.out.println(e);
 				return;
 			}
 			
 				
 		}
 		
 	/*	void addVariable(){}
 		void setVariable(){} //return a variable's value with specified name
 		
 		boolean getBoolData(){}
 		float getFloatData(){}
 		Color getColorData(){}
 		Vector3D getVectorData(){}
 		String getStringData(){}
 		double getNumberData(){}
 	*/
 }

variable class

public class Variable
{
		private String varname; //Name of variable.
		private String vartype; //type of value (float,bool, etc).
		private String varvalue;  //Data stored in variable.
		
	public Variable(String name, String type, String value)
		{
			varname=name;
			//check types
			if(type.equals("bool"))
			{
				//variable is a boolean
				vartype=type;
				boolean varvalue=Boolean.parseBoolean(value);
				//check to see if true or false
			}
			else if(type.equals("float"))
			{
				vartype=type;
				float varvalue=Float.parseFloat(value); 
				
			}
			else if(type.equals("string"))
			{
				vartype=type;
				varvalue=value;
			}
			else if(type.equals("color"))
			{
								//take care of color Color3D (r,g,b,Alpha)
			}
			else if(type.equals("vector"))
			{
								//take care of Vector3D split the value with commma as delimiter	
			}			
			else if(type.equals("point"))
			{
								//take care of Point3D split value with comma as delimeter
			}
			else //type=unknown... so ignore it...
			{
				
			}
						
		}	
		public String GetType(){ return vartype;}
		public String GetName(){ return varname;}
		public String GetStringData(){ return varvalue;}
}

[Phaelax]

you can't create a void data type, void is more for the return type of a method that returns nothing. I don't know of any way to do what you want.

[clownie]

alright, thanks anyways. found the solution i was looking for anyways.

[destin]

Umm... you could have just done what Phaelax said.

class MyClass {
    private Object data;

    public MyClass( Object thing ) {
        data = thing;
    }
    public Object getData() {
        return data;
    }
}

and if you did this:

MyClass test = new MyClass( new Integer( 5 ));
System.out.println( test.getData() );

test = new MyClass( new String( "hi" ));
System.out.println( test.getData() );

that would print:

5
hi