How do I return Multiple String from loops?

Question

Please take a look at this code (with ArrayList implementation)

public String returnCoreUnitsForProgram()
{
    ArrayList<String> testArray = new ArrayList<String>();

    ProgramClass pc = new ProgramClass("","","","");

    if ( pc.getProgramMajor().equals("Software Technology")
      || pc.getProgramMajor().equals("Network Technology" )
      || pc.getProgramMajor().equals("Games Technology" ) )
    {                           
       for(int i = 0; i< UnitArray.size() ; i++)
       {
            if (UnitArray.get(i).getUnitType().equals("Core"))
                testArray.add( UnitArray.get(i).getUnitName() );
       }                
    }  

    return testArray;
}

With ArrayList - I get the error "imcompatible types"

Without ArrayList:

public void returnCoreUnitsForProgram()
{               
    ProgramClass pc = new ProgramClass("","","","");

    if ( pc.getProgramMajor().equals("Software Technology")
      || pc.getProgramMajor().equals("Network Technology" )
      || pc.getProgramMajor().equals("Games Technology" ) )
    {                           
       for(int i = 0; i< UnitArray.size() ; i++)
       {
            if (UnitArray.get(i).getUnitType().equals("Core"))
            UnitArray.get(i).getUnitName();
       }                
    }                  
}

In another class "ProgramClass",

public String programToString()
{
    Apps apps = new Apps();
    String str = "Program Code: " + getProgramCode()
                +"\nProgram Code: " + getProgramName()
                +"\nProgram Major: "+ getProgramMajor()
                + apps.returnCoreUnitsForProgram();
    return str;
}

I can't possibly do this because returnCoreUnitsForProgram() method is void.

So I'm thinking that my only option is to use the first implementation method with ArrayList.

How can I solve this problem?

of course you have to use the arraylist or an array of strings — Omar NourdeaN
– Omar NourdeaN, Commented May 20, 2014 at 12:28

Evan Knowles · Accepted Answer · 2014-05-20 12:27:04Z

6

You want to return an ArrayList, but you're returning a String. Change the function definition to

public ArrayList<String> returnCoreUnitsForProgram()

Also, you may want to do a lot more reading up on Java core concepts.

answered May 20, 2014 at 12:27

Evan Knowles

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Comments

RVarttinen · Accepted Answer · 2014-05-20 12:33:47Z

In the top most example the method is declared to return a String, while you are attempting to return an ArrayList from the method body. May I suggest that you alter the declaration of the method to return List<String> instead, it should work (compile).

Thus;

public List<String> returnCoreUnitsForProgram(){

    ArrayList<String> testArray = new ArrayList<String>();

    ProgramClass pc = new ProgramClass("","","","");

    if ( pc.getProgramMajor().equals("Software Technology")
      || pc.getProgramMajor().equals("Network Technology" )
      || pc.getProgramMajor().equals("Games Technology" ) )
    {                           
       for(int i = 0; i< UnitArray.size() ; i++)
       {
            if (UnitArray.get(i).getUnitType().equals("Core"))
                testArray.add( UnitArray.get(i).getUnitName() );
       }                
    }  

    return testArray;
}

robinrjoe · Accepted Answer · 2014-05-20 12:41:48Z

1

Try this with Arraylist implementation. Also in your programToString() method , iterate your list and append to String

 public List<String> returnCoreUnitsForProgram()
  {
   ArrayList<String> testArray = new ArrayList<String>();

    ProgramClass pc = new ProgramClass("","","","");

   if ( pc.getProgramMajor().equals("Software Technology")
  || pc.getProgramMajor().equals("Network Technology" )
  || pc.getProgramMajor().equals("Games Technology" ) )
 {                           
   for(int i = 0; i< UnitArray.size() ; i++)
   {
        if (UnitArray.get(i).getUnitType().equals("Core"))
            testArray.add( UnitArray.get(i).getUnitName() );
   }                
}  

return testArray;
}

answered May 20, 2014 at 12:41

robinrjoe

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Comments

Cosmin Spinu · Accepted Answer · 2014-05-20 12:29:14Z

0

Change method type from String to ArrayList<String> :)

answered May 20, 2014 at 12:29

Cosmin Spinu

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