package bluej.debugmgr;

import threadchecker.OnThread;
import threadchecker.Tag;




| A history of Strings that maintains an internal cursor to provide
| 'getNext'/'getPrevious'-style methods to traverse the history list.
|
| @author mik
|
@OnThread(Tag.Any)
public class IndexHistory
extends History {

   
private int currentIndex;
    
   



|
| @param maxLength Number of entries in history list
|
public IndexHistory(int maxLength)
   {
   super(maxLength, true);
       
   currentIndex = 0;     
   }
    
   



| Add a string to the history of used strings.
|
| @param newString  the new string to add
|
public void add(String newString)
   {
   super.add(newString);
       
   currentIndex = 0;     
   }
    
   



| Get the previous history entry. Calling this repeatedly walks
| back through the history
|
| @return The previous history entry.
|
public String getPrevious()
   {
   if (currentIndex+1 < history.size()) {            
      currentIndex++;
      return (String) history.get(currentIndex);         
      }
       

   else {
           
   return null;         
   }     
}

   



| Get the next history entry. Calling this repeatedly walks
| forward through the history
|
| @return The next history entry.
|
public String getNext()
   {
   if (currentIndex > 0) {            
      currentIndex--;
      return (String) history.get(currentIndex);         
      }
       

   else {
           
   return null;         
   }     
} 
}