/* Directory.java 1.0                       */
/* by Sharon Tuttle                         */
/* last modified: 2-18-03                   */

class Directory
{
    /*--------------------------
     fields
     ----------------------------*/
 
    /* the FIRST element in the directory */
    DirectoryElement first;

    /* how many are IN the directory instance right now? */
    int count;

    /*------------------------------
     constructors
     --------------------------------*/
    
    /* create an empty Directory object */
    Directory()
    {
        this.first = null;
        this.count = 0;
    }

    /* create a Directory containing just a single entry */
    Directory(CityEntry entry)
    {
        this.first = new DirectoryElement(entry);

        this.count = 1;
    }

    /*----------------------------------
     accessors
     ------------------------------------*/
    DirectoryElement getFirst()
    {
        return this.first;
    }

    int getCount()
    {
        return this.count;
    }

    /*-----------------------------------------------------
     overridden methods 
     --------------------------------------------------------*/
    public String toString()
    {
        if (this.count == 0)
        {
            return "Directory[]";
        }
        else
        {
            return "Directory[\n" +
                   printAllInDir(this.first) + "]";
        }        
    }

    /*---------------------------------------
     other methods
     ----------------------------------------*/
    /*-------------------------------------------------------------
     printAllInDir()
     Purpose: a helper method for toString, to help it in depicting
              all of the CityEntry's in a Directory.
     (deliberately made private --- for "local" class use only!)
    ----------------------------------------------------------------*/                    
    private String printAllInDir(DirectoryElement curr)
    {
        if (curr != null)
        {
            return curr.dirEntry + "\n" +
                   printAllInDir(curr.nextInDirectory);
        }
        else
        {
            return "";
        }
    }

    /*------------------------------------------------------------
     addToBeginning
     Purpose: make CityEntry entry the first element in the calling
              Directory instance.
    ---------------------------------------------------------------*/
    void addToBeginning(CityEntry entry)
    {
        DirectoryElement newDirElem = new DirectoryElement(entry);

        /* new element is in front of CURRENT first element */
        newDirElem.setNextInDirectory(this.first);

        /* new element should now be FIRST in directory */
        this.first = newDirElem;
        
        /* and, of course, count in directory must be increased! */
        this.count = this.count + 1;
    }
}