package votorola.a.count; // Copyright 2013, Michael Allan.  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Votorola Software"), to deal in the Votorola Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicence, and/or sell copies of the Votorola Software, and to permit persons to whom the Votorola Software is furnished to do so, subject to the following conditions: The preceding copyright notice and this permission notice shall be included in all copies or substantial portions of the Votorola Software. THE VOTOROLA SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE VOTOROLA SOFTWARE OR THE USE OR OTHER DEALINGS IN THE VOTOROLA SOFTWARE.

import votorola.a.*;
import votorola.g.*;
import votorola.g.lang.*;


/** A count source that caches a single count.
  */
public final class CountSource1 implements CountSource
{


    /** Constructs a CountSource1.
      *
      *     @see #vsRun()
      */
    public CountSource1( VoteServer.Run _vsRun ) { vsRun = _vsRun; }



   // ------------------------------------------------------------------------------------


    /** The ultimate source of the count.
      */
    public final VoteServer.Run vsRun() { return vsRun; }


        private final VoteServer.Run vsRun;



   // - C o u n t - S o u r c e ----------------------------------------------------------


    /** @throws IllegalArgumentException if a count was previously requested by this
      *   method under a different poll name.
      */
    public Count count( final String pollName )
    {
        if( pollNameRequested == null )
        {
            try{ count = vsRun.scopePoll().ensurePoll(pollName).countToReportT(); }
            catch( java.io.IOException|javax.script.ScriptException|java.sql.SQLException x )
            {
                throw new VotorolaRuntimeException( x );
            }

            pollNameRequested = pollName; // fetch attempted once only
        }
        if( count == null || pollName.equals(count.pollName()) ) return count;

        throw new IllegalArgumentException( pollName + " requested but count already cached for "
          + count.pollName() );
    }



//// P r i v a t e ///////////////////////////////////////////////////////////////////////


    private Count count; // lazily fetched to save the effort



    private String pollNameRequested;


}