//
//  QueryObject.java
//
//  WELD Java Client Persistent Object Management Package
//  Copyright Francis Chan (fchan@ic.eecs.berkeley.edu), 1997
//  University of California, Berkeley
//
//
//  This program is in the public domain.
//  Permission to use, copy, modify, and distribute this software
//  and its documentation for NON-COMMERCIAL purposes and
//  without fee is hereby granted, as long as credit is given.

import java.util.Vector;
import java.io.StreamTokenizer;

/**
 *
 * QueryObject Class
 *
 * This is a class which is used to query data at a remote server 
 * (extends PersistentObject only to take advantage of the built-in
 *  network capabilities.  Not meant to be saved or loaded.)
 *
 * @version 1.1 February 1997
 * @author  Francis Chan
 */

public class QueryObject extends PersistentObject{

  // Query Scope options

  public static final int GLOBAL = 0;
  public static final int CLASS = 1;
  public static final int DATABASE = 2; // or container

  double[] queryIdArray;

  private Vector objVector;

  /**
   * Constructor for QueryObject
   */
  public QueryObject(){

  }

  /** 
   * Executes the query requested
   *
   */
  public int execQuery(String userId, String objectClassName, 
		       int scope, String fieldName, String strId){
    
    if (connectServer() == false)
      return PO.ERROR;

    outStreamString = comCons.prepareQueryCommandString(PO.QUERY, userId,
							objectClassName,
							scope,
							fieldName, strId);

    send(outStreamString);
    objVector = parse(PO.QUERY);
    netClient.closeConnection(netSocket);
    
    return PO.OK;
  }

  protected Vector parseQuery(StreamTokenizer strToke){

    Vector infoVector = new Vector();
    int token;
    int numContents;

    try {
      token = strToke.nextToken();

      if (parseNumber(strToke, "Number (of contents) expected!") != true){
	return null;
      }
      numContents = (int) strToke.nval;

      for (int i=0; i<numContents; i++){
      
	String className;
	int id;

	className = parseForWord(strToke, "Class Name expected");
	if (className == null)
	  return null;

	token = strToke.nextToken();
	if (parseNumber(strToke, "Id expected!") != true){
	  return null;
	}
	id = (int) strToke.nval;

DEBUG("The pair are :" + className + id);

	PO_ObjectInfo objInfo = new PO_ObjectInfo(className, null, id);
	infoVector.addElement(objInfo);
      }
    } catch (Exception e){
      System.out.println("Parse problems with parseQuery!");
      return null;
    }

    return infoVector;    

    /*
    queryIdArray = parseArray(strToke);

    // for debugging
    for (int i=0; i<3; i++){
      System.out.println(i + "'s value is: " + queryIdArray[i]);
    }
    return queryIdArray;
    */
  }

  /*-----------------------------------------------------------
   * The code below is required for extending PersistentObject
   * (should not be called)
   *-----------------------------------------------------------*/

  protected void setObjFields() {
  }

  protected void getObjFields() {
  }
}