ZUtils.java

/*
 * This file is part of Zql.
 *
 * Zql is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Zql is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Zql.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.gibello.zql;

import java.util.Hashtable;

public class ZUtils {

  private static Hashtable fcts_ = null;

  public static final int VARIABLE_PLIST = 10000;

  public static void addCustomFunction(String fct, int nparm) {
    if(fcts_ == null) fcts_ = new Hashtable();
    if(nparm < 0) nparm = 1;
    fcts_.put(fct.toUpperCase(), new Integer(nparm));
  }

  public static int isCustomFunction(String fct) {
    Integer nparm;
    if(fct == null || fct.length()<1 || fcts_ == null
      || (nparm = (Integer)fcts_.get(fct.toUpperCase())) == null)
       return -1;
    return nparm.intValue();
  }

  public static boolean isAggregate(String op) {
    String tmp = op.toUpperCase().trim();
    return tmp.equals("SUM") || tmp.equals("AVG")
        || tmp.equals("MAX") || tmp.equals("MIN")
        || tmp.equals("COUNT") || (fcts_ != null && fcts_.get(tmp) != null);
  }

  public static String getAggregateCall(String c) {
    int pos = c.indexOf('(');
    if(pos <= 0) return null;
    String call = c.substring(0,pos);
    if(ZUtils.isAggregate(call)) return call.trim();
    else return null;
  }

};