DateElementDiff.java :  » Scripting » Pnuts » org » pnuts » lib » Java Open Source

/*
 * @(#)DateElementDiff.java 1.3 05/05/07
 *
 * Copyright (c) 1997-2004 Sun Microsystems, Inc. All Rights Reserved.
 *
 * See the file "LICENSE.txt" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 */
package org.pnuts.lib;

import java.util.Date;
import java.util.Calendar;
import pnuts.lang.PnutsFunction;
import pnuts.lang.Context;

class DateElementDiff extends PnutsFunction {
  private int element;

  DateElementDiff(int element, String name){
    super(name);
    this.element = element;
  }

  public boolean defined(int nargs){
    return nargs == 2;
  }

  static int diffYear(Calendar c0, Calendar c1){
    return c1.get(Calendar.YEAR) - c0.get(Calendar.YEAR);
  }

  static int diffMonth(Calendar c0, Calendar c1){
    return diffYear(c1, c0) * 12 + c1.get(Calendar.MONTH) - c0.get(Calendar.MONTH);
  }

  static int diffHour(Calendar c0, Calendar c1){
    return diffDay(c0, c1) * 24 + c1.get(Calendar.HOUR_OF_DAY) - c0.get(Calendar.HOUR_OF_DAY);
  }

  static int diffMinute(Calendar c0, Calendar c1){
    return diffHour(c0, c1) * 60 + c1.get(Calendar.MINUTE) - c0.get(Calendar.MINUTE);
  }

  static long diffSecond(Calendar c0, Calendar c1){
    return diffMinute(c0, c1) * 60L + c1.get(Calendar.SECOND) - c0.get(Calendar.SECOND);
  }  

  static long diffMilliSecond(Calendar c0, Calendar c1){
    return diffSecond(c0, c1) * 1000L + c1.get(Calendar.MILLISECOND) - c0.get(Calendar.MILLISECOND);
  }  

  static int diffDay(Calendar c0, Calendar c1){
    int year0, year1;
    int day0, day1;
    year0 = c0.get(Calendar.YEAR);
    day0 = c0.get(Calendar.DAY_OF_YEAR);
    year1 = c1.get(Calendar.YEAR);
    day1 = c1.get(Calendar.DAY_OF_YEAR);

    if (year0 == year1) {
      return day1 - day0;
    } else {
      boolean negative;
      if (year0 > year1){
        int tmp = year0;
        year0 = year1;
        year1 = tmp;
        tmp = day0;
        day0 = day1;
        day1 = tmp;
        negative = true;
      } else {
        negative = false;
      }
      int days;
      Calendar c = (Calendar)c0.clone();
      c.set(year0, 11, 31);
      days = c.get(Calendar.DAY_OF_YEAR) - day0;
      for (int i = year0 + 1; i < year1; i++){
        c.set(i, 11, 31);
        days += c.get(Calendar.DAY_OF_YEAR);
      }
      days += day1;
      if (negative) {
        return -days;
      } else {
        return days;
      }
    }
  }

  static int diffWeekOfYear(Calendar c0, Calendar c1){
    int days = diffDay(c0, c1);
    int w, firstDay;
    if (days < 0){
      w = c1.get(Calendar.DAY_OF_WEEK);
      firstDay = c0.getFirstDayOfWeek();
    } else {
      w = c0.get(Calendar.DAY_OF_WEEK);
      firstDay = c0.getFirstDayOfWeek();
    }
    return (days - (7 - (w - firstDay) % 7)) / 7 + 1;
  }

  protected Object exec(Object[] args, Context context){
    if (args.length != 2){
      undefined(args, context);
      return null;
    }
    Calendar c0 = date.getCalendar((Date)args[0], context);
    Calendar c1 = date.getCalendar((Date)args[1], context);

    switch (element){
    case Calendar.YEAR:
      return new Integer(diffYear(c0, c1));
    case Calendar.MONTH:
      return new Integer(diffMonth(c0, c1));
    case Calendar.WEEK_OF_YEAR:
      return new Integer(diffWeekOfYear(c0, c1));
    case Calendar.DAY_OF_YEAR:
      return new Integer(diffDay(c0, c1));
    case Calendar.HOUR_OF_DAY:
      return new Integer(diffHour(c0, c1));
    case Calendar.MINUTE:
      return new Integer(diffMinute(c0, c1));
    case Calendar.SECOND: {
      long l = diffSecond(c0, c1);
      if (l > Integer.MAX_VALUE || l < Integer.MIN_VALUE){
        return new Long(l);
      } else {
        return new Integer((int)l);
      }
    }
    case Calendar.MILLISECOND: {
      long l = diffMilliSecond(c0, c1);
      if (l > Integer.MAX_VALUE || l < Integer.MIN_VALUE){
        return new Long(l);
      } else {
        return new Integer((int)l);
      }
    }
    default:
      throw new IllegalArgumentException(String.valueOf(element));
    }
  }

  public String toString(){
    return "function " + name + "(Date, Date)";
  }
}