calendar.java

gcc的组建

   *         the valid range.  The value of field must be >= 0 and
   *         <= <code>FIELD_COUNT</code>.
   */
  public final void clear(int field)
  {
    int[] tempFields = 
                       {
                         1, 1970, JANUARY, 1, 1, 1, 1, THURSDAY, 1, AM, 0, 0, 0,
                         0, 0, zone.getRawOffset(), 0
                       };
    isTimeSet = false;
    areFieldsSet = false;
    isSet[field] = false;
    fields[field] = tempFields[field];
  }

  /**
   * Determines if the specified field has a valid value.
   * @return true if the specified field has a value.
   * @throws ArrayIndexOutOfBoundsException if the field is outside
   *         the valid range.  The value of field must be >= 0 and
   *         <= <code>FIELD_COUNT</code>.
   */
  public final boolean isSet(int field)
  {
    return isSet[field];
  }

  /**
   * Fills any unset fields in the time field list
   */
  protected void complete()
  {
    if (! isTimeSet)
      computeTime();
    if (! areFieldsSet)
      computeFields();
  }

  /**
   * Compares the given calendar with this.
   * @param o the object to that we should compare.
   * @return true, if the given object is a calendar, that represents
   * the same time (but doesn't necessary have the same fields).
   */
  public boolean equals(Object o)
  {
    if (! (o instanceof Calendar))
      return false;
    Calendar cal = (Calendar) o;
    if (getTimeInMillis() == ((Calendar) o).getTimeInMillis()
        && cal.getFirstDayOfWeek() == getFirstDayOfWeek()
        && cal.isLenient() == isLenient()
        && cal.getMinimalDaysInFirstWeek() == getMinimalDaysInFirstWeek())
      {
        TimeZone self = getTimeZone();
        TimeZone oth = cal.getTimeZone();
        return self == null ? oth == null : self.equals(oth);
      }
    return false;
  }

  /**
   * Returns a hash code for this calendar.
   * @return a hash code, which fullfits the general contract of
   * <code>hashCode()</code>
   */
  public int hashCode()
  {
    long time = getTimeInMillis();
    int val = (int) ((time & 0xffffffffL) ^ (time >> 32));
    val += (getFirstDayOfWeek() + (isLenient() ? 1230 : 1237)
            + getMinimalDaysInFirstWeek());
    TimeZone self = getTimeZone();
    if (self != null)
      val ^= self.hashCode();
    return val;
  }

  /**
   * Compares the given calendar with this.
   * @param o the object to that we should compare.
   * @return true, if the given object is a calendar, and this calendar
   * represents a smaller time than the calendar o.
   * @exception ClassCastException if o is not an calendar.
   * @since JDK1.2 you don't need to override this method
   */
  public boolean before(Object o)
  {
    return getTimeInMillis() < ((Calendar) o).getTimeInMillis();
  }

  /**
   * Compares the given calendar with this.
   * @param o the object to that we should compare.
   * @return true, if the given object is a calendar, and this calendar
   * represents a bigger time than the calendar o.
   * @exception ClassCastException if o is not an calendar.
   * @since JDK1.2 you don't need to override this method
   */
  public boolean after(Object o)
  {
    return getTimeInMillis() > ((Calendar) o).getTimeInMillis();
  }

  /**
   * Adds the specified amount of time to the given time field.  The
   * amount may be negative to subtract the time.  If the field overflows
   * it does what you expect: Jan, 25 + 10 Days is Feb, 4.
   * @param field the time field. One of the time field constants.
   * @param amount the amount of time.
   * @throws ArrayIndexOutOfBoundsException if the field is outside
   *         the valid range.  The value of field must be >= 0 and
   *         <= <code>FIELD_COUNT</code>.
   */
  public abstract void add(int field, int amount);

  /**
   * Rolls the specified time field up or down.  This means add one
   * to the specified field, but don't change the other fields.  If
   * the maximum for this field is reached, start over with the
   * minimum value.  <br>
   *
   * <strong>Note:</strong> There may be situation, where the other
   * fields must be changed, e.g rolling the month on May, 31.
   * The date June, 31 is automatically converted to July, 1.
   * @param field the time field. One of the time field constants.
   * @param up the direction, true for up, false for down.
   * @throws ArrayIndexOutOfBoundsException if the field is outside
   *         the valid range.  The value of field must be >= 0 and
   *         <= <code>FIELD_COUNT</code>.
   */
  public abstract void roll(int field, boolean up);

  /**
   * Rolls up or down the specified time field by the given amount.
   * A negative amount rolls down.  The default implementation is
   * call <code>roll(int, boolean)</code> for the specified amount.
   *
   * Subclasses should override this method to do more intuitiv things.
   *
   * @param field the time field. One of the time field constants.
   * @param amount the amount to roll by, positive for rolling up,
   * negative for rolling down.
   * @throws ArrayIndexOutOfBoundsException if the field is outside
   *         the valid range.  The value of field must be >= 0 and
   *         <= <code>FIELD_COUNT</code>.
   * @since JDK1.2
   */
  public void roll(int field, int amount)
  {
    while (amount > 0)
      {
	roll(field, true);
	amount--;
      }
    while (amount < 0)
      {
	roll(field, false);
	amount++;
      }
  }

  /**
   * Sets the time zone to the specified value.
   * @param zone the new time zone
   */
  public void setTimeZone(TimeZone zone)
  {
    this.zone = zone;
  }

  /**
   * Gets the time zone of this calendar
   * @return the current time zone.
   */
  public TimeZone getTimeZone()
  {
    return zone;
  }

  /**
   * Specifies if the date/time interpretation should be lenient.
   * If the flag is set, a date such as "February 30, 1996" will be
   * treated as the 29th day after the February 1.  If this flag
   * is false, such dates will cause an exception.
   * @param lenient true, if the date should be interpreted linient,
   * false if it should be interpreted strict.
   */
  public void setLenient(boolean lenient)
  {
    this.lenient = lenient;
  }

  /**
   * Tells if the date/time interpretation is lenient.
   * @return true, if the date should be interpreted linient,
   * false if it should be interpreted strict.
   */
  public boolean isLenient()
  {
    return lenient;
  }

  /**
   * Sets what the first day of week is.  This is used for
   * WEEK_OF_MONTH and WEEK_OF_YEAR fields.
   * @param value the first day of week.  One of SUNDAY to SATURDAY.
   */
  public void setFirstDayOfWeek(int value)
  {
    firstDayOfWeek = value;
  }

  /**
   * Gets what the first day of week is.  This is used for
   * WEEK_OF_MONTH and WEEK_OF_YEAR fields.
   * @return the first day of week.  One of SUNDAY to SATURDAY.
   */
  public int getFirstDayOfWeek()
  {
    return firstDayOfWeek;
  }

  /**
   * Sets how many days are required in the first week of the year.
   * If the first day of the year should be the first week you should
   * set this value to 1.  If the first week must be a full week, set
   * it to 7.
   * @param value the minimal days required in the first week.
   */
  public void setMinimalDaysInFirstWeek(int value)
  {
    minimalDaysInFirstWeek = value;
  }

  /**
   * Gets how many days are required in the first week of the year.
   * @return the minimal days required in the first week.
   * @see #setMinimalDaysInFirstWeek
   */
  public int getMinimalDaysInFirstWeek()
  {
    return minimalDaysInFirstWeek;
  }

  /**
   * Gets the smallest value that is allowed for the specified field.
   * @param field the time field. One of the time field constants.
   * @return the smallest value.
   */
  public abstract int getMinimum(int field);

  /**
   * Gets the biggest value that is allowed for the specified field.
   * @param field the time field. One of the time field constants.
   * @return the biggest value.
   */
  public abstract int getMaximum(int field);

  /**
   * Gets the greatest minimum value that is allowed for the specified field.
   * @param field the time field. One of the time field constants.
   * @return the greatest minimum value.
   */
  public abstract int getGreatestMinimum(int field);

  /**
   * Gets the smallest maximum value that is allowed for the
   * specified field.  For example this is 28 for DAY_OF_MONTH.
   * @param field the time field. One of the time field constants.
   * @return the least maximum value.
   */
  public abstract int getLeastMaximum(int field);

  /**
   * Gets the actual minimum value that is allowed for the specified field.
   * This value is dependent on the values of the other fields.
   * @param field the time field. One of the time field constants.
   * @return the actual minimum value.
   * @throws ArrayIndexOutOfBoundsException if the field is outside
   *         the valid range.  The value of field must be >= 0 and
   *         <= <code>FIELD_COUNT</code>.
   * @since jdk1.2
   */
  public int getActualMinimum(int field)
  {
    Calendar tmp = (Calendar) clone(); // To avoid restoring state
    int min = tmp.getGreatestMinimum(field);
    int end = tmp.getMinimum(field);
    tmp.set(field, min);
    for (; min > end; min--)
      {
	tmp.add(field, -1); // Try to get smaller
	if (tmp.get(field) != min - 1)
	  break; // Done if not successful
      }
    return min;
  }

  /**
   * Gets the actual maximum value that is allowed for the specified field.
   * This value is dependent on the values of the other fields.
   * @param field the time field. One of the time field constants.
   * @return the actual maximum value.
   * @throws ArrayIndexOutOfBoundsException if the field is outside
   *         the valid range.  The value of field must be >= 0 and
   *         <= <code>FIELD_COUNT</code>.
   * @since jdk1.2
   */
  public int getActualMaximum(int field)
  {
    Calendar tmp = (Calendar) clone(); // To avoid restoring state
    int max = tmp.getLeastMaximum(field);
    int end = tmp.getMaximum(field);
    tmp.set(field, max);
    for (; max < end; max++)
      {
	tmp.add(field, 1);
	if (tmp.get(field) != max + 1)
	  break;
      }
    return max;
  }

  /**
   * Return a clone of this object.
   */
  public Object clone()
  {
    try
      {
	Calendar cal = (Calendar) super.clone();
	cal.fields = (int[]) fields.clone();
	cal.isSet = (boolean[]) isSet.clone();
	return cal;
      }
    catch (CloneNotSupportedException ex)
      {
	return null;
      }
  }

  private static final String[] fieldNames = 
                                             {
                                               ",ERA=", ",YEAR=", ",MONTH=",
                                               ",WEEK_OF_YEAR=",
                                               ",WEEK_OF_MONTH=",
                                               ",DAY_OF_MONTH=",
                                               ",DAY_OF_YEAR=", ",DAY_OF_WEEK=",
                                               ",DAY_OF_WEEK_IN_MONTH=",
                                               ",AM_PM=", ",HOUR=",
                                               ",HOUR_OF_DAY=", ",MINUTE=",
                                               ",SECOND=", ",MILLISECOND=",
                                               ",ZONE_OFFSET=", ",DST_OFFSET="
                                             };

  /**
   * Returns a string representation of this object.  It is mainly
   * for debugging purposes and its content is implementation
   * specific.
   */
  public String toString()
  {
    StringBuffer sb = new StringBuffer();
    sb.append(getClass().getName()).append('[');
    sb.append("time=");
    if (isTimeSet)
      sb.append(time);
    else
      sb.append("?");
    sb.append(",zone=" + zone);
    sb.append(",areFieldsSet=" + areFieldsSet);
    for (int i = 0; i < FIELD_COUNT; i++)
      {
	sb.append(fieldNames[i]);
	if (isSet[i])
	  sb.append(fields[i]);
	else
	  sb.append("?");
      }
    sb.append(",lenient=").append(lenient);
    sb.append(",firstDayOfWeek=").append(firstDayOfWeek);
    sb.append(",minimalDaysInFirstWeek=").append(minimalDaysInFirstWeek);
    sb.append("]");
    return sb.toString();
  }

  /**
   * Saves the state of the object to the stream.  Ideally we would
   * only write the time field, but we need to be compatible with
   * earlier versions. <br>
   *
   * This doesn't write the JDK1.1 field nextStamp to the stream, as
   * I don't know what it is good for, and because the documentation
   * says, that it could be omitted.  */
  private void writeObject(ObjectOutputStream stream) throws IOException
  {
    if (! isTimeSet)
      computeTime();
    stream.defaultWriteObject();
  }

  /**
   * Reads the object back from stream (deserialization).
   */
  private void readObject(ObjectInputStream stream)
    throws IOException, ClassNotFoundException
  {
    stream.defaultReadObject();
    if (! isTimeSet)
      computeTime();

    if (serialVersionOnStream > 1)
      {
	// This is my interpretation of the serial number:
	// Sun wants to remove all fields from the stream someday
	// and will then increase the serialVersion number again.
	// We prepare to be compatible.
	fields = new int[FIELD_COUNT];
	isSet = new boolean[FIELD_COUNT];
	areFieldsSet = false;
      }
  }
}