numberformat.java

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   *
   * @param locale The desired locale.
   *
   * @return An instance of the default <code>NumberFormat</code> class.
   */
  public static final NumberFormat getNumberInstance ()
  {
    return getNumberInstance (Locale.getDefault());
  }

  /**
   * This method returns a general purpose number formatting and parsing
   * class for the default locale.  This will be a concrete subclass of
   * <code>NumberFormat</code>, but the actual class returned is dependent
   * on the locale.
   *
   * @return An instance of a generic number formatter for the default locale.
   */
  public static NumberFormat getNumberInstance (Locale loc)
  {
    return computeInstance (loc, "numberFormat", "#,##0.###");
  }

  /**
   * This method returns an instance of <code>NumberFormat</code> suitable
   * for formatting and parsing percentage values in the default locale.
   *
   * @return An instance of <code>NumberFormat</code> for handling percentages.
   */
  public static final NumberFormat getPercentInstance ()
  {
    return getPercentInstance (Locale.getDefault());
  }

  /**
   * This method returns an instance of <code>NumberFormat</code> suitable
   * for formatting and parsing percentage values in the specified locale.
   *
   * @param locale The desired locale.
   *
   * @return An instance of <code>NumberFormat</code> for handling percentages.
   */
  public static NumberFormat getPercentInstance (Locale loc)
  {
    return computeInstance (loc, "percentFormat", "#,##0%");
  }

  /**
   * This method returns a hash value for this object.
   *
   * @return The hash code.
   */
  public int hashCode ()
  {
    int hash = super.hashCode();
    hash ^= (maximumFractionDigits + maximumIntegerDigits
	     + minimumFractionDigits + minimumIntegerDigits);
    if (groupingUsed)
      hash ^= 0xf0f0;
    if (parseIntegerOnly)
      hash ^= 0x0f0f;
    return hash;
  }

  /**
   * This method tests whether or not grouping is in use.  Grouping is
   * a method of marking separations in numbers, such as thousand separators
   * in the US English locale.  The grouping positions and symbols are all
   * locale specific.  As an example, with grouping disabled, the number one
   * million would appear as "1000000".  With grouping enabled, this number
   * might appear as "1,000,000".  (Both of these assume the US English
   * locale).
   *
   * @return <code>true</code> if grouping is enabled,
   * <code>false</code> otherwise. 
   */
  public boolean isGroupingUsed ()
  {
    return groupingUsed;
  }

  /**
   * This method tests whether or not only integer values should be parsed.
   * If this class is parsing only integers, parsing stops at the decimal
   * point.
   *
   * @return <code>true</code> if only integers are parsed,
   * <code>false</code> otherwise. 
   */
  public boolean isParseIntegerOnly ()
  {
    return parseIntegerOnly;
  }

  /**
   * This is a default constructor for use by subclasses.
   */
  public NumberFormat ()
  {
  }

  /**
   * This method parses the specified string into a <code>Number</code>.  This
   * will be a <code>Long</code> if possible, otherwise it will be a
   * <code>Double</code>.    If no number can be parsed, no exception is
   * thrown.  Instead, the parse position remains at its initial index.
   *
   * @param str The string to parse.
   * @param pp The desired <code>ParsePosition</code>.
   *
   * @return The parsed <code>Number</code>
   */
  public abstract Number parse (String sourceStr, ParsePosition pos);

  /**
   * This method parses the specified string into a <code>Number</code>.  This
   * will be a <code>Long</code> if possible, otherwise it will be a
   * <code>Double</code>.  If no number can be parsed, an exception will be
   * thrown.
   *
   * @param str The string to parse.
   *
   * @return The parsed <code>Number</code>
   *
   * @exception ParseException If no number can be parsed.
   */
  public Number parse (String sourceStr) throws ParseException
  {
    ParsePosition pp = new ParsePosition (0);
    Number r = parse (sourceStr, pp);
    if (r == null)
      {
	int index = pp.getErrorIndex();
	if (index < 0)
	  index = pp.getIndex();
	throw new ParseException ("couldn't parse number", index);
      }
    return r;
  }

  /**
   * This method parses the specified string into an <code>Object</code>.  This
   * will be a <code>Long</code> if possible, otherwise it will be a
   * <code>Double</code>.    If no number can be parsed, no exception is
   * thrown.  Instead, the parse position remains at its initial index.
   *
   * @param str The string to parse.
   * @param pp The desired <code>ParsePosition</code>.
  *
  * @return The parsed <code>Object</code>
  */
  public final Object parseObject (String sourceStr, ParsePosition pos)
  {
    return parse (sourceStr, pos);
  }

  /**
   * This method sets the grouping behavior of this formatter.  Grouping is
   * a method of marking separations in numbers, such as thousand separators
   * in the US English locale.  The grouping positions and symbols are all
   * locale specific.  As an example, with grouping disabled, the number one
   * million would appear as "1000000".  With grouping enabled, this number
   * might appear as "1,000,000".  (Both of these assume the US English
   * locale).
   *
   * @param groupingUsed <code>true</code> to enable grouping,
   *                     <code>false</code> to disable it. 
   */
  public void setGroupingUsed (boolean newValue)
  {
    groupingUsed = newValue;
  }

  /**
   * This method sets the maximum number of digits allowed in the fraction
   * portion of a number to the specified value.  If this is less than the
   * current minimum allowed digits, the minimum allowed digits value will
   * be lowered to be equal to the new maximum allowed digits value.
   *
   * @param maximumFractionDigits The new maximum fraction digits value.
   */
  public void setMaximumFractionDigits (int newValue)
  {
    maximumFractionDigits = newValue;
    if (getMinimumFractionDigits () > maximumFractionDigits)
      setMinimumFractionDigits (maximumFractionDigits);
  }

  /**
   * This method sets the maximum number of digits allowed in the integer
   * portion of a number to the specified value.  If this is less than the
   * current minimum allowed digits, the minimum allowed digits value will
   * be lowered to be equal to the new maximum allowed digits value.
   *
   * @param maximumIntegerDigits The new maximum integer digits value.
   */
  public void setMaximumIntegerDigits (int newValue)
  {
    maximumIntegerDigits = newValue;
    if (getMinimumIntegerDigits () > maximumIntegerDigits)
      setMinimumIntegerDigits (maximumIntegerDigits);
  }

  /**
   * This method sets the minimum number of digits allowed in the fraction
   * portion of a number to the specified value.  If this is greater than the
   * current maximum allowed digits, the maximum allowed digits value will
   * be raised to be equal to the new minimum allowed digits value.
   *
   * @param minimumFractionDigits The new minimum fraction digits value.
   */
  public void setMinimumFractionDigits (int newValue)
  {
    minimumFractionDigits = newValue;
    if (getMaximumFractionDigits () < minimumFractionDigits)
      setMaximumFractionDigits (minimumFractionDigits);
  }

  /**
   * This method sets the minimum number of digits allowed in the integer
   * portion of a number to the specified value.  If this is greater than the
   * current maximum allowed digits, the maximum allowed digits value will
   * be raised to be equal to the new minimum allowed digits value.
   *
   * @param minimumIntegerDigits The new minimum integer digits value.
   */
  public void setMinimumIntegerDigits (int newValue)
  {
    minimumIntegerDigits = newValue;
    if (getMaximumIntegerDigits () < minimumIntegerDigits)
      setMaximumIntegerDigits (minimumIntegerDigits);
  }

  /** 
   * This method sets the parsing behavior of this object to parse only 
   * integers or not.
   *
   * @param parseIntegerOnly <code>true</code> to parse only integers,
   *                         <code>false</code> otherwise. 
   */
  public void setParseIntegerOnly (boolean value)
  {
    parseIntegerOnly = value;
  }

  /**
   * This method is a specialization of the format method that performs
   * a simple formatting of the specified <code>double</code> number.
   *
   * @param number The <code>double</code> to format.
   *
   * @return The formatted number
   */
  public final String format (double number)
  {
    StringBuffer sbuf = new StringBuffer(50);
    format (number, sbuf, null);
    return sbuf.toString();
  }

  // These field names are fixed by the serialization spec.
  boolean groupingUsed;
  int maximumFractionDigits;
  private byte maxFractionDigits;
  int maximumIntegerDigits;
  private byte maxIntegerDigits;
  int minimumFractionDigits;
  private byte minFractionDigits;
  int minimumIntegerDigits;
  private byte minIntegerDigits;
  boolean parseIntegerOnly;
  private int serialVersionOnStream;
  private static final long serialVersionUID = -2308460125733713944L;

  private void readObject(ObjectInputStream stream)
    throws IOException, ClassNotFoundException
  {
    stream.defaultReadObject();
    if (serialVersionOnStream < 1)
      {
        maximumFractionDigits = maxFractionDigits;
	maximumIntegerDigits = maxIntegerDigits;
	minimumFractionDigits = minFractionDigits;
	minimumIntegerDigits = minIntegerDigits;
	serialVersionOnStream = 1;
      }
  }

  private void writeObject(ObjectOutputStream stream) throws IOException
  {
    maxFractionDigits = maximumFractionDigits < Byte.MAX_VALUE ?
      (byte) maximumFractionDigits : Byte.MAX_VALUE;
    maxIntegerDigits = maximumIntegerDigits < Byte.MAX_VALUE ?
      (byte) maximumIntegerDigits : Byte.MAX_VALUE;
    minFractionDigits = minimumFractionDigits < Byte.MAX_VALUE ?
      (byte) minimumFractionDigits : Byte.MAX_VALUE;
    minIntegerDigits = minimumIntegerDigits < Byte.MAX_VALUE ?
      (byte) minimumIntegerDigits : Byte.MAX_VALUE;
    serialVersionOnStream = 1;
    stream.defaultWriteObject();
  }
}