numberformat.java

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     * The default format is one of the styles provided by the other
     * factory methods: getNumberInstance, getIntegerInstance,
     * getCurrencyInstance or getPercentInstance.
     * Exactly which one is locale dependant.
     */
    public final static NumberFormat getInstance() {
        return getInstance(Locale.getDefault(), NUMBERSTYLE);
    }

    /**
     * Returns the default number format for the specified locale.
     * The default format is one of the styles provided by the other
     * factory methods: getNumberInstance, getIntegerInstance,
     * getCurrencyInstance or getPercentInstance.
     * Exactly which one is locale dependant.
     */
    public static NumberFormat getInstance(Locale inLocale) {
        return getInstance(inLocale, NUMBERSTYLE);
    }

    /**
     * Returns a general-purpose number format for the current default locale.
     */
    public final static NumberFormat getNumberInstance() {
        return getInstance(Locale.getDefault(), NUMBERSTYLE);
    }

    /**
     * Returns a general-purpose number format for the specified locale.
     */
    public static NumberFormat getNumberInstance(Locale inLocale) {
        return getInstance(inLocale, NUMBERSTYLE);
    }

    /**
     * Returns an integer number format for the current default locale. The
     * returned number format is configured to round floating point numbers
     * to the nearest integer using IEEE half-even rounding (see {@link 
     * java.math.BigDecimal#ROUND_HALF_EVEN ROUND_HALF_EVEN}) for formatting,
     * and to parse only the integer part of an input string (see {@link
     * #isParseIntegerOnly isParseIntegerOnly}).
     *
     * @return a number format for integer values
     * @since 1.4
     */
    public final static NumberFormat getIntegerInstance() {
        return getInstance(Locale.getDefault(), INTEGERSTYLE);
    }

    /**
     * Returns an integer number format for the specified locale. The
     * returned number format is configured to round floating point numbers
     * to the nearest integer using IEEE half-even rounding (see {@link 
     * java.math.BigDecimal#ROUND_HALF_EVEN ROUND_HALF_EVEN}) for formatting,
     * and to parse only the integer part of an input string (see {@link
     * #isParseIntegerOnly isParseIntegerOnly}).
     *
     * @param inLocale the locale for which a number format is needed
     * @return a number format for integer values
     * @since 1.4
     */
    public static NumberFormat getIntegerInstance(Locale inLocale) {
        return getInstance(inLocale, INTEGERSTYLE);
    }

    /**
     * Returns a currency format for the current default locale.
     */
    public final static NumberFormat getCurrencyInstance() {
        return getInstance(Locale.getDefault(), CURRENCYSTYLE);
    }

    /**
     * Returns a currency format for the specified locale.
     */
    public static NumberFormat getCurrencyInstance(Locale inLocale) {
        return getInstance(inLocale, CURRENCYSTYLE);
    }

    /**
     * Returns a percentage format for the current default locale.
     */
    public final static NumberFormat getPercentInstance() {
        return getInstance(Locale.getDefault(), PERCENTSTYLE);
    }

    /**
     * Returns a percentage format for the specified locale.
     */
    public static NumberFormat getPercentInstance(Locale inLocale) {
        return getInstance(inLocale, PERCENTSTYLE);
    }

    /**
     * Returns a scientific format for the current default locale.
     */
    /*public*/ final static NumberFormat getScientificInstance() {
        return getInstance(Locale.getDefault(), SCIENTIFICSTYLE);
    }

    /**
     * Returns a scientific format for the specified locale.
     */
    /*public*/ static NumberFormat getScientificInstance(Locale inLocale) {
        return getInstance(inLocale, SCIENTIFICSTYLE);
    }


    /**
     * Get the set of Locales for which NumberFormats are installed
     * @return available locales
     */
    public static Locale[] getAvailableLocales() {
        return LocaleData.getAvailableLocales("NumberPatterns");
    }

    /**
     * Overrides hashCode
     */
    public int hashCode() {
        return maximumIntegerDigits * 37 + maxFractionDigits;
        // just enough fields for a reasonable distribution
    }

    /**
     * Overrides equals
     */
    public boolean equals(Object obj) {
        if (obj == null) return false;
        if (this == obj)
            return true;
        if (getClass() != obj.getClass())
            return false;
        NumberFormat other = (NumberFormat) obj;
        return (maximumIntegerDigits == other.maximumIntegerDigits
            && minimumIntegerDigits == other.minimumIntegerDigits
            && maximumFractionDigits == other.maximumFractionDigits
            && minimumFractionDigits == other.minimumFractionDigits
            && groupingUsed == other.groupingUsed
            && parseIntegerOnly == other.parseIntegerOnly);
    }

    /**
     * Overrides Cloneable
     */
    public Object clone()
    {
        NumberFormat other = (NumberFormat) super.clone();
        return other;
    }

    /**
     * Returns true if grouping is used in this format. For example, in the
     * English locale, with grouping on, the number 1234567 might be formatted
     * as "1,234,567". The grouping separator as well as the size of each group
     * is locale dependant and is determined by sub-classes of NumberFormat.
     * @see #setGroupingUsed
     */
    public boolean isGroupingUsed() {
        return groupingUsed;
    }

    /**
     * Set whether or not grouping will be used in this format.
     * @see #isGroupingUsed
     */
    public void setGroupingUsed(boolean newValue) {
        groupingUsed = newValue;
    }

    /**
     * Returns the maximum number of digits allowed in the integer portion of a
     * number.
     * @see #setMaximumIntegerDigits
     */
    public int getMaximumIntegerDigits() {
        return maximumIntegerDigits;
    }

    /**
     * Sets the maximum number of digits allowed in the integer portion of a
     * number. maximumIntegerDigits must be >= minimumIntegerDigits.  If the
     * new value for maximumIntegerDigits is less than the current value
     * of minimumIntegerDigits, then minimumIntegerDigits will also be set to
     * the new value.
     * @param newValue the maximum number of integer digits to be shown; if
     * less than zero, then zero is used. The concrete subclass may enforce an
     * upper limit to this value appropriate to the numeric type being formatted.
     * @see #getMaximumIntegerDigits
     */
    public void setMaximumIntegerDigits(int newValue) {
        maximumIntegerDigits = Math.max(0,newValue);
        if (minimumIntegerDigits > maximumIntegerDigits)
            minimumIntegerDigits = maximumIntegerDigits;
    }

    /**
     * Returns the minimum number of digits allowed in the integer portion of a
     * number.
     * @see #setMinimumIntegerDigits
     */
    public int getMinimumIntegerDigits() {
        return minimumIntegerDigits;
    }

    /**
     * Sets the minimum number of digits allowed in the integer portion of a
     * number. minimumIntegerDigits must be <= maximumIntegerDigits.  If the
     * new value for minimumIntegerDigits exceeds the current value
     * of maximumIntegerDigits, then maximumIntegerDigits will also be set to
     * the new value
     * @param newValue the minimum number of integer digits to be shown; if
     * less than zero, then zero is used. The concrete subclass may enforce an
     * upper limit to this value appropriate to the numeric type being formatted.
     * @see #getMinimumIntegerDigits
     */
    public void setMinimumIntegerDigits(int newValue) {
        minimumIntegerDigits = Math.max(0,newValue);
        if (minimumIntegerDigits > maximumIntegerDigits)
            maximumIntegerDigits = minimumIntegerDigits;
    }

    /**
     * Returns the maximum number of digits allowed in the fraction portion of a
     * number.
     * @see #setMaximumFractionDigits
     */
    public int getMaximumFractionDigits() {
        return maximumFractionDigits;
    }

    /**
     * Sets the maximum number of digits allowed in the fraction portion of a
     * number. maximumFractionDigits must be >= minimumFractionDigits.  If the
     * new value for maximumFractionDigits is less than the current value
     * of minimumFractionDigits, then minimumFractionDigits will also be set to
     * the new value.
     * @param newValue the maximum number of fraction digits to be shown; if
     * less than zero, then zero is used. The concrete subclass may enforce an
     * upper limit to this value appropriate to the numeric type being formatted.
     * @see #getMaximumFractionDigits
     */
    public void setMaximumFractionDigits(int newValue) {
        maximumFractionDigits = Math.max(0,newValue);
        if (maximumFractionDigits < minimumFractionDigits)
            minimumFractionDigits = maximumFractionDigits;
    }

    /**
     * Returns the minimum number of digits allowed in the fraction portion of a
     * number.
     * @see #setMinimumFractionDigits
     */
    public int getMinimumFractionDigits() {
        return minimumFractionDigits;
    }

    /**
     * Sets the minimum number of digits allowed in the fraction portion of a
     * number. minimumFractionDigits must be <= maximumFractionDigits.  If the
     * new value for minimumFractionDigits exceeds the current value
     * of maximumFractionDigits, then maximumIntegerDigits will also be set to
     * the new value
     * @param newValue the minimum number of fraction digits to be shown; if
     * less than zero, then zero is used. The concrete subclass may enforce an
     * upper limit to this value appropriate to the numeric type being formatted.
     * @see #getMinimumFractionDigits
     */
    public void setMinimumFractionDigits(int newValue) {
        minimumFractionDigits = Math.max(0,newValue);
        if (maximumFractionDigits < minimumFractionDigits)
            maximumFractionDigits = minimumFractionDigits;
    }
    
    /**
     * Gets the currency used by this number format when formatting
     * currency values. The initial value is derived in a locale dependent
     * way. The returned value may be null if no valid
     * currency could be determined and no currency has been set using
     * {@link #setCurrency(java.util.Currency) setCurrency}.
     * <p>
     * The default implementation throws
     * <code>UnsupportedOperationException</code>.
     *
     * @return the currency used by this number format, or <code>null</code>
     * @exception UnsupportedOperationException if the number format class
     * doesn't implement currency formatting
     * @since 1.4
     */
    public Currency getCurrency() {
        throw new UnsupportedOperationException();
    }
    
    /**
     * Sets the currency used by this number format when formatting
     * currency values. This does not update the minimum or maximum
     * number of fraction digits used by the number format.
     * <p>
     * The default implementation throws
     * <code>UnsupportedOperationException</code>.
     *
     * @param currency the new currency to be used by this number format
     * @exception UnsupportedOperationException if the number format class
     * doesn't implement currency formatting
     * @exception NullPointerException if <code>currency</code> is null
     * @since 1.4
     */
    public void setCurrency(Currency currency) {
        throw new UnsupportedOperationException();
    }

    // =======================privates===============================

    private static NumberFormat getInstance(Locale desiredLocale,
                                           int choice) {
        /* try the cache first */
        String[] numberPatterns = (String[])cachedLocaleData.get(desiredLocale);
        if (numberPatterns == null) { /* cache miss */
            ResourceBundle resource = LocaleData.getLocaleElements(desiredLocale);
            numberPatterns = resource.getStringArray("NumberPatterns");
            /* update cache */
            cachedLocaleData.put(desiredLocale, numberPatterns);
        }
        
        DecimalFormatSymbols symbols = new DecimalFormatSymbols(desiredLocale);
        int entry = (choice == INTEGERSTYLE) ? NUMBERSTYLE : choice;
        DecimalFormat format = new DecimalFormat(numberPatterns[entry], symbols);
        
        if (choice == INTEGERSTYLE) {
            format.setMaximumFractionDigits(0);
            format.setDecimalSeparatorAlwaysShown(false);
            format.setParseIntegerOnly(true);
        } else if (choice == CURRENCYSTYLE) {
            format.adjustForCurrencyDefaultFractionDigits();
        }

        return format;
    }

    /**
     * First, read in the default serializable data.
     *
     * Then, if <code>serialVersionOnStream</code> is less than 1, indicating that