numberconverter.java

APACHE 公司出的java bean 工具包

     * <i>Converter</i>.
     * <p>
     * This method handles conversion to the following types:
     * <ul>
     *     <li><code>java.lang.Byte</code></li>
     *     <li><code>java.lang.Short</code></li>
     *     <li><code>java.lang.Integer</code></li>
     *     <li><code>java.lang.Long</code></li>
     *     <li><code>java.lang.Float</code></li>
     *     <li><code>java.lang.Double</code></li>
     *     <li><code>java.math.BigDecimal</code></li>
     *     <li><code>java.math.BigInteger</code></li>
     * </ul>
     * @param sourceType The type being converted from
     * @param targetType The Number type to convert to
     * @param value The Number to convert.
     *
     * @return The converted value.
     */
    private Number toNumber(Class sourceType, Class targetType, Number value) {

        // Correct Number type already
        if (targetType.equals(value.getClass())) {
            return value;
        }

        // Byte
        if (targetType.equals(Byte.class)) {
            long longValue = value.longValue();
            if (longValue > Byte.MAX_VALUE) {
                throw new ConversionException(toString(sourceType) + " value '" + value
                        + "' is too large for " + toString(targetType));
            }
            if (longValue < Byte.MIN_VALUE) {
                throw new ConversionException(toString(sourceType) + " value '" + value
                        + "' is too small " + toString(targetType));
            }
            return new Byte(value.byteValue());
        }

        // Short
        if (targetType.equals(Short.class)) {
            long longValue = value.longValue();
            if (longValue > Short.MAX_VALUE) {
                throw new ConversionException(toString(sourceType) + " value '" + value
                        + "' is too large for " + toString(targetType));
            }
            if (longValue < Short.MIN_VALUE) {
                throw new ConversionException(toString(sourceType) + " value '" + value
                        + "' is too small " + toString(targetType));
            }
            return new Short(value.shortValue());
        }

        // Integer
        if (targetType.equals(Integer.class)) {
            long longValue = value.longValue();
            if (longValue > Integer.MAX_VALUE) {
                throw new ConversionException(toString(sourceType) + " value '" + value
                        + "' is too large for " + toString(targetType));
            }
            if (longValue < Integer.MIN_VALUE) {
                throw new ConversionException(toString(sourceType) + " value '" + value
                        + "' is too small " + toString(targetType));
            }
            return new Integer(value.intValue());
        }

        // Long
        if (targetType.equals(Long.class)) {
            return new Long(value.longValue());
        }

        // Float
        if (targetType.equals(Float.class)) {
            if (value.doubleValue() > Float.MAX_VALUE) {
                throw new ConversionException(toString(sourceType) + " value '" + value
                        + "' is too large for " + toString(targetType));
            }
            return new Float(value.floatValue());
        }

        // Double
        if (targetType.equals(Double.class)) {
            return new Double(value.doubleValue());
        }

        // BigDecimal
        if (targetType.equals(BigDecimal.class)) {
            if (value instanceof Float || value instanceof Double) {
                return new BigDecimal(value.toString());
            } else if (value instanceof BigInteger) {
                return new BigDecimal((BigInteger)value);
            } else {
                return BigDecimal.valueOf(value.longValue());
            }
        }

        // BigInteger
        if (targetType.equals(BigInteger.class)) {
            if (value instanceof BigDecimal) {
                return ((BigDecimal)value).toBigInteger();
            } else {
                return BigInteger.valueOf(value.longValue());
            }
        }

        String msg = toString(getClass()) + " cannot handle conversion to '"
                   + toString(targetType) + "'";
        if (log().isWarnEnabled()) {
            log().warn("    " + msg);
        }
        throw new ConversionException(msg);

    }

    /**
     * Default String to Number conversion.
     * <p>
     * This method handles conversion from a String to the following types:
     * <ul>
     *     <li><code>java.lang.Byte</code></li>
     *     <li><code>java.lang.Short</code></li>
     *     <li><code>java.lang.Integer</code></li>
     *     <li><code>java.lang.Long</code></li>
     *     <li><code>java.lang.Float</code></li>
     *     <li><code>java.lang.Double</code></li>
     *     <li><code>java.math.BigDecimal</code></li>
     *     <li><code>java.math.BigInteger</code></li>
     * </ul>
     * @param sourceType The type being converted from
     * @param targetType The Number type to convert to
     * @param value The String value to convert.
     *
     * @return The converted Number value.
     */
    private Number toNumber(Class sourceType, Class targetType, String value) {

        // Byte
        if (targetType.equals(Byte.class)) {
            return new Byte(value);
        }

        // Short
        if (targetType.equals(Short.class)) {
            return new Short(value);
        }

        // Integer
        if (targetType.equals(Integer.class)) {
            return new Integer(value);
        }

        // Long
        if (targetType.equals(Long.class)) {
            return new Long(value);
        }

        // Float
        if (targetType.equals(Float.class)) {
            return new Float(value);
        }

        // Double
        if (targetType.equals(Double.class)) {
            return new Double(value);
        }

        // BigDecimal
        if (targetType.equals(BigDecimal.class)) {
            return new BigDecimal(value);
        }

        // BigInteger
        if (targetType.equals(BigInteger.class)) {
            return new BigInteger(value);
        }

        String msg = toString(getClass()) + " cannot handle conversion from '" +
                     toString(sourceType) + "' to '" + toString(targetType) + "'";
        if (log().isWarnEnabled()) {
            log().warn("    " + msg);
        }
        throw new ConversionException(msg);
    }

    /**
     * Provide a String representation of this number converter.
     *
     * @return A String representation of this number converter
     */
    public String toString() {
        StringBuffer buffer = new StringBuffer();
        buffer.append(toString(getClass()));
        buffer.append("[UseDefault=");
        buffer.append(isUseDefault());
        buffer.append(", UseLocaleFormat=");
        buffer.append(useLocaleFormat);
        if (pattern != null) {
            buffer.append(", Pattern=");
            buffer.append(pattern);
        }
        if (locale != null) {
            buffer.append(", Locale=");
            buffer.append(locale);
        }
        buffer.append(']');
        return buffer.toString();
    }

    /**
     * Return a NumberFormat to use for Conversion.
     *
     * @return The NumberFormat.
     */
    private NumberFormat getFormat() {
        NumberFormat format = null;
        if (pattern != null) {
            if (locale == null) {
                if (log().isDebugEnabled()) {
                    log().debug("    Using pattern '" + pattern + "'");
                }
                format = new DecimalFormat(pattern);
            } else {
                if (log().isDebugEnabled()) {
                    log().debug("    Using pattern '" + pattern + "'" +
                              " with Locale[" + locale + "]");
                }
                DecimalFormatSymbols symbols = new DecimalFormatSymbols(locale);
                format = new DecimalFormat(pattern, symbols);
            }
        } else {
            if (locale == null) {
                if (log().isDebugEnabled()) {
                    log().debug("    Using default Locale format");
                }
                format = NumberFormat.getInstance();
            } else {
                if (log().isDebugEnabled()) {
                    log().debug("    Using Locale[" + locale + "] format");
                }
                format = NumberFormat.getInstance(locale);
            }
        }
        if (!allowDecimals) {
            format.setParseIntegerOnly(true);
        }
        return format;
    }

    /**
     * Convert a String into a <code>Number</code> object.
     * @param sourceType TODO
     * @param targetType The type to convert the value to
     * @param value The String date value.
     * @param format The NumberFormat to parse the String value.
     *
     * @return The converted Number object.
     * @throws ConversionException if the String cannot be converted.
     */
    private Number parse(Class sourceType, Class targetType, String value, NumberFormat format) {
        ParsePosition pos = new ParsePosition(0);
        Number parsedNumber = (Number)format.parse(value, pos);
        if (pos.getErrorIndex() >= 0 || pos.getIndex() != value.length() || parsedNumber == null) {
            String msg = "Error converting from '" + toString(sourceType) + "' to '" + toString(targetType) + "'";
            if (format instanceof DecimalFormat) {
                msg += " using pattern '" + ((DecimalFormat)format).toPattern() + "'";
            }
            if (locale != null) {
                msg += " for locale=[" + locale + "]";
            }
            if (log().isDebugEnabled()) {
                log().debug("    " + msg);
            }
            throw new ConversionException(msg);
        }
        return parsedNumber;
    }

}