/*
* Copyright 2002-2009 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package xgenerator.util;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.text.ParseException;
/**
* Miscellaneous utility methods for number conversion and parsing.
* Mainly for internal use within the framework; consider Jakarta's
* Commons Lang for a more comprehensive suite of string utilities.
*
* @author Juergen Hoeller
* @author Rob Harrop
* @since 1.1.2
*/
public abstract class NumberUtils {
/**
* Convert the given number into an instance of the given target class.
* @param number the number to convert
* @param targetClass the target class to convert to
* @return the converted number
* @throws IllegalArgumentException if the target class is not supported
* (i.e. not a standard Number subclass as included in the JDK)
* @see java.lang.Byte
* @see java.lang.Short
* @see java.lang.Integer
* @see java.lang.Long
* @see java.math.BigInteger
* @see java.lang.Float
* @see java.lang.Double
* @see java.math.BigDecimal
*/
@SuppressWarnings("unchecked")
public static <T extends Number> T convertNumberToTargetClass(Number number, Class<T> targetClass)
throws IllegalArgumentException {
Assert.notNull(number, "Number must not be null");
Assert.notNull(targetClass, "Target class must not be null");
if (targetClass.isInstance(number)) {
return (T) number;
}
else if (targetClass.equals(Byte.class)) {
long value = number.longValue();
if (value < Byte.MIN_VALUE || value > Byte.MAX_VALUE) {
raiseOverflowException(number, targetClass);
}
return (T) new Byte(number.byteValue());
}
else if (targetClass.equals(Short.class)) {
long value = number.longValue();
if (value < Short.MIN_VALUE || value > Short.MAX_VALUE) {
raiseOverflowException(number, targetClass);
}
return (T) new Short(number.shortValue());
}
else if (targetClass.equals(Integer.class)) {
long value = number.longValue();
if (value < Integer.MIN_VALUE || value > Integer.MAX_VALUE) {
raiseOverflowException(number, targetClass);
}
return (T) new Integer(number.intValue());
}
else if (targetClass.equals(Long.class)) {
return (T) new Long(number.longValue());
}
else if (targetClass.equals(BigInteger.class)) {
if (number instanceof BigDecimal) {
// do not lose precision - use BigDecimal's own conversion
return (T) ((BigDecimal) number).toBigInteger();
}
else {
// original value is not a Big* number - use standard long conversion
return (T) BigInteger.valueOf(number.longValue());
}
}
else if (targetClass.equals(Float.class)) {
return (T) new Float(number.floatValue());
}
else if (targetClass.equals(Double.class)) {
return (T) new Double(number.doubleValue());
}
else if (targetClass.equals(BigDecimal.class)) {
// always use BigDecimal(String) here to avoid unpredictability of BigDecimal(double)
// (see BigDecimal javadoc for details)
return (T) new BigDecimal(number.toString());
}
else {
throw new IllegalArgumentException("Could not convert number [" + number + "] of type [" +
number.getClass().getName() + "] to unknown target class [" + targetClass.getName() + "]");
}
}
/**
* Raise an overflow exception for the given number and target class.
* @param number the number we tried to convert
* @param targetClass the target class we tried to convert to
*/
private static void raiseOverflowException(Number number, Class targetClass) {
throw new IllegalArgumentException("Could not convert number [" + number + "] of type [" +
number.getClass().getName() + "] to target class [" + targetClass.getName() + "]: overflow");
}
/**
* Parse the given text into a number instance of the given target class,
* using the corresponding <code>decode</code> / <code>valueOf</code> methods.
* <p>Trims the input <code>String</code> before attempting to parse the number.
* Supports numbers in hex format (with leading "0x", "0X" or "#") as well.
* @param text the text to convert
* @param targetClass the target class to parse into
* @return the parsed number
* @throws IllegalArgumentException if the target class is not supported
* (i.e. not a standard Number subclass as included in the JDK)
* @see java.lang.Byte#decode
* @see java.lang.Short#decode
* @see java.lang.Integer#decode
* @see java.lang.Long#decode
* @see #decodeBigInteger(String)
* @see java.lang.Float#valueOf
* @see java.lang.Double#valueOf
* @see java.math.BigDecimal#BigDecimal(String)
*/
@SuppressWarnings("unchecked")
public static <T extends Number> T parseNumber(String text, Class<T> targetClass) {
Assert.notNull(text, "Text must not be null");
Assert.notNull(targetClass, "Target class must not be null");
String trimmed = StringUtils.trimAllWhitespace(text);
if (targetClass.equals(Byte.class)) {
return (T) (isHexNumber(trimmed) ? Byte.decode(trimmed) : Byte.valueOf(trimmed));
}
else if (targetClass.equals(Short.class)) {
return (T) (isHexNumber(trimmed) ? Short.decode(trimmed) : Short.valueOf(trimmed));
}
else if (targetClass.equals(Integer.class)) {
return (T) (isHexNumber(trimmed) ? Integer.decode(trimmed) : Integer.valueOf(trimmed));
}
else if (targetClass.equals(Long.class)) {
return (T) (isHexNumber(trimmed) ? Long.decode(trimmed) : Long.valueOf(trimmed));
}
else if (targetClass.equals(BigInteger.class)) {
return (T) (isHexNumber(trimmed) ? decodeBigInteger(trimmed) : new BigInteger(trimmed));
}
else if (targetClass.equals(Float.class)) {
return (T) Float.valueOf(trimmed);
}
else if (targetClass.equals(Double.class)) {
return (T) Double.valueOf(trimmed);
}
else if (targetClass.equals(BigDecimal.class) || targetClass.equals(Number.class)) {
return (T) new BigDecimal(trimmed);
}
else {
throw new IllegalArgumentException(
"Cannot convert String [" + text + "] to target class [" + targetClass.getName() + "]");
}
}
/**
* Parse the given text into a number instance of the given target class,
* using the given NumberFormat. Trims the input <code>String</code>
* before attempting to parse the number.
* @param text the text to convert
* @param targetClass the target class to parse into
* @param numberFormat the NumberFormat to use for parsing (if <code>null</code>,
* this method falls back to <code>parseNumber(String, Class)</code>)
* @return the parsed number
* @throws IllegalArgumentException if the target class is not supported
* (i.e. not a standard Number subclass as included in the JDK)
* @see java.text.NumberFormat#parse
* @see #convertNumberToTargetClass
* @see #parseNumber(String, Class)
*/
public static <T extends Number> T parseNumber(String text, Class<T> targetClass, NumberFormat numberFormat) {
if (numberFormat != null) {
Assert.notNull(text, "Text must not be null");
Assert.notNull(targetClass, "Target class must not be null");
DecimalFormat decimalFormat = null;
boolean resetBigDecimal = false;
if (numberFormat instanceof DecimalFormat) {
decimalFormat = (DecimalFormat) numberFormat;
if (BigDecimal.class.equals(targetClass) && !decimalFormat.isParseBigDecimal()) {
decimalFormat.setParseBigDecimal(true);
resetBigDecimal = true;
}
}
try {
Number number = numberFormat.parse(StringUtils.trimAllWhitespace(text));
return convertNumberToTargetClass(number, targetClass);
}
catch (ParseException ex) {
throw new IllegalArgumentException("Could not parse number: " + ex.getMessage());
}
finally {
if (resetBigDecimal) {
decimalFormat.setParseBigDecimal(false);
}
}
}
else {
return parseNumber(text, targetClass);
}
}
/**
* Determine whether the given value String indicates a hex number, i.e. needs to be
* passed into <code>Integer.decode</code> instead of <code>Integer.valueOf</code> (etc).
*/
private static boolean isHexNumber(String value) {
int index = (value.startsWith("-") ? 1 : 0);
return (value.startsWith("0x", index) || value.startsWith("0X", index) || value.startsWith("#", index));
}
/**
* Decode a {@link java.math.BigInteger} from a {@link String} value.
* Supports decimal, hex and octal notation.
* @see BigInteger#BigInteger(String, int)
*/
private static BigInteger decodeBigInteger(String value) {
int radix = 10;
int index = 0;
boolean negative = false;
// Handle minus sign, if present.
if (value.startsWith("-")) {
negative = true;
index++;
}
// Handle radix specifier, if present.
if (value.startsWith("0x", index) || value.startsWith("0X", index)) {
index += 2;
radix = 16;
}
else if (value.startsWith("#", index)) {
index++;
radix = 16;
}
else if (value.startsWith("0", index) && value.length() > 1 + index) {
index++;
radix = 8;
}
BigInteger result = new BigInteger(value.substring(index), radix);
return (negative ? result.negate() : result);
}
}