org.springframework.util.NumberUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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 org.springframework.util;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.text.ParseException;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import org.springframework.lang.Nullable;
/**
* Miscellaneous utility methods for number conversion and parsing.
* Mainly for internal use within the framework; consider Apache's
* Commons Lang for a more comprehensive suite of number utilities.
*
* @author Juergen Hoeller
* @author Rob Harrop
* @since 1.1.2
*/
public abstract class NumberUtils {
private static final BigInteger LONG_MIN = BigInteger.valueOf(Long.MIN_VALUE);
private static final BigInteger LONG_MAX = BigInteger.valueOf(Long.MAX_VALUE);
/**
* Standard number types (all immutable):
* Byte, Short, Integer, Long, BigInteger, Float, Double, BigDecimal.
*/
public static final Set> STANDARD_NUMBER_TYPES;
static {
Set> numberTypes = new HashSet<>(8);
numberTypes.add(Byte.class);
numberTypes.add(Short.class);
numberTypes.add(Integer.class);
numberTypes.add(Long.class);
numberTypes.add(BigInteger.class);
numberTypes.add(Float.class);
numberTypes.add(Double.class);
numberTypes.add(BigDecimal.class);
STANDARD_NUMBER_TYPES = Collections.unmodifiableSet(numberTypes);
}
/**
* 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 convertNumberToTargetClass(Number number, Class 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 (Byte.class == targetClass) {
long value = checkedLongValue(number, targetClass);
if (value < Byte.MIN_VALUE || value > Byte.MAX_VALUE) {
raiseOverflowException(number, targetClass);
}
return (T) Byte.valueOf(number.byteValue());
}
else if (Short.class == targetClass) {
long value = checkedLongValue(number, targetClass);
if (value < Short.MIN_VALUE || value > Short.MAX_VALUE) {
raiseOverflowException(number, targetClass);
}
return (T) Short.valueOf(number.shortValue());
}
else if (Integer.class == targetClass) {
long value = checkedLongValue(number, targetClass);
if (value < Integer.MIN_VALUE || value > Integer.MAX_VALUE) {
raiseOverflowException(number, targetClass);
}
return (T) Integer.valueOf(number.intValue());
}
else if (Long.class == targetClass) {
long value = checkedLongValue(number, targetClass);
return (T) Long.valueOf(value);
}
else if (BigInteger.class == targetClass) {
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 (Float.class == targetClass) {
return (T) Float.valueOf(number.floatValue());
}
else if (Double.class == targetClass) {
return (T) Double.valueOf(number.doubleValue());
}
else if (BigDecimal.class == targetClass) {
// 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 unsupported target class [" + targetClass.getName() + "]");
}
}
/**
* Check for a {@code BigInteger}/{@code BigDecimal} long overflow
* before returning the given number as a long value.
* @param number the number to convert
* @param targetClass the target class to convert to
* @return the long value, if convertible without overflow
* @throws IllegalArgumentException if there is an overflow
* @see #raiseOverflowException
*/
private static long checkedLongValue(Number number, Class targetClass) {
BigInteger bigInt = null;
if (number instanceof BigInteger) {
bigInt = (BigInteger) number;
}
else if (number instanceof BigDecimal) {
bigInt = ((BigDecimal) number).toBigInteger();
}
// Effectively analogous to JDK 8's BigInteger.longValueExact()
if (bigInt != null && (bigInt.compareTo(LONG_MIN) < 0 || bigInt.compareTo(LONG_MAX) > 0)) {
raiseOverflowException(number, targetClass);
}
return number.longValue();
}
/**
* 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
* @throws IllegalArgumentException if there is an overflow
*/
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 {@code text} into a {@link Number} instance of the given
* target class, using the corresponding {@code decode} / {@code valueOf} method.
* Trims all whitespace (leading, trailing, and in between characters) from
* the input {@code String} 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 Byte#decode
* @see Short#decode
* @see Integer#decode
* @see Long#decode
* @see #decodeBigInteger(String)
* @see Float#valueOf
* @see Double#valueOf
* @see java.math.BigDecimal#BigDecimal(String)
*/
@SuppressWarnings("unchecked")
public static T parseNumber(String text, Class targetClass) {
Assert.notNull(text, "Text must not be null");
Assert.notNull(targetClass, "Target class must not be null");
String trimmed = StringUtils.trimAllWhitespace(text);
if (Byte.class == targetClass) {
return (T) (isHexNumber(trimmed) ? Byte.decode(trimmed) : Byte.valueOf(trimmed));
}
else if (Short.class == targetClass) {
return (T) (isHexNumber(trimmed) ? Short.decode(trimmed) : Short.valueOf(trimmed));
}
else if (Integer.class == targetClass) {
return (T) (isHexNumber(trimmed) ? Integer.decode(trimmed) : Integer.valueOf(trimmed));
}
else if (Long.class == targetClass) {
return (T) (isHexNumber(trimmed) ? Long.decode(trimmed) : Long.valueOf(trimmed));
}
else if (BigInteger.class == targetClass) {
return (T) (isHexNumber(trimmed) ? decodeBigInteger(trimmed) : new BigInteger(trimmed));
}
else if (Float.class == targetClass) {
return (T) Float.valueOf(trimmed);
}
else if (Double.class == targetClass) {
return (T) Double.valueOf(trimmed);
}
else if (BigDecimal.class == targetClass || Number.class == targetClass) {
return (T) new BigDecimal(trimmed);
}
else {
throw new IllegalArgumentException(
"Cannot convert String [" + text + "] to target class [" + targetClass.getName() + "]");
}
}
/**
* Parse the given {@code text} into a {@link Number} instance of the
* given target class, using the supplied {@link NumberFormat}.
* Trims the input {@code String} before attempting to parse the number.
* @param text the text to convert
* @param targetClass the target class to parse into
* @param numberFormat the {@code NumberFormat} to use for parsing (if
* {@code null}, this method falls back to {@link #parseNumber(String, Class)})
* @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 parseNumber(
String text, Class targetClass, @Nullable 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 == 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 {@code value} String indicates a hex number,
* i.e. needs to be passed into {@code Integer.decode} instead of
* {@code Integer.valueOf}, 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 the supplied {@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);
}
}