com.alibaba.antx.util.NumberUtil Maven / Gradle / Ivy
/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* 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 com.alibaba.antx.util;
import java.math.BigDecimal;
import java.math.BigInteger;
public class NumberUtil {
/**
* Convert a String to a Float
*
* @param val a String to convert
* @return converted Float
* @throws NumberFormatException if the value cannot be converted
*/
public static Float createFloat(String val) {
return Float.valueOf(val);
}
/**
* Convert a String to a Double
*
* @param val a String to convert
* @return converted Double
* @throws NumberFormatException if the value cannot be converted
*/
public static Double createDouble(String val) {
return Double.valueOf(val);
}
/**
* Convert a String to a Integer, handling hex and octal notations.
*
* @param val a String to convert
* @return converted Integer
* @throws NumberFormatException if the value cannot be converted
*/
public static Integer createInteger(String val) {
// decode() handles 0xAABD and 0777 (hex and octal) as well.
return Integer.decode(val);
}
/**
* Convert a String to a Long
*
* @param val a String to convert
* @return converted Long
* @throws NumberFormatException if the value cannot be converted
*/
public static Long createLong(String val) {
return Long.valueOf(val);
}
/**
* Convert a String to a BigInteger
*
* @param val a String to convert
* @return converted BigInteger
* @throws NumberFormatException if the value cannot be converted
*/
public static BigInteger createBigInteger(String val) {
BigInteger bi = new BigInteger(val);
return bi;
}
/**
* Convert a String to a BigDecimal
*
* @param val a String to convert
* @return converted BigDecimal
* @throws NumberFormatException if the value cannot be converted
*/
public static BigDecimal createBigDecimal(String val) {
BigDecimal bd = new BigDecimal(val);
return bd;
}
/**
*
* Turns a string value into a java.lang.Number. First, the value is
* examined for a type qualifier on the end (
* 'f','F','d','D','l','L'). If it is found, it starts trying
* to create succissively larger types from the type specified until one is
* found that can hold the value.
*
*
* If a type specifier is not found, it will check for a decimal point and
* then try successively larger types from Integer to BigInteger and from
* Float to BigDecimal.
*
*
* If the string starts with "0x" or "-0x", it will be interpreted as a
* hexadecimal integer. Values with leading 0's will not be interpreted as
* octal.
*
*
* @param val String containing a number
* @return Number created from the string
* @throws NumberFormatException if the value cannot be converted
*/
public static Number createNumber(String val) throws NumberFormatException {
if (val == null) {
return null;
}
if (val.length() == 0) {
throw new NumberFormatException("\"\" is not a valid number.");
}
if (val.startsWith("--")) {
// this is protection for poorness in java.lang.BigDecimal.
// it accepts this as a legal value, but it does not appear
// to be in specification of class. OS X Java parses it to
// a wrong value.
return null;
}
if (val.startsWith("0x") || val.startsWith("-0x")) {
return createInteger(val);
}
char lastChar = val.charAt(val.length() - 1);
String mant;
String dec;
String exp;
int decPos = val.indexOf('.');
int expPos = val.indexOf('e') + val.indexOf('E') + 1;
if (decPos > -1) {
if (expPos > -1) {
if (expPos < decPos) {
throw new NumberFormatException(val + " is not a valid number.");
}
dec = val.substring(decPos + 1, expPos);
} else {
dec = val.substring(decPos + 1);
}
mant = val.substring(0, decPos);
} else {
if (expPos > -1) {
mant = val.substring(0, expPos);
} else {
mant = val;
}
dec = null;
}
if (!Character.isDigit(lastChar)) {
if (expPos > -1 && expPos < val.length() - 1) {
exp = val.substring(expPos + 1, val.length() - 1);
} else {
exp = null;
}
//Requesting a specific type..
String numeric = val.substring(0, val.length() - 1);
boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
switch (lastChar) {
case 'l':
case 'L':
if (dec == null && exp == null && isDigits(numeric.substring(1))
&& (numeric.charAt(0) == '-' || Character.isDigit(numeric.charAt(0)))) {
try {
return createLong(numeric);
} catch (NumberFormatException nfe) {
//Too big for a long
}
return createBigInteger(numeric);
}
throw new NumberFormatException(val + " is not a valid number.");
case 'f':
case 'F':
try {
Float f = createFloat(numeric);
if (!(f.isInfinite() || f.floatValue() == 0.0F && !allZeros)) {
//If it's too big for a float or the float value = 0 and the string
//has non-zeros in it, then float doens't have the presision we want
return f;
}
} catch (NumberFormatException nfe) {
}
//Fall through
case 'd':
case 'D':
try {
Double d = createDouble(numeric);
if (!(d.isInfinite() || d.floatValue() == 0.0D && !allZeros)) {
return d;
}
} catch (NumberFormatException nfe) {
}
try {
return createBigDecimal(numeric);
} catch (NumberFormatException e) {
}
//Fall through
default:
throw new NumberFormatException(val + " is not a valid number.");
}
} else {
//User doesn't have a preference on the return type, so let's start
//small and go from there...
if (expPos > -1 && expPos < val.length() - 1) {
exp = val.substring(expPos + 1, val.length());
} else {
exp = null;
}
if (dec == null && exp == null) {
//Must be an int,long,bigint
try {
return createInteger(val);
} catch (NumberFormatException nfe) {
}
try {
return createLong(val);
} catch (NumberFormatException nfe) {
}
return createBigInteger(val);
} else {
//Must be a float,double,BigDec
boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
try {
Float f = createFloat(val);
if (!(f.isInfinite() || f.floatValue() == 0.0F && !allZeros)) {
return f;
}
} catch (NumberFormatException nfe) {
}
try {
Double d = createDouble(val);
if (!(d.isInfinite() || d.doubleValue() == 0.0D && !allZeros)) {
return d;
}
} catch (NumberFormatException nfe) {
}
return createBigDecimal(val);
}
}
}
/**
* Checks whether the String contains only digit characters. Null and blank
* string will return false.
*
* @param str the string to check
* @return boolean contains only unicode numeric
*/
public static boolean isDigits(String str) {
if (str == null || str.length() == 0) {
return false;
}
for (int i = 0; i < str.length(); i++) {
if (!Character.isDigit(str.charAt(i))) {
return false;
}
}
return true;
}
/**
* Utility method for createNumber. Returns true if s is null
*
* @param s the String to check
* @return if it is all zeros or null
*/
private static boolean isAllZeros(String s) {
if (s == null) {
return true;
}
for (int i = s.length() - 1; i >= 0; i--) {
if (s.charAt(i) != '0') {
return false;
}
}
return s.length() > 0;
}
}
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