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Commons.Lang, a package of Java utility classes for the
classes that are in java.lang's hierarchy, or are considered to be so
standard as to justify existence in java.lang.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.commons.lang.math;
import java.math.BigDecimal;
import java.math.BigInteger;
import org.apache.commons.lang.StringUtils;
/**
* Provides extra functionality for Java Number classes.
*
* @author Henri Yandell
* @author Rand McNeely
* @author Stephen Colebourne
* @author Steve Downey
* @author Eric Pugh
* @author Phil Steitz
* @author Matthew Hawthorne
* @author Gary Gregory
* @author Fredrik Westermarck
* @since 2.0
* @version $Id: NumberUtils.java 437554 2006-08-28 06:21:41Z bayard $
*/
public class NumberUtils {
/** Reusable Long constant for zero. */
public static final Long LONG_ZERO = new Long(0L);
/** Reusable Long constant for one. */
public static final Long LONG_ONE = new Long(1L);
/** Reusable Long constant for minus one. */
public static final Long LONG_MINUS_ONE = new Long(-1L);
/** Reusable Integer constant for zero. */
public static final Integer INTEGER_ZERO = new Integer(0);
/** Reusable Integer constant for one. */
public static final Integer INTEGER_ONE = new Integer(1);
/** Reusable Integer constant for minus one. */
public static final Integer INTEGER_MINUS_ONE = new Integer(-1);
/** Reusable Short constant for zero. */
public static final Short SHORT_ZERO = new Short((short) 0);
/** Reusable Short constant for one. */
public static final Short SHORT_ONE = new Short((short) 1);
/** Reusable Short constant for minus one. */
public static final Short SHORT_MINUS_ONE = new Short((short) -1);
/** Reusable Byte constant for zero. */
public static final Byte BYTE_ZERO = new Byte((byte) 0);
/** Reusable Byte constant for one. */
public static final Byte BYTE_ONE = new Byte((byte) 1);
/** Reusable Byte constant for minus one. */
public static final Byte BYTE_MINUS_ONE = new Byte((byte) -1);
/** Reusable Double constant for zero. */
public static final Double DOUBLE_ZERO = new Double(0.0d);
/** Reusable Double constant for one. */
public static final Double DOUBLE_ONE = new Double(1.0d);
/** Reusable Double constant for minus one. */
public static final Double DOUBLE_MINUS_ONE = new Double(-1.0d);
/** Reusable Float constant for zero. */
public static final Float FLOAT_ZERO = new Float(0.0f);
/** Reusable Float constant for one. */
public static final Float FLOAT_ONE = new Float(1.0f);
/** Reusable Float constant for minus one. */
public static final Float FLOAT_MINUS_ONE = new Float(-1.0f);
/**
* NumberUtils instances should NOT be constructed in standard programming.
* Instead, the class should be used as NumberUtils.stringToInt("6");.
*
* This constructor is public to permit tools that require a JavaBean instance
* to operate.
*/
public NumberUtils() {
super();
}
//-----------------------------------------------------------------------
/**
* Convert a String to an int, returning
* zero if the conversion fails.
*
* If the string is null, zero is returned.
*
*
* NumberUtils.stringToInt(null) = 0
* NumberUtils.stringToInt("") = 0
* NumberUtils.stringToInt("1") = 1
*
*
* @param str the string to convert, may be null
* @return the int represented by the string, or zero if
* conversion fails
* @deprecated Use {@link #toInt(String)}
* This method will be removed in Commons Lang 3.0
*/
public static int stringToInt(String str) {
return toInt(str);
}
/**
* Convert a String to an int, returning
* zero if the conversion fails.
*
* If the string is null, zero is returned.
*
*
* NumberUtils.toInt(null) = 0
* NumberUtils.toInt("") = 0
* NumberUtils.toInt("1") = 1
*
*
* @param str the string to convert, may be null
* @return the int represented by the string, or zero if
* conversion fails
* @since 2.1
*/
public static int toInt(String str) {
return toInt(str, 0);
}
/**
* Convert a String to an int, returning a
* default value if the conversion fails.
*
* If the string is null, the default value is returned.
*
*
* NumberUtils.stringToInt(null, 1) = 1
* NumberUtils.stringToInt("", 1) = 1
* NumberUtils.stringToInt("1", 0) = 1
*
*
* @param str the string to convert, may be null
* @param defaultValue the default value
* @return the int represented by the string, or the default if conversion fails
* @deprecated Use {@link #toInt(String, int)}
* This method will be removed in Commons Lang 3.0
*/
public static int stringToInt(String str, int defaultValue) {
return toInt(str, defaultValue);
}
/**
* Convert a String to an int, returning a
* default value if the conversion fails.
*
* If the string is null, the default value is returned.
*
*
* NumberUtils.toInt(null, 1) = 1
* NumberUtils.toInt("", 1) = 1
* NumberUtils.toInt("1", 0) = 1
*
*
* @param str the string to convert, may be null
* @param defaultValue the default value
* @return the int represented by the string, or the default if conversion fails
* @since 2.1
*/
public static int toInt(String str, int defaultValue) {
if(str == null) {
return defaultValue;
}
try {
return Integer.parseInt(str);
} catch (NumberFormatException nfe) {
return defaultValue;
}
}
/**
* Convert a String to a long, returning
* zero if the conversion fails.
*
* If the string is null, zero is returned.
*
*
* NumberUtils.toLong(null) = 0L
* NumberUtils.toLong("") = 0L
* NumberUtils.toLong("1") = 1L
*
*
* @param str the string to convert, may be null
* @return the long represented by the string, or 0 if
* conversion fails
* @since 2.1
*/
public static long toLong(String str) {
return toLong(str, 0L);
}
/**
* Convert a String to a long, returning a
* default value if the conversion fails.
*
* If the string is null, the default value is returned.
*
*
* NumberUtils.toLong(null, 1L) = 1L
* NumberUtils.toLong("", 1L) = 1L
* NumberUtils.toLong("1", 0L) = 1L
*
*
* @param str the string to convert, may be null
* @param defaultValue the default value
* @return the long represented by the string, or the default if conversion fails
* @since 2.1
*/
public static long toLong(String str, long defaultValue) {
if (str == null) {
return defaultValue;
}
try {
return Long.parseLong(str);
} catch (NumberFormatException nfe) {
return defaultValue;
}
}
/**
* Convert a String to a float, returning
* 0.0f if the conversion fails.
*
* If the string str is null,
* 0.0f is returned.
*
*
* NumberUtils.toFloat(null) = 0.0f
* NumberUtils.toFloat("") = 0.0f
* NumberUtils.toFloat("1.5") = 1.5f
*
*
* @param str the string to convert, may be null
* @return the float represented by the string, or 0.0f
* if conversion fails
* @since 2.1
*/
public static float toFloat(String str) {
return toFloat(str, 0.0f);
}
/**
* Convert a String to a float, returning a
* default value if the conversion fails.
*
* If the string str is null, the default
* value is returned.
*
*
* NumberUtils.toFloat(null, 1.1f) = 1.0f
* NumberUtils.toFloat("", 1.1f) = 1.1f
* NumberUtils.toFloat("1.5", 0.0f) = 1.5f
*
*
* @param str the string to convert, may be null
* @param defaultValue the default value
* @return the float represented by the string, or defaultValue
* if conversion fails
* @since 2.1
*/
public static float toFloat(String str, float defaultValue) {
if (str == null) {
return defaultValue;
}
try {
return Float.parseFloat(str);
} catch (NumberFormatException nfe) {
return defaultValue;
}
}
/**
* Convert a String to a double, returning
* 0.0d if the conversion fails.
*
* If the string str is null,
* 0.0d is returned.
*
*
* NumberUtils.toDouble(null) = 0.0d
* NumberUtils.toDouble("") = 0.0d
* NumberUtils.toDouble("1.5") = 1.5d
*
*
* @param str the string to convert, may be null
* @return the double represented by the string, or 0.0d
* if conversion fails
* @since 2.1
*/
public static double toDouble(String str) {
return toDouble(str, 0.0d);
}
/**
* Convert a String to a double, returning a
* default value if the conversion fails.
*
* If the string str is null, the default
* value is returned.
*
*
* NumberUtils.toDouble(null, 1.1d) = 1.1d
* NumberUtils.toDouble("", 1.1d) = 1.1d
* NumberUtils.toDouble("1.5", 0.0d) = 1.5d
*
*
* @param str the string to convert, may be null
* @param defaultValue the default value
* @return the double represented by the string, or defaultValue
* if conversion fails
* @since 2.1
*/
public static double toDouble(String str, double defaultValue) {
if (str == null) {
return defaultValue;
}
try {
return Double.parseDouble(str);
} catch (NumberFormatException nfe) {
return defaultValue;
}
}
//-----------------------------------------------------------------------
// must handle Long, Float, Integer, Float, Short,
// BigDecimal, BigInteger and Byte
// useful methods:
// Byte.decode(String)
// Byte.valueOf(String,int radix)
// Byte.valueOf(String)
// Double.valueOf(String)
// Float.valueOf(String)
// new Float(String)
// Integer.valueOf(String,int radix)
// Integer.valueOf(String)
// Integer.decode(String)
// Integer.getInteger(String)
// Integer.getInteger(String,int val)
// Integer.getInteger(String,Integer val)
// new Integer(String)
// new Double(String)
// new Byte(String)
// new Long(String)
// Long.getLong(String)
// Long.getLong(String,int)
// Long.getLong(String,Integer)
// Long.valueOf(String,int)
// Long.valueOf(String)
// new Short(String)
// Short.decode(String)
// Short.valueOf(String,int)
// Short.valueOf(String)
// new BigDecimal(String)
// new BigInteger(String)
// new BigInteger(String,int radix)
// Possible inputs:
// 45 45.5 45E7 4.5E7 Hex Oct Binary xxxF xxxD xxxf xxxd
// plus minus everything. Prolly more. A lot are not separable.
/**
* 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 successively larger types from the type specified
* until one is found that can represent 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.
*
* Returns null if the string is null.
*
* This method does not trim the input string, i.e., strings with leading
* or trailing spaces will generate NumberFormatExceptions.
*
* @param str String containing a number, may be null
* @return Number created from the string
* @throws NumberFormatException if the value cannot be converted
*/
public static Number createNumber(String str) throws NumberFormatException {
if (str == null) {
return null;
}
if (StringUtils.isBlank(str)) {
throw new NumberFormatException("A blank string is not a valid number");
}
if (str.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 (str.startsWith("0x") || str.startsWith("-0x")) {
return createInteger(str);
}
char lastChar = str.charAt(str.length() - 1);
String mant;
String dec;
String exp;
int decPos = str.indexOf('.');
int expPos = str.indexOf('e') + str.indexOf('E') + 1;
if (decPos > -1) {
if (expPos > -1) {
if (expPos < decPos) {
throw new NumberFormatException(str + " is not a valid number.");
}
dec = str.substring(decPos + 1, expPos);
} else {
dec = str.substring(decPos + 1);
}
mant = str.substring(0, decPos);
} else {
if (expPos > -1) {
mant = str.substring(0, expPos);
} else {
mant = str;
}
dec = null;
}
if (!Character.isDigit(lastChar)) {
if (expPos > -1 && expPos < str.length() - 1) {
exp = str.substring(expPos + 1, str.length() - 1);
} else {
exp = null;
}
//Requesting a specific type..
String numeric = str.substring(0, str.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(str + " is not a valid number.");
case 'f' :
case 'F' :
try {
Float f = NumberUtils.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 does not have the precision we want
return f;
}
} catch (NumberFormatException nfe) {
// ignore the bad number
}
//Fall through
case 'd' :
case 'D' :
try {
Double d = NumberUtils.createDouble(numeric);
if (!(d.isInfinite() || (d.floatValue() == 0.0D && !allZeros))) {
return d;
}
} catch (NumberFormatException nfe) {
// ignore the bad number
}
try {
return createBigDecimal(numeric);
} catch (NumberFormatException e) {
// ignore the bad number
}
//Fall through
default :
throw new NumberFormatException(str + " 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 < str.length() - 1) {
exp = str.substring(expPos + 1, str.length());
} else {
exp = null;
}
if (dec == null && exp == null) {
//Must be an int,long,bigint
try {
return createInteger(str);
} catch (NumberFormatException nfe) {
// ignore the bad number
}
try {
return createLong(str);
} catch (NumberFormatException nfe) {
// ignore the bad number
}
return createBigInteger(str);
} else {
//Must be a float,double,BigDec
boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
try {
Float f = createFloat(str);
if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) {
return f;
}
} catch (NumberFormatException nfe) {
// ignore the bad number
}
try {
Double d = createDouble(str);
if (!(d.isInfinite() || (d.doubleValue() == 0.0D && !allZeros))) {
return d;
}
} catch (NumberFormatException nfe) {
// ignore the bad number
}
return createBigDecimal(str);
}
}
}
/**
* Utility method for {@link #createNumber(java.lang.String)}.
*
* Returns true if s is null.
*
* @param str the String to check
* @return if it is all zeros or null
*/
private static boolean isAllZeros(String str) {
if (str == null) {
return true;
}
for (int i = str.length() - 1; i >= 0; i--) {
if (str.charAt(i) != '0') {
return false;
}
}
return str.length() > 0;
}
//-----------------------------------------------------------------------
/**
* Convert a String to a Float.
*
* Returns null if the string is null.
*
* @param str a String to convert, may be null
* @return converted Float
* @throws NumberFormatException if the value cannot be converted
*/
public static Float createFloat(String str) {
if (str == null) {
return null;
}
return Float.valueOf(str);
}
/**
* Convert a String to a Double.
*
* Returns null if the string is null.
*
* @param str a String to convert, may be null
* @return converted Double
* @throws NumberFormatException if the value cannot be converted
*/
public static Double createDouble(String str) {
if (str == null) {
return null;
}
return Double.valueOf(str);
}
/**
* Convert a String to a Integer, handling
* hex and octal notations.
*
* Returns null if the string is null.
*
* @param str a String to convert, may be null
* @return converted Integer
* @throws NumberFormatException if the value cannot be converted
*/
public static Integer createInteger(String str) {
if (str == null) {
return null;
}
// decode() handles 0xAABD and 0777 (hex and octal) as well.
return Integer.decode(str);
}
/**
* Convert a String to a Long.
*
* Returns null if the string is null.
*
* @param str a String to convert, may be null
* @return converted Long
* @throws NumberFormatException if the value cannot be converted
*/
public static Long createLong(String str) {
if (str == null) {
return null;
}
return Long.valueOf(str);
}
/**
* Convert a String to a BigInteger.
*
* Returns null if the string is null.
*
* @param str a String to convert, may be null
* @return converted BigInteger
* @throws NumberFormatException if the value cannot be converted
*/
public static BigInteger createBigInteger(String str) {
if (str == null) {
return null;
}
return new BigInteger(str);
}
/**
* Convert a String to a BigDecimal.
*
* Returns null if the string is null.
*
* @param str a String to convert, may be null
* @return converted BigDecimal
* @throws NumberFormatException if the value cannot be converted
*/
public static BigDecimal createBigDecimal(String str) {
if (str == null) {
return null;
}
// handle JDK1.3.1 bug where "" throws IndexOutOfBoundsException
if (StringUtils.isBlank(str)) {
throw new NumberFormatException("A blank string is not a valid number");
}
return new BigDecimal(str);
}
// Min in array
//--------------------------------------------------------------------
/**
* Returns the minimum value in an array.
*
* @param array an array, must not be null or empty
* @return the minimum value in the array
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if array is empty
*/
public static long min(long[] array) {
// Validates input
if (array == null) {
throw new IllegalArgumentException("The Array must not be null");
} else if (array.length == 0) {
throw new IllegalArgumentException("Array cannot be empty.");
}
// Finds and returns min
long min = array[0];
for (int i = 1; i < array.length; i++) {
if (array[i] < min) {
min = array[i];
}
}
return min;
}
/**
* Returns the minimum value in an array.
*
* @param array an array, must not be null or empty
* @return the minimum value in the array
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if array is empty
*/
public static int min(int[] array) {
// Validates input
if (array == null) {
throw new IllegalArgumentException("The Array must not be null");
} else if (array.length == 0) {
throw new IllegalArgumentException("Array cannot be empty.");
}
// Finds and returns min
int min = array[0];
for (int j = 1; j < array.length; j++) {
if (array[j] < min) {
min = array[j];
}
}
return min;
}
/**
* Returns the minimum value in an array.
*
* @param array an array, must not be null or empty
* @return the minimum value in the array
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if array is empty
*/
public static short min(short[] array) {
// Validates input
if (array == null) {
throw new IllegalArgumentException("The Array must not be null");
} else if (array.length == 0) {
throw new IllegalArgumentException("Array cannot be empty.");
}
// Finds and returns min
short min = array[0];
for (int i = 1; i < array.length; i++) {
if (array[i] < min) {
min = array[i];
}
}
return min;
}
/**
* Returns the minimum value in an array.
*
* @param array an array, must not be null or empty
* @return the minimum value in the array
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if array is empty
*/
public static double min(double[] array) {
// Validates input
if (array == null) {
throw new IllegalArgumentException("The Array must not be null");
} else if (array.length == 0) {
throw new IllegalArgumentException("Array cannot be empty.");
}
// Finds and returns min
double min = array[0];
for (int i = 1; i < array.length; i++) {
if (array[i] < min) {
min = array[i];
}
}
return min;
}
/**
* Returns the minimum value in an array.
*
* @param array an array, must not be null or empty
* @return the minimum value in the array
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if array is empty
*/
public static float min(float[] array) {
// Validates input
if (array == null) {
throw new IllegalArgumentException("The Array must not be null");
} else if (array.length == 0) {
throw new IllegalArgumentException("Array cannot be empty.");
}
// Finds and returns min
float min = array[0];
for (int i = 1; i < array.length; i++) {
if (array[i] < min) {
min = array[i];
}
}
return min;
}
// Max in array
//--------------------------------------------------------------------
/**
* Returns the maximum value in an array.
*
* @param array an array, must not be null or empty
* @return the minimum value in the array
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if array is empty
*/
public static long max(long[] array) {
// Validates input
if (array == null) {
throw new IllegalArgumentException("The Array must not be null");
} else if (array.length == 0) {
throw new IllegalArgumentException("Array cannot be empty.");
}
// Finds and returns max
long max = array[0];
for (int j = 1; j < array.length; j++) {
if (array[j] > max) {
max = array[j];
}
}
return max;
}
/**
* Returns the maximum value in an array.
*
* @param array an array, must not be null or empty
* @return the minimum value in the array
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if array is empty
*/
public static int max(int[] array) {
// Validates input
if (array == null) {
throw new IllegalArgumentException("The Array must not be null");
} else if (array.length == 0) {
throw new IllegalArgumentException("Array cannot be empty.");
}
// Finds and returns max
int max = array[0];
for (int j = 1; j < array.length; j++) {
if (array[j] > max) {
max = array[j];
}
}
return max;
}
/**
* Returns the maximum value in an array.
*
* @param array an array, must not be null or empty
* @return the minimum value in the array
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if array is empty
*/
public static short max(short[] array) {
// Validates input
if (array == null) {
throw new IllegalArgumentException("The Array must not be null");
} else if (array.length == 0) {
throw new IllegalArgumentException("Array cannot be empty.");
}
// Finds and returns max
short max = array[0];
for (int i = 1; i < array.length; i++) {
if (array[i] > max) {
max = array[i];
}
}
return max;
}
/**
* Returns the maximum value in an array.
*
* @param array an array, must not be null or empty
* @return the minimum value in the array
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if array is empty
*/
public static double max(double[] array) {
// Validates input
if (array== null) {
throw new IllegalArgumentException("The Array must not be null");
} else if (array.length == 0) {
throw new IllegalArgumentException("Array cannot be empty.");
}
// Finds and returns max
double max = array[0];
for (int j = 1; j < array.length; j++) {
if (array[j] > max) {
max = array[j];
}
}
return max;
}
/**
* Returns the maximum value in an array.
*
* @param array an array, must not be null or empty
* @return the minimum value in the array
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if array is empty
*/
public static float max(float[] array) {
// Validates input
if (array == null) {
throw new IllegalArgumentException("The Array must not be null");
} else if (array.length == 0) {
throw new IllegalArgumentException("Array cannot be empty.");
}
// Finds and returns max
float max = array[0];
for (int j = 1; j < array.length; j++) {
if (array[j] > max) {
max = array[j];
}
}
return max;
}
// 3 param min
//-----------------------------------------------------------------------
/**
* Gets the minimum of three long values.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the smallest of the values
*/
public static long min(long a, long b, long c) {
if (b < a) {
a = b;
}
if (c < a) {
a = c;
}
return a;
}
/**
* Gets the minimum of three int values.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the smallest of the values
*/
public static int min(int a, int b, int c) {
if (b < a) {
a = b;
}
if (c < a) {
a = c;
}
return a;
}
/**
* Gets the minimum of three short values.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the smallest of the values
*/
public static short min(short a, short b, short c) {
if (b < a) {
a = b;
}
if (c < a) {
a = c;
}
return a;
}
/**
* Gets the minimum of three byte values.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the smallest of the values
*/
public static byte min(byte a, byte b, byte c) {
if (b < a) {
a = b;
}
if (c < a) {
a = c;
}
return a;
}
/**
* Gets the minimum of three double values.
*
* If any value is NaN, NaN is
* returned. Infinity is handled.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the smallest of the values
*/
public static double min(double a, double b, double c) {
return Math.min(Math.min(a, b), c);
}
/**
* Gets the minimum of three float values.
*
* If any value is NaN, NaN is
* returned. Infinity is handled.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the smallest of the values
*/
public static float min(float a, float b, float c) {
return Math.min(Math.min(a, b), c);
}
// 3 param max
//-----------------------------------------------------------------------
/**
* Gets the maximum of three long values.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the largest of the values
*/
public static long max(long a, long b, long c) {
if (b > a) {
a = b;
}
if (c > a) {
a = c;
}
return a;
}
/**
* Gets the maximum of three int values.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the largest of the values
*/
public static int max(int a, int b, int c) {
if (b > a) {
a = b;
}
if (c > a) {
a = c;
}
return a;
}
/**
* Gets the maximum of three short values.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the largest of the values
*/
public static short max(short a, short b, short c) {
if (b > a) {
a = b;
}
if (c > a) {
a = c;
}
return a;
}
/**
* Gets the maximum of three byte values.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the largest of the values
*/
public static byte max(byte a, byte b, byte c) {
if (b > a) {
a = b;
}
if (c > a) {
a = c;
}
return a;
}
/**
* Gets the maximum of three double values.
*
* If any value is NaN, NaN is
* returned. Infinity is handled.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the largest of the values
*/
public static double max(double a, double b, double c) {
return Math.max(Math.max(a, b), c);
}
/**
* Gets the maximum of three float values.
*
* If any value is NaN, NaN is
* returned. Infinity is handled.
*
* @param a value 1
* @param b value 2
* @param c value 3
* @return the largest of the values
*/
public static float max(float a, float b, float c) {
return Math.max(Math.max(a, b), c);
}
//-----------------------------------------------------------------------
/**
* Compares two doubles for order.
*
* This method is more comprehensive than the standard Java greater
* than, less than and equals operators.
*
* - It returns
-1 if the first value is less than the second.
* - It returns
+1 if the first value is greater than the second.
* - It returns
0 if the values are equal.
*
*
*
* The ordering is as follows, largest to smallest:
*
* - NaN
*
- Positive infinity
*
- Maximum double
*
- Normal positive numbers
*
- +0.0
*
- -0.0
*
- Normal negative numbers
*
- Minimum double (
-Double.MAX_VALUE)
* - Negative infinity
*
*
*
* Comparing NaN with NaN will
* return 0.
*
* @param lhs the first double
* @param rhs the second double
* @return -1 if lhs is less, +1 if greater,
* 0 if equal to rhs
*/
public static int compare(double lhs, double rhs) {
if (lhs < rhs) {
return -1;
}
if (lhs > rhs) {
return +1;
}
// Need to compare bits to handle 0.0 == -0.0 being true
// compare should put -0.0 < +0.0
// Two NaNs are also == for compare purposes
// where NaN == NaN is false
long lhsBits = Double.doubleToLongBits(lhs);
long rhsBits = Double.doubleToLongBits(rhs);
if (lhsBits == rhsBits) {
return 0;
}
// Something exotic! A comparison to NaN or 0.0 vs -0.0
// Fortunately NaN's long is > than everything else
// Also negzeros bits < poszero
// NAN: 9221120237041090560
// MAX: 9218868437227405311
// NEGZERO: -9223372036854775808
if (lhsBits < rhsBits) {
return -1;
} else {
return +1;
}
}
/**
* Compares two floats for order.
*
* This method is more comprehensive than the standard Java greater than,
* less than and equals operators.
*
* - It returns
-1 if the first value is less than the second.
* - It returns
+1 if the first value is greater than the second.
* - It returns
0 if the values are equal.
*
*
* The ordering is as follows, largest to smallest:
*
* - NaN
*
- Positive infinity
*
- Maximum float
*
- Normal positive numbers
*
- +0.0
*
- -0.0
*
- Normal negative numbers
*
- Minimum float (
-Float.MAX_VALUE)
* - Negative infinity
*
*
* Comparing NaN with NaN will return
* 0.
*
* @param lhs the first float
* @param rhs the second float
* @return -1 if lhs is less, +1 if greater,
* 0 if equal to rhs
*/
public static int compare(float lhs, float rhs) {
if (lhs < rhs) {
return -1;
}
if (lhs > rhs) {
return +1;
}
//Need to compare bits to handle 0.0 == -0.0 being true
// compare should put -0.0 < +0.0
// Two NaNs are also == for compare purposes
// where NaN == NaN is false
int lhsBits = Float.floatToIntBits(lhs);
int rhsBits = Float.floatToIntBits(rhs);
if (lhsBits == rhsBits) {
return 0;
}
//Something exotic! A comparison to NaN or 0.0 vs -0.0
//Fortunately NaN's int is > than everything else
//Also negzeros bits < poszero
//NAN: 2143289344
//MAX: 2139095039
//NEGZERO: -2147483648
if (lhsBits < rhsBits) {
return -1;
} else {
return +1;
}
}
//-----------------------------------------------------------------------
/**
* Checks whether the String contains only
* digit characters.
*
* Null and empty String will return
* false.
*
* @param str the String to check
* @return true if str contains only unicode numeric
*/
public static boolean isDigits(String str) {
if (StringUtils.isEmpty(str)) {
return false;
}
for (int i = 0; i < str.length(); i++) {
if (!Character.isDigit(str.charAt(i))) {
return false;
}
}
return true;
}
/**
* Checks whether the String a valid Java number.
*
* Valid numbers include hexadecimal marked with the 0x
* qualifier, scientific notation and numbers marked with a type
* qualifier (e.g. 123L).
*
* Null and empty String will return
* false.
*
* @param str the String to check
* @return true if the string is a correctly formatted number
*/
public static boolean isNumber(String str) {
if (StringUtils.isEmpty(str)) {
return false;
}
char[] chars = str.toCharArray();
int sz = chars.length;
boolean hasExp = false;
boolean hasDecPoint = false;
boolean allowSigns = false;
boolean foundDigit = false;
// deal with any possible sign up front
int start = (chars[0] == '-') ? 1 : 0;
if (sz > start + 1) {
if (chars[start] == '0' && chars[start + 1] == 'x') {
int i = start + 2;
if (i == sz) {
return false; // str == "0x"
}
// checking hex (it can't be anything else)
for (; i < chars.length; i++) {
if ((chars[i] < '0' || chars[i] > '9')
&& (chars[i] < 'a' || chars[i] > 'f')
&& (chars[i] < 'A' || chars[i] > 'F')) {
return false;
}
}
return true;
}
}
sz--; // don't want to loop to the last char, check it afterwords
// for type qualifiers
int i = start;
// loop to the next to last char or to the last char if we need another digit to
// make a valid number (e.g. chars[0..5] = "1234E")
while (i < sz || (i < sz + 1 && allowSigns && !foundDigit)) {
if (chars[i] >= '0' && chars[i] <= '9') {
foundDigit = true;
allowSigns = false;
} else if (chars[i] == '.') {
if (hasDecPoint || hasExp) {
// two decimal points or dec in exponent
return false;
}
hasDecPoint = true;
} else if (chars[i] == 'e' || chars[i] == 'E') {
// we've already taken care of hex.
if (hasExp) {
// two E's
return false;
}
if (!foundDigit) {
return false;
}
hasExp = true;
allowSigns = true;
} else if (chars[i] == '+' || chars[i] == '-') {
if (!allowSigns) {
return false;
}
allowSigns = false;
foundDigit = false; // we need a digit after the E
} else {
return false;
}
i++;
}
if (i < chars.length) {
if (chars[i] >= '0' && chars[i] <= '9') {
// no type qualifier, OK
return true;
}
if (chars[i] == 'e' || chars[i] == 'E') {
// can't have an E at the last byte
return false;
}
if (!allowSigns
&& (chars[i] == 'd'
|| chars[i] == 'D'
|| chars[i] == 'f'
|| chars[i] == 'F')) {
return foundDigit;
}
if (chars[i] == 'l'
|| chars[i] == 'L') {
// not allowing L with an exponent
return foundDigit && !hasExp;
}
// last character is illegal
return false;
}
// allowSigns is true iff the val ends in 'E'
// found digit it to make sure weird stuff like '.' and '1E-' doesn't pass
return !allowSigns && foundDigit;
}
}