java.lang.Object
java.lang.Number
java.lang.Long
public final class Long
The Long class wraps a value of the primitive type long in an object. An object of type Long contains a single field whose type is long.
In addition, this class provides several methods for converting a long to a String and a String to a long, as well as other constants and methods useful when dealing with a long.
Implementation note: The implementations of the "bit twiddling" methods (such as highestOneBit and numberOfTrailingZeros) are based on material from Henry S. Warren, Jr.'s Hacker's Delight, (Addison Wesley, 2002).
static long MAX_VALUE
long can have, 263-1. static long MIN_VALUE
long can have, -263. static int SIZE
static Class<Long> TYPE
Class instance representing the primitive type long. Constructor Summary Long(long value)
Long object that represents the specified long argument. Long(String s)
Long object that represents the long value indicated by the String parameter. Method Summary static int bitCount(long i)
byte byteValue()
Long as a byte. int compareTo(Long anotherLong)
Long objects numerically. static Long decode(String nm)
String into a Long. double doubleValue()
Long as a double. boolean equals(Object obj)
float floatValue()
Long as a float. static Long getLong(String nm)
long value of the system property with the specified name. static Long getLong(String nm, long val)
long value of the system property with the specified name. static Long getLong(String nm, Long val)
long value of the system property with the specified name. int hashCode()
Long. static long highestOneBit(long i)
int intValue()
Long as an int. long longValue()
Long as a long value. static long lowestOneBit(long i)
static int numberOfLeadingZeros(long i)
static int numberOfTrailingZeros(long i)
static long parseLong(String s)
long. static long parseLong(String s, int radix)
long in the radix specified by the second argument. static long reverse(long i)
static long reverseBytes(long i)
static long rotateLeft(long i, int distance)
static long rotateRight(long i, int distance)
short shortValue()
Long as a short. static int signum(long i)
static String toBinaryString(long i)
long argument as an unsigned integer in base 2. static String toHexString(long i)
long argument as an unsigned integer in base 16. static String toOctalString(long i)
long argument as an unsigned integer in base 8. String toString()
String object representing this Long's value. static String toString(long i)
String object representing the specified long. static String toString(long i, int radix)
static Long valueOf(long l)
static Long valueOf(String s)
Long object holding the value of the specified String. static Long valueOf(String s, int radix)
Long object holding the value extracted from the specified String when parsed with the radix given by the second argument. MIN_VALUE
public static final long MIN_VALUE
long can have, -263.
public static final long MAX_VALUE
long can have, 263-1.
public static final Class<Long> TYPE
Class instance representing the primitive type long.
public static final int SIZE
public Long(long value)
Long object that represents the specified long argument.
value - the value to be represented by the Long object.
public Long(String s)
throws NumberFormatException
Long object that represents the long value indicated by the String parameter. The string is converted to a long value in exactly the manner used by the parseLong method for radix 10.
s - the String to be converted to a Long.
NumberFormatException - if the String does not contain a parsable long.
parseLong(java.lang.String, int)
public static String toString(long i,
int radix)
If the radix is smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX, then the radix 10 is used instead.
If the first argument is negative, the first element of the result is the ASCII minus sign '-' ('\u002d'). If the first argument is not negative, no sign character appears in the result.
The remaining characters of the result represent the magnitude of the first argument. If the magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the magnitude will not be the zero character. The following ASCII characters are used as digits:
These are0123456789abcdefghijklmnopqrstuvwxyz
'\u0030' through '\u0039' and '\u0061' through '\u007a'. If radix is N, then the first N of these characters are used as radix-N digits in the order shown. Thus, the digits for hexadecimal (radix 16) are 0123456789abcdef. If uppercase letters are desired, the String.toUpperCase() method may be called on the result:
Long.toString(n, 16).toUpperCase()
i - a longto be converted to a string.
radix - the radix to use in the string representation.
Character.MAX_RADIX, Character.MIN_RADIX
public static String toHexString(long i)
long argument as an unsigned integer in base 16.
The unsigned long value is the argument plus 264 if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in hexadecimal (base 16) with no extra leading 0s. If the unsigned magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The following characters are used as hexadecimal digits:
These are the characters0123456789abcdef
'\u0030' through '\u0039' and '\u0061' through '\u0066'. If uppercase letters are desired, the String.toUpperCase() method may be called on the result:
Long.toHexString(n).toUpperCase()
i - a long to be converted to a string.
long value represented by the argument in hexadecimal (base 16).
public static String toOctalString(long i)
long argument as an unsigned integer in base 8.
The unsigned long value is the argument plus 264 if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in octal (base 8) with no extra leading 0s.
If the unsigned magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The following characters are used as octal digits:
These are the characters01234567
'\u0030' through '\u0037'.
i - a long to be converted to a string.
long value represented by the argument in octal (base 8).
public static String toBinaryString(long i)
long argument as an unsigned integer in base 2.
The unsigned long value is the argument plus 264 if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in binary (base 2) with no extra leading 0s. If the unsigned magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The characters '0' ('\u0030') and '1' ('\u0031') are used as binary digits.
i - a long to be converted to a string.
long value represented by the argument in binary (base 2).
public static String toString(long i)
String object representing the specified long. The argument is converted to signed decimal representation and returned as a string, exactly as if the argument and the radix 10 were given as arguments to the toString(long, int) method.
i - a long to be converted.
public static long parseLong(String s,
int radix)
throws NumberFormatException
long in the radix specified by the second argument. The characters in the string must all be digits of the specified radix (as determined by whether Character.digit(char, int) returns a nonnegative value), except that the first character may be an ASCII minus sign '-' ('\u002D') to indicate a negative value. The resulting long value is returned.
Note that neither the character L ('\u004C') nor l ('\u006C') is permitted to appear at the end of the string as a type indicator, as would be permitted in Java programming language source code - except that either L or l may appear as a digit for a radix greater than 22.
An exception of type NumberFormatException is thrown if any of the following situations occurs:
null or is a string of length zero.radix is either smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX.'-' ('\u002d') provided that the string is longer than length 1.long.Examples:
parseLong("0", 10) returns 0L
parseLong("473", 10) returns 473L
parseLong("-0", 10) returns 0L
parseLong("-FF", 16) returns -255L
parseLong("1100110", 2) returns 102L
parseLong("99", 8) throws a NumberFormatException
parseLong("Hazelnut", 10) throws a NumberFormatException
parseLong("Hazelnut", 36) returns 1356099454469L
s - the String containing the long representation to be parsed.
radix - the radix to be used while parsing s.
long represented by the string argument in the specified radix.
NumberFormatException - if the string does not contain a parsable long.
public static long parseLong(String s)
throws NumberFormatException
long. The characters in the string must all be decimal digits, except that the first character may be an ASCII minus sign '-' (\u002D') to indicate a negative value. The resulting long value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseLong(java.lang.String, int) method.
Note that neither the character L ('\u004C') nor l ('\u006C') is permitted to appear at the end of the string as a type indicator, as would be permitted in Java programming language source code.
s - a String containing the long representation to be parsed
long represented by the argument in decimal.
NumberFormatException - if the string does not contain a parsable long.
public static Long valueOf(String s,
int radix)
throws NumberFormatException
Long object holding the value extracted from the specified String when parsed with the radix given by the second argument. The first argument is interpreted as representing a signed long in the radix specified by the second argument, exactly as if the arguments were given to the parseLong(java.lang.String, int) method. The result is a Long object that represents the long value specified by the string.
In other words, this method returns a Long object equal to the value of:
new Long(Long.parseLong(s, radix))
s - the string to be parsed
radix - the radix to be used in interpreting s
Long object holding the value represented by the string argument in the specified radix.
NumberFormatException - If the String does not contain a parsable long.
public static Long valueOf(String s)
throws NumberFormatException
Long object holding the value of the specified String. The argument is interpreted as representing a signed decimal long, exactly as if the argument were given to the parseLong(java.lang.String) method. The result is a Long object that represents the integer value specified by the string.
In other words, this method returns a Long object equal to the value of:
new Long(Long.parseLong(s))
s - the string to be parsed.
Long object holding the value represented by the string argument.
NumberFormatException - If the string cannot be parsed as a long.
public static Long valueOf(long l)
Long(long), as this method is likely to yield significantly better space and time performance by caching frequently requested values.
l - a long value.
public static Long decode(String nm)
throws NumberFormatException
String into a Long. Accepts decimal, hexadecimal, and octal numbers given by the following grammar:
DecimalNumeral, HexDigits, and OctalDigits are defined in §3.10.1 of the Java Language Specification.
- DecodableString:
- Signopt DecimalNumeral
- Signopt
0xHexDigits- Signopt
0XHexDigits- Signopt
#HexDigits- Signopt
0OctalDigits- Sign:
-
The sequence of characters following an (optional) negative sign and/or radix specifier ("0x", "0X", "#", or leading zero) is parsed as by the Long.parseLong method with the indicated radix (10, 16, or 8). This sequence of characters must represent a positive value or a NumberFormatException will be thrown. The result is negated if first character of the specified String is the minus sign. No whitespace characters are permitted in the String.
nm - the String to decode.
Long object holding the long value represented by nm
NumberFormatException - if the String does not contain a parsable long.
parseLong(String, int)
public byte byteValue()
Long as a byte.
byteValue in class Number
byte.
public short shortValue()
Long as a short.
shortValue in class Number
short.
public int intValue()
Long as an int.
intValue in class Number
int.
public long longValue()
Long as a long value.
longValue in class Number
long.
public float floatValue()
Long as a float.
floatValue in class Number
float.
public double doubleValue()
Long as a double.
doubleValue in class Number
double.
public String toString()
String object representing this Long's value. The value is converted to signed decimal representation and returned as a string, exactly as if the long value were given as an argument to the toString(long) method.
toString in class Object
public int hashCode()
Long. The result is the exclusive OR of the two halves of the primitive long value held by this Long object. That is, the hashcode is the value of the expression:
(int)(this.longValue()^(this.longValue()>>>32))
hashCode in class Object
Object.equals(java.lang.Object), Hashtable
public boolean equals(Object obj)
true if and only if the argument is not null and is a Long object that contains the same long value as this object.
equals in class Object
obj - the object to compare with.
true if the objects are the same; false otherwise.
Object.hashCode(), Hashtable
public static Long getLong(String nm)
long value of the system property with the specified name.
The first argument is treated as the name of a system property. System properties are accessible through the System.getProperty(java.lang.String) method. The string value of this property is then interpreted as a long value and a Long object representing this value is returned. Details of possible numeric formats can be found with the definition of getProperty.
If there is no property with the specified name, if the specified name is empty or null, or if the property does not have the correct numeric format, then null is returned.
In other words, this method returns a Long object equal to the value of:
getLong(nm, null)
nm - property name.
Long value of the property.
System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String)
public static Long getLong(String nm,
long val)
long value of the system property with the specified name.
The first argument is treated as the name of a system property. System properties are accessible through the System.getProperty(java.lang.String) method. The string value of this property is then interpreted as a long value and a Long object representing this value is returned. Details of possible numeric formats can be found with the definition of getProperty.
The second argument is the default value. A Long object that represents the value of the second argument is returned if there is no property of the specified name, if the property does not have the correct numeric format, or if the specified name is empty or null.
In other words, this method returns a Long object equal to the value of:
getLong(nm, new Long(val))
but in practice it may be implemented in a manner such as:
to avoid the unnecessary allocation of aLong result = getLong(nm, null); return (result == null) ? new Long(val) : result;
Long object when the default value is not needed.
nm - property name.
val - default value.
Long value of the property.
System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String)
public static Long getLong(String nm,
Long val)
long value of the system property with the specified name. The first argument is treated as the name of a system property. System properties are accessible through the System.getProperty(java.lang.String) method. The string value of this property is then interpreted as a long value, as per the Long.decode method, and a Long object representing this value is returned.
0x or the ASCII character #, not followed by a minus sign, then the rest of it is parsed as a hexadecimal integer exactly as for the method valueOf(java.lang.String, int) with radix 16.0 followed by another character, it is parsed as an octal integer exactly as by the method valueOf(java.lang.String, int) with radix 8.valueOf(java.lang.String, int) with radix 10.Note that, in every case, neither L ('\u004C') nor l ('\u006C') is permitted to appear at the end of the property value as a type indicator, as would be permitted in Java programming language source code.
The second argument is the default value. The default value is returned if there is no property of the specified name, if the property does not have the correct numeric format, or if the specified name is empty or null.
nm - property name.
val - default value.
Long value of the property.
System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String), decode(java.lang.String)
public int compareTo(Long anotherLong)
Long objects numerically.
compareTo in interface Comparable<Long>
anotherLong - the Long to be compared.
0 if this Long is equal to the argument Long; a value less than 0 if this Long is numerically less than the argument Long; and a value greater than 0 if this Long is numerically greater than the argument Long (signed comparison).
public static long highestOneBit(long i)
public static long lowestOneBit(long i)
public static int numberOfLeadingZeros(long i)
Note that this method is closely related to the logarithm base 2. For all positive long values x:
public static int numberOfTrailingZeros(long i)
public static int bitCount(long i)
public static long rotateLeft(long i,
int distance)
Note that left rotation with a negative distance is equivalent to right rotation: rotateLeft(val, -distance) == rotateRight(val, distance). Note also that rotation by any multiple of 64 is a no-op, so all but the last six bits of the rotation distance can be ignored, even if the distance is negative: rotateLeft(val, distance) == rotateLeft(val, distance & 0x3F).
public static long rotateRight(long i,
int distance)
Note that right rotation with a negative distance is equivalent to left rotation: rotateRight(val, -distance) == rotateLeft(val, distance). Note also that rotation by any multiple of 64 is a no-op, so all but the last six bits of the rotation distance can be ignored, even if the distance is negative: rotateRight(val, distance) == rotateRight(val, distance & 0x3F).
public static long reverse(long i)
public static int signum(long i)
public static long reverseBytes(long i)
Copyright © 2004, 2010 Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
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