public final class Long extends Number implements Comparable<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).
@Native public static final long MIN_VALUE
A constant holding the minimum value a long can have, -263.
@Native public static final long MAX_VALUE
A constant holding the maximum value a long can have, 263-1.
public static final Class<Long> TYPE
The Class instance representing the primitive type long.
@Native public static final int SIZE
The number of bits used to represent a long value in two's complement binary form.
public static final int BYTES
The number of bytes used to represent a long value in two's complement binary form.
public Long(long value)
Constructs a newly allocated Long object that represents the specified long argument.
value - the value to be represented by the Long object.public Long(String s)
throws NumberFormatException Constructs a newly allocated 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) Returns a string representation of the first argument in the radix specified by the second argument.
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:
0123456789abcdefghijklmnopqrstuvwxyzThese are
'\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 long to be converted to a string.radix - the radix to use in the string representation.Character.MAX_RADIX, Character.MIN_RADIX
public static String toUnsignedString(long i,
int radix) Returns a string representation of the first argument as an unsigned integer value in the radix specified by the second argument.
If the radix is smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX, then the radix 10 is used instead.
Note that since the first argument is treated as an unsigned value, no leading sign character is printed.
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 behavior of radixes and the characters used as digits are the same as toString.
i - an integer to be converted to an unsigned string.radix - the radix to use in the string representation.toString(long, int)public static String toHexString(long i)
Returns a string representation of the 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.
The value of the argument can be recovered from the returned string s by calling Long.parseUnsignedLong(s,
16).
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:
0123456789abcdefThese are the characters
'\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).parseUnsignedLong(String, int), toUnsignedString(long, int)
public static String toOctalString(long i)
Returns a string representation of the 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.
The value of the argument can be recovered from the returned string s by calling Long.parseUnsignedLong(s,
8).
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:
01234567These are the characters
'\u0030' through '\u0037'.i - a long to be converted to a string.long value represented by the argument in octal (base 8).parseUnsignedLong(String, int), toUnsignedString(long, int)
public static String toBinaryString(long i)
Returns a string representation of the 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.
The value of the argument can be recovered from the returned string s by calling Long.parseUnsignedLong(s,
2).
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).parseUnsignedLong(String, int), toUnsignedString(long, int)
public static String toString(long i)
Returns a 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 String toUnsignedString(long i)
Returns a string representation of the argument as an unsigned decimal value. The argument is converted to unsigned decimal representation and returned as a string exactly as if the argument and radix 10 were given as arguments to the toUnsignedString(long,
int) method.
i - an integer to be converted to an unsigned string.toUnsignedString(long, int)public static long parseLong(String s,
int radix)
throws NumberFormatException Parses the string argument as a signed 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 or an ASCII plus sign '+' ('\u002B') to indicate a positive 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 or equal to 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') or plus sign '+' ('\u002B') provided that the string is longer than length 1. long. Examples:
parseLong("0", 10) returns 0L
parseLong("473", 10) returns 473L
parseLong("+42", 10) returns 42L
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 Parses the string argument as a signed decimal 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 or an ASCII plus sign '+' ('\u002B') to indicate a positive 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 parsedlong represented by the argument in decimal.NumberFormatException - if the string does not contain a parsable long.public static long parseUnsignedLong(String s,
int radix)
throws NumberFormatException Parses the string argument as an unsigned long in the radix specified by the second argument. An unsigned integer maps the values usually associated with negative numbers to positive numbers larger than MAX_VALUE. 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 plus sign '+' ('\u002B'). The resulting integer value is returned.
An exception of type NumberFormatException is thrown if any of the following situations occurs:
null or is a string of length zero. Character.MIN_RADIX or larger than Character.MAX_RADIX. '+' ('\u002B') provided that the string is longer than length 1. long, 264-1. s - the String containing the unsigned integer representation to be parsedradix - 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 parseUnsignedLong(String s)
throws NumberFormatException Parses the string argument as an unsigned decimal long. The characters in the string must all be decimal digits, except that the first character may be an an ASCII plus sign '+' ('\u002B'). The resulting integer value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseUnsignedLong(java.lang.String, int) method.
s - a String containing the unsigned long representation to be parsedlong value represented by the decimal string argumentNumberFormatException - if the string does not contain a parsable unsigned integer.public static Long valueOf(String s,
int radix)
throws NumberFormatException Returns a 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 parsedradix - 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 Returns a 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)
Returns a Long instance representing the specified long value. If a new Long instance is not required, this method should generally be used in preference to the constructor Long(long), as this method is likely to yield significantly better space and time performance by caching frequently requested values. Note that unlike the corresponding method in the Integer class, this method is not required to cache values within a particular range.
l - a long value.Long instance representing l.public static Long decode(String nm)
throws NumberFormatException Decodes a String into a Long. Accepts decimal, hexadecimal, and octal numbers given by the following grammar:
0x HexDigits 0X HexDigits # HexDigits 0 OctalDigits - + The sequence of characters following an optional 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()
Returns the value of this Long as a byte after a narrowing primitive conversion.
byteValue in class Number
byte.public short shortValue()
Returns the value of this Long as a short after a narrowing primitive conversion.
shortValue in class Number
short.public int intValue()
Returns the value of this Long as an int after a narrowing primitive conversion.
intValue in class Number
int.public long longValue()
Returns the value of this Long as a long value.
longValue in class Number
long.public float floatValue()
Returns the value of this Long as a float after a widening primitive conversion.
floatValue in class Number
float.public double doubleValue()
Returns the value of this Long as a double after a widening primitive conversion.
doubleValue in class Number
double.public String toString()
Returns a 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()
Returns a hash code for this 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), System.identityHashCode(java.lang.Object)
public static int hashCode(long value)
Returns a hash code for a long value; compatible with Long.hashCode().
value - the value to hashlong value.public boolean equals(Object obj)
Compares this object to the specified object. The result is 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(), HashMap
public static Long getLong(String nm)
Determines the 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 using the grammar supported by decode and a Long object representing this value is returned.
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.SecurityException - for the same reasons as System.getProperty
System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String)
public static Long getLong(String nm,
long val) Determines the 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 using the grammar supported by decode and a Long object representing this value is returned.
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:
Long result = getLong(nm, null); return (result == null) ? new Long(val) : result;to avoid the unnecessary allocation of a
Long object when the default value is not needed.nm - property name.val - default value.Long value of the property.SecurityException - for the same reasons as System.getProperty
System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String)
public static Long getLong(String nm,
Long val) Returns the 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 decode method, and a Long object representing this value is returned; in summary:
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.SecurityException - for the same reasons as System.getProperty
System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String)
public int compareTo(Long anotherLong)
Compares two 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 int compare(long x,
long y) Compares two long values numerically. The value returned is identical to what would be returned by:
Long.valueOf(x).compareTo(Long.valueOf(y))
x - the first long to comparey - the second long to compare0 if x == y; a value less than 0 if x < y; and a value greater than 0 if x > y
public static int compareUnsigned(long x,
long y) Compares two long values numerically treating the values as unsigned.
x - the first long to comparey - the second long to compare0 if x == y; a value less than 0 if x < y as unsigned values; and a value greater than 0 if x > y as unsigned valuespublic static long divideUnsigned(long dividend,
long divisor) Returns the unsigned quotient of dividing the first argument by the second where each argument and the result is interpreted as an unsigned value.
Note that in two's complement arithmetic, the three other basic arithmetic operations of add, subtract, and multiply are bit-wise identical if the two operands are regarded as both being signed or both being unsigned. Therefore separate addUnsigned, etc. methods are not provided.
dividend - the value to be divideddivisor - the value doing the dividingremainderUnsigned(long, long)public static long remainderUnsigned(long dividend,
long divisor) Returns the unsigned remainder from dividing the first argument by the second where each argument and the result is interpreted as an unsigned value.
dividend - the value to be divideddivisor - the value doing the dividingdivideUnsigned(long, long)public static long highestOneBit(long i)
Returns a long value with at most a single one-bit, in the position of the highest-order ("leftmost") one-bit in the specified long value. Returns zero if the specified value has no one-bits in its two's complement binary representation, that is, if it is equal to zero.
i - the value whose highest one bit is to be computedlong value with a single one-bit, in the position of the highest-order one-bit in the specified value, or zero if the specified value is itself equal to zero.public static long lowestOneBit(long i)
Returns a long value with at most a single one-bit, in the position of the lowest-order ("rightmost") one-bit in the specified long value. Returns zero if the specified value has no one-bits in its two's complement binary representation, that is, if it is equal to zero.
i - the value whose lowest one bit is to be computedlong value with a single one-bit, in the position of the lowest-order one-bit in the specified value, or zero if the specified value is itself equal to zero.public static int numberOfLeadingZeros(long i)
Returns the number of zero bits preceding the highest-order ("leftmost") one-bit in the two's complement binary representation of the specified long value. Returns 64 if the specified value has no one-bits in its two's complement representation, in other words if it is equal to zero.
Note that this method is closely related to the logarithm base 2. For all positive long values x:
63 - numberOfLeadingZeros(x) 64 - numberOfLeadingZeros(x - 1) i - the value whose number of leading zeros is to be computedlong value, or 64 if the value is equal to zero.public static int numberOfTrailingZeros(long i)
Returns the number of zero bits following the lowest-order ("rightmost") one-bit in the two's complement binary representation of the specified long value. Returns 64 if the specified value has no one-bits in its two's complement representation, in other words if it is equal to zero.
i - the value whose number of trailing zeros is to be computedlong value, or 64 if the value is equal to zero.public static int bitCount(long i)
Returns the number of one-bits in the two's complement binary representation of the specified long value. This function is sometimes referred to as the population count.
i - the value whose bits are to be countedlong value.public static long rotateLeft(long i,
int distance) Returns the value obtained by rotating the two's complement binary representation of the specified long value left by the specified number of bits. (Bits shifted out of the left hand, or high-order, side reenter on the right, or low-order.)
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).
i - the value whose bits are to be rotated leftdistance - the number of bit positions to rotate leftlong value left by the specified number of bits.public static long rotateRight(long i,
int distance) Returns the value obtained by rotating the two's complement binary representation of the specified long value right by the specified number of bits. (Bits shifted out of the right hand, or low-order, side reenter on the left, or high-order.)
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).
i - the value whose bits are to be rotated rightdistance - the number of bit positions to rotate rightlong value right by the specified number of bits.public static long reverse(long i)
Returns the value obtained by reversing the order of the bits in the two's complement binary representation of the specified long value.
i - the value to be reversedlong value.public static int signum(long i)
Returns the signum function of the specified long value. (The return value is -1 if the specified value is negative; 0 if the specified value is zero; and 1 if the specified value is positive.)
i - the value whose signum is to be computedlong value.public static long reverseBytes(long i)
Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specified long value.
i - the value whose bytes are to be reversedlong value.public static long sum(long a,
long b) Adds two long values together as per the + operator.
a - the first operandb - the second operanda and b
BinaryOperatorpublic static long max(long a,
long b) Returns the greater of two long values as if by calling Math.max.
a - the first operandb - the second operanda and b
BinaryOperatorpublic static long min(long a,
long b) Returns the smaller of two long values as if by calling Math.min.
a - the first operandb - the second operanda and b
BinaryOperator
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