public final class

Long

extends Number
implements Comparable<T>
java.lang.Object
   ↳ java.lang.Number
     ↳ java.lang.Long

Class Overview

The wrapper for the primitive type long.

Implementation note: The "bit twiddling" methods in this class use techniques described in Henry S. Warren, Jr.'s Hacker's Delight, (Addison Wesley, 2002) and Sean Anderson's Bit Twiddling Hacks.

See Also

Summary

Constants
long MAX_VALUE Constant for the maximum long value, 263-1.
long MIN_VALUE Constant for the minimum long value, -263.
int SIZE Constant for the number of bits needed to represent a long in two's complement form.
Class<Long> TYPE The Class object that represents the primitive type long.
Public Constructors
Long(long value)
Constructs a new Long with the specified primitive long value.
Long(String string)
Constructs a new Long from the specified string.
Public Methods
static int bitCount(long v)
Counts the number of 1 bits in the specified long value; this is also referred to as population count.
byte byteValue()
Returns this object's value as a byte.
int compareTo(Long object)
Compares this object to the specified long object to determine their relative order.
static Long decode(String string)
Parses the specified string and returns a Long instance if the string can be decoded into a long value.
double doubleValue()
Returns this object's value as a double.
boolean equals(Object o)
Compares this instance with the specified object and indicates if they are equal.
float floatValue()
Returns this object's value as a float.
static Long getLong(String string, Long defaultValue)
Returns the Long value of the system property identified by string.
static Long getLong(String string, long defaultValue)
Returns the Long value of the system property identified by string.
static Long getLong(String string)
Returns the Long value of the system property identified by string.
int hashCode()
Returns an integer hash code for this object.
static long highestOneBit(long v)
Determines the highest (leftmost) bit of the specified long value that is 1 and returns the bit mask value for that bit.
int intValue()
Returns this object's value as an int.
long longValue()
Gets the primitive value of this long.
static long lowestOneBit(long v)
Determines the lowest (rightmost) bit of the specified long value that is 1 and returns the bit mask value for that bit.
static int numberOfLeadingZeros(long v)
Determines the number of leading zeros in the specified long value prior to the highest one bit.
static int numberOfTrailingZeros(long v)
Determines the number of trailing zeros in the specified long value after the lowest one bit.
static long parseLong(String string, int radix)
Parses the specified string as a signed long value using the specified radix.
static long parseLong(String string)
Parses the specified string as a signed decimal long value.
static long reverse(long v)
Reverses the order of the bits of the specified long value.
static long reverseBytes(long v)
Reverses the order of the bytes of the specified long value.
static long rotateLeft(long v, int distance)
Rotates the bits of the specified long value to the left by the specified number of bits.
static long rotateRight(long v, int distance)
Rotates the bits of the specified long value to the right by the specified number of bits.
short shortValue()
Returns this object's value as a short.
static int signum(long v)
Returns the value of the signum function for the specified long value.
static String toBinaryString(long v)
Converts the specified long value into its binary string representation.
static String toHexString(long v)
Converts the specified long value into its hexadecimal string representation.
static String toOctalString(long v)
Converts the specified long value into its octal string representation.
String toString()
Returns a string containing a concise, human-readable description of this object.
static String toString(long n)
Converts the specified long value into its decimal string representation.
static String toString(long v, int radix)
Converts the specified signed long value into a string representation based on the specified radix.
static Long valueOf(String string, int radix)
Parses the specified string as a signed long value using the specified radix.
static Long valueOf(long v)
Returns a Long instance for the specified long value.
static Long valueOf(String string)
Parses the specified string as a signed decimal long value.
[Expand]
Inherited Methods
From class java.lang.Number
From class java.lang.Object
From interface java.lang.Comparable

Constants

public static final long MAX_VALUE

Since: API Level 1

Constant for the maximum long value, 263-1.

Constant Value: 9223372036854775807 (0x7fffffffffffffff)

public static final long MIN_VALUE

Since: API Level 1

Constant for the minimum long value, -263.

Constant Value: -9223372036854775808 (0x8000000000000000)

public static final int SIZE

Since: API Level 1

Constant for the number of bits needed to represent a long in two's complement form.

Constant Value: 64 (0x00000040)

public static final Class<Long> TYPE

Since: API Level 1

The Class object that represents the primitive type long.

Public Constructors

public Long (long value)

Since: API Level 1

Constructs a new Long with the specified primitive long value.

Parameters
value the primitive long value to store in the new instance.

public Long (String string)

Since: API Level 1

Constructs a new Long from the specified string.

Parameters
string the string representation of a long value.
Throws
NumberFormatException if string can not be decoded into a long value.
See Also

Public Methods

public static int bitCount (long v)

Since: API Level 1

Counts the number of 1 bits in the specified long value; this is also referred to as population count.

Parameters
v the long to examine.
Returns
  • the number of 1 bits in v.

public byte byteValue ()

Since: API Level 1

Returns this object's value as a byte. Might involve rounding and/or truncating the value, so it fits into a byte.

Returns
  • the primitive byte value of this object.

public int compareTo (Long object)

Since: API Level 1

Compares this object to the specified long object to determine their relative order.

Parameters
object the long object to compare this object to.
Returns
  • a negative value if the value of this long is less than the value of object; 0 if the value of this long and the value of object are equal; a positive value if the value of this long is greater than the value of object.
See Also

public static Long decode (String string)

Since: API Level 1

Parses the specified string and returns a Long instance if the string can be decoded into a long value. The string may be an optional minus sign "-" followed by a hexadecimal ("0x..." or "#..."), octal ("0..."), or decimal ("...") representation of a long.

Parameters
string a string representation of a long value.
Returns
  • a Long containing the value represented by string.
Throws
NumberFormatException if string can not be parsed as a long value.

public double doubleValue ()

Since: API Level 1

Returns this object's value as a double. Might involve rounding.

Returns
  • the primitive double value of this object.

public boolean equals (Object o)

Since: API Level 1

Compares this instance with the specified object and indicates if they are equal. In order to be equal, o must be an instance of Long and have the same long value as this object.

Parameters
o the object to compare this long with.
Returns
  • true if the specified object is equal to this Long; false otherwise.

public float floatValue ()

Since: API Level 1

Returns this object's value as a float. Might involve rounding.

Returns
  • the primitive float value of this object.

public static Long getLong (String string, Long defaultValue)

Since: API Level 1

Returns the Long value of the system property identified by string. Returns the specified default value if string is null or empty, if the property can not be found or if its value can not be parsed as a long.

Parameters
string the name of the requested system property.
defaultValue the default value that is returned if there is no long system property with the requested name.
Returns
  • the requested property's value as a Long or the default value.

public static Long getLong (String string, long defaultValue)

Since: API Level 1

Returns the Long value of the system property identified by string. Returns the specified default value if string is null or empty, if the property can not be found or if its value can not be parsed as a long.

Parameters
string the name of the requested system property.
defaultValue the default value that is returned if there is no long system property with the requested name.
Returns
  • the requested property's value as a Long or the default value.

public static Long getLong (String string)

Since: API Level 1

Returns the Long value of the system property identified by string. Returns null if string is null or empty, if the property can not be found or if its value can not be parsed as a long.

Parameters
string the name of the requested system property.
Returns
  • the requested property's value as a Long or null.

public int hashCode ()

Since: API Level 1

Returns an integer hash code for this object. By contract, any two objects for which equals(Object) returns true must return the same hash code value. This means that subclasses of Object usually override both methods or neither method.

Note that hash values must not change over time unless information used in equals comparisons also changes.

See Writing a correct hashCode method if you intend implementing your own hashCode method.

Returns
  • this object's hash code.

public static long highestOneBit (long v)

Since: API Level 1

Determines the highest (leftmost) bit of the specified long value that is 1 and returns the bit mask value for that bit. This is also referred to as the Most Significant 1 Bit. Returns zero if the specified long is zero.

Parameters
v the long to examine.
Returns
  • the bit mask indicating the highest 1 bit in v.

public int intValue ()

Since: API Level 1

Returns this object's value as an int. Might involve rounding and/or truncating the value, so it fits into an int.

Returns
  • the primitive int value of this object.

public long longValue ()

Since: API Level 1

Gets the primitive value of this long.

Returns
  • this object's primitive value.

public static long lowestOneBit (long v)

Since: API Level 1

Determines the lowest (rightmost) bit of the specified long value that is 1 and returns the bit mask value for that bit. This is also referred to as the Least Significant 1 Bit. Returns zero if the specified long is zero.

Parameters
v the long to examine.
Returns
  • the bit mask indicating the lowest 1 bit in v.

public static int numberOfLeadingZeros (long v)

Since: API Level 1

Determines the number of leading zeros in the specified long value prior to the highest one bit.

Parameters
v the long to examine.
Returns
  • the number of leading zeros in v.

public static int numberOfTrailingZeros (long v)

Since: API Level 1

Determines the number of trailing zeros in the specified long value after the lowest one bit.

Parameters
v the long to examine.
Returns
  • the number of trailing zeros in v.

public static long parseLong (String string, int radix)

Since: API Level 1

Parses the specified string as a signed long value using the specified radix. The ASCII character - ('-') is recognized as the minus sign.

Parameters
string the string representation of a long value.
radix the radix to use when parsing.
Returns
  • the primitive long value represented by string using radix.
Throws
NumberFormatException if string is null or has a length of zero, radix < Character.MIN_RADIX, radix > Character.MAX_RADIX, or if string can not be parsed as a long value.

public static long parseLong (String string)

Since: API Level 1

Parses the specified string as a signed decimal long value. The ASCII character - ('-') is recognized as the minus sign.

Parameters
string the string representation of a long value.
Returns
  • the primitive long value represented by string.
Throws
NumberFormatException if string is null, has a length of zero or can not be parsed as a long value.

public static long reverse (long v)

Since: API Level 1

Reverses the order of the bits of the specified long value.

Parameters
v the long value for which to reverse the bit order.
Returns
  • the reversed value.

public static long reverseBytes (long v)

Since: API Level 1

Reverses the order of the bytes of the specified long value.

Parameters
v the long value for which to reverse the byte order.
Returns
  • the reversed value.

public static long rotateLeft (long v, int distance)

Since: API Level 1

Rotates the bits of the specified long value to the left by the specified number of bits.

Parameters
v the long value to rotate left.
distance the number of bits to rotate.
Returns
  • the rotated value.

public static long rotateRight (long v, int distance)

Since: API Level 1

Rotates the bits of the specified long value to the right by the specified number of bits.

Parameters
v the long value to rotate right.
distance the number of bits to rotate.
Returns
  • the rotated value.

public short shortValue ()

Since: API Level 1

Returns this object's value as a short. Might involve rounding and/or truncating the value, so it fits into a short.

Returns
  • the primitive short value of this object.

public static int signum (long v)

Since: API Level 1

Returns the value of the signum function for the specified long value.

Parameters
v the long value to check.
Returns
  • -1 if v is negative, 1 if v is positive, 0 if v is zero.

public static String toBinaryString (long v)

Since: API Level 1

Converts the specified long value into its binary string representation. The returned string is a concatenation of '0' and '1' characters.

Parameters
v the long value to convert.
Returns
  • the binary string representation of v.

public static String toHexString (long v)

Since: API Level 1

Converts the specified long value into its hexadecimal string representation. The returned string is a concatenation of characters from '0' to '9' and 'a' to 'f'.

Parameters
v the long value to convert.
Returns
  • the hexadecimal string representation of l.

public static String toOctalString (long v)

Since: API Level 1

Converts the specified long value into its octal string representation. The returned string is a concatenation of characters from '0' to '7'.

Parameters
v the long value to convert.
Returns
  • the octal string representation of l.

public String toString ()

Since: API Level 1

Returns a string containing a concise, human-readable description of this object. Subclasses are encouraged to override this method and provide an implementation that takes into account the object's type and data. The default implementation is equivalent to the following expression: 

   getClass().getName() + '@' + Integer.toHexString(hashCode())

See Writing a useful toString method if you intend implementing your own toString method.

Returns
  • a printable representation of this object.

public static String toString (long n)

Since: API Level 1

Converts the specified long value into its decimal string representation. The returned string is a concatenation of a minus sign if the number is negative and characters from '0' to '9'.

Parameters
n the long to convert.
Returns
  • the decimal string representation of l.

public static String toString (long v, int radix)

Since: API Level 1

Converts the specified signed long value into a string representation based on the specified radix. The returned string is a concatenation of a minus sign if the number is negative and characters from '0' to '9' and 'a' to 'z', depending on the radix. If radix is not in the interval defined by Character.MIN_RADIX and Character.MAX_RADIX then 10 is used as the base for the conversion.

This method treats its argument as signed. If you want to convert an unsigned value to one of the common non-decimal bases, you may find toBinaryString(long), #toHexString, or toOctalString(long) more convenient.

Parameters
v the signed long to convert.
radix the base to use for the conversion.
Returns
  • the string representation of v.

public static Long valueOf (String string, int radix)

Since: API Level 1

Parses the specified string as a signed long value using the specified radix.

Parameters
string the string representation of a long value.
radix the radix to use when parsing.
Returns
  • a Long instance containing the long value represented by string using radix.
Throws
NumberFormatException if string is null or has a length of zero, radix < Character.MIN_RADIX, radix > Character.MAX_RADIX, or if string can not be parsed as a long value.
See Also

public static Long valueOf (long v)

Since: API Level 1

Returns a Long instance for the specified long value.

If it is not necessary to get a new Long instance, it is recommended to use this method instead of the constructor, since it maintains a cache of instances which may result in better performance.

Parameters
v the long value to store in the instance.
Returns
  • a Long instance containing v.

public static Long valueOf (String string)

Since: API Level 1

Parses the specified string as a signed decimal long value.

Parameters
string the string representation of a long value.
Returns
  • a Long instance containing the long value represented by string.
Throws
NumberFormatException if string is null, has a length of zero or can not be parsed as a long value.
See Also