java.lang
Class Long

java.lang.Object
  java.lang.Long

public final class Long
extends Object

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.

Since:

JDK1.0

Version:

1.51, 12/04/99 (CLDC 1.0, Spring 2000)

Author:

Lee Boynton, Arthur van Hoff

Field Summary

static long	MAX_VALUE The largest value of type long.
static long	MIN_VALUE The smallest value of type long.

Constructor Summary

Long(long value)
Constructs a newly allocated Long object that represents the primitive long argument.

Method Summary

double	doubleValue() Returns the value of this Long as a double.
boolean	equals(Object obj) Compares this object against the specified object.
float	floatValue() Returns the value of this Long as a float.
int	hashCode() Computes a hashcode for this Long.
long	longValue() Returns the value of this Long as a long value.
static long	parseLong(String s) Parses the string argument as a signed decimal long.
static long	parseLong(String s, int radix) Parses the string argument as a signed long in the radix specified by the second argument.
String	toString() Returns a String object representing this Long's value.
static String	toString(long i) Returns a new String object representing the specified integer.
static String	toString(long i, int radix) Creates a string representation of the first argument in the radix specified by the second argument.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

MAX_VALUE

public static final long MAX_VALUE

The largest value of type long.

See Also:

Constant Field Values

MIN_VALUE

public static final long MIN_VALUE

The smallest value of type long.

See Also:

Constant Field Values

Constructor Detail

Long

public Long(long value)

Constructs a newly allocated Long object that represents the primitive long argument.

Parameters:

value - the value to be represented by the Long object.

Method Detail

doubleValue

public double doubleValue()

Returns the value of this Long as a double.

equals

public boolean equals(Object obj)

Compares this object against 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.

Overrides:

equals in class Object

Parameters:

obj - the object to compare with.

Returns:

true if the objects are the same; false otherwise.

See Also:

Boolean.hashCode(), Hashtable

floatValue

public float floatValue()

Returns the value of this Long as a float.

hashCode

public int hashCode()

Computes a hashcode for this Long. The result is the exclusive OR of the two halves of the primitive long value represented by this Long object. That is, the hashcode is the value of the expression:

 (int)(this.longValue()^(this.longValue()>>>32))
 

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), Hashtable

longValue

public long longValue()

Returns the value of this Long as a long value.

Returns:

the long value represented by this object.

parseLong

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. The resulting long value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseLong(String, int) method that takes two arguments.

Note that neither L nor l is permitted to appear at the end of the string as a type indicator, as would be permitted in Java programming language source code.

Parameters:

s - a string.

Returns:

the long represented by the argument in decimal.

Throws:

NumberFormatException - if the string does not contain a parsable long.

parseLong

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 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 L nor l 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:

• The first argument is null or is a string of length zero.
• The radix is either smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX.
• The first character of the string is not a digit of the specified radix and is not a minus sign '-' ('\u002d').
• The first character of the string is a minus sign and the string is of length 1.
• Any character of the string after the first is not a digit of the specified radix.
• The integer value represented by the string cannot be represented as a value of type 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
 

Parameters:

s - the String containing the long.

radix - the radix to be used.

Returns:

the long represented by the string argument in the specified radix.

Throws:

NumberFormatException - if the string does not contain a parsable integer.

toString

public String toString()

Returns a String object representing this Long's value. The long integer value represented by this Long object 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 that takes one argument.

Overrides:

toString in class Object

Returns:

a string representation of this object in base 10.

toString

public static String toString(long i)

Returns a new String object representing the specified integer. 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 that takes two arguments.

Parameters:

i - a long to be converted.

Returns:

a string representation of the argument in base 10.

toString

public static String toString(long i,
                              int radix)

Creates 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:

   0123456789abcdefghijklmnopqrstuvwxyz
 

These are '\u0030' through '\u0039' and '\u0061' through '\u007a'. If the 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.
 

Parameters:

i - a long.

radix - the radix.

Returns:

a string representation of the argument in the specified radix.

See Also:

Character.MAX_RADIX, Character.MIN_RADIX