java.lang
Class Long

java.lang.Object
  |
  +--java.lang.Number
        |
        +--java.lang.Long

public final class Long

extends Number

implements Comparable

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

See Also:

Serialized Form

Field Summary

static long	MAX_VALUE The largest value of type long.
static long	MIN_VALUE The smallest value of type long.
static Class	TYPE The Class object representing the primitive type long.

Constructor Summary

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

Long(String s)
Constructs a newly allocated Long object that represents the value represented by the string in decimal form.

Method Summary

byte	byteValue() Returns the value of this Long as a byte.
int	compareTo(Long anotherLong) Compares two Longs numerically.
int	compareTo(Object o) Compares this Long to another Object.
static Long	decode(String nm) Decodes a String into a Long.
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.
static Long	getLong(String nm) Determines the long value of the system property with the specified name.
static Long	getLong(String nm, long val) Determines the long value of the system property with the specified name.
static Long	getLong(String nm, Long val) Returns the long value of the system property with the specified name.
int	hashCode() Computes a hashcode for this Long.
int	intValue() Returns the value of this Long as an int.
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.
short	shortValue() Returns the value of this Long as a short.
static String	toBinaryString(long i) Creates a string representation of the long argument as an unsigned integer in base 2.
static String	toHexString(long i) Creates a string representation of the long argument as an unsigned integer in base 16.
static String	toOctalString(long i) Creates a string representation of the long argument as an unsigned integer in base 8.
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.
static Long	valueOf(String s) Returns a new long object initialized to the value of the specified String.
static Long	valueOf(String s, int radix) Returns a new long object initialized to the value of the specified String.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

MIN_VALUE

public static final long MIN_VALUE

The smallest value of type long.

MAX_VALUE

public static final long MAX_VALUE

The largest value of type long.

TYPE

public static final Class TYPE

The Class object representing the primitive type long.

Since:

JDK1.1

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.

Long

public Long(String s)
     throws NumberFormatException

Constructs a newly allocated Long object that represents the value represented by the string in decimal form. The string is converted to an long value as if by the parseLong(java.lang.String, int) method for radix 10.

Parameters:

s - the string to be converted to a Long.

Throws:

NumberFormatException - if the String does not contain a parsable long integer.

See Also:

valueOf(java.lang.String)

Method Detail

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. If uppercase letters are desired, the String.toUpperCase() method may be called on the result:

 Long.toString(n, 16).toUpperCase()
 

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

toHexString

public static String toHexString(long i)

Creates 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.

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:

 0123456789abcdef
 

These 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()
 

Parameters:

i - a long.

Returns:

the string representation of the unsigned long value represented by the argument in hexadecimal (base 16).

Since:

JDK 1.0.2

toOctalString

public static String toOctalString(long i)

Creates 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.

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:

 01234567
 

These are the characters '\u0030' through '\u0037'.

Parameters:

i - a long.

Returns:

the string representation of the unsigned long value represented by the argument in octal (base 8).

Since:

JDK 1.0.2

toBinaryString

public static String toBinaryString(long i)

Creates 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.

If the unsigned magnitude is zero, it is represented by a single zero character '0' ('&392;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.

Parameters:

i - a long.

Returns:

the string representation of the unsigned long value represented by the argument in binary (base 2).

Since:

JDK 1.0.2

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(java.lang.String, int) method that takes two arguments.

Parameters:

i - a long to be converted.

Returns:

a string representation of the argument in base 10.

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.

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.

valueOf

public static Long valueOf(String s,
                           int radix)
                    throws NumberFormatException

Returns a new long object initialized to the value of the specified String. Throws an exception if the String cannot be parsed as a long.

The first argument is interpreted as representing a signed integer in the radix specified by the second argument, exactly as if the arguments were given to the parseLong(java.lang.String, int) method that takes two arguments. 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, radix))
 

Parameters:

s - the String containing the long.

radix - the radix to be used.

Returns:

a newly constructed Long initialized to the value represented by the string argument in the specified radix.

Throws:

NumberFormatException - If the String does not contain a parsable long.

valueOf

public static Long valueOf(String s)
                    throws NumberFormatException

Returns a new long object initialized to the value of the specified String. Throws an exception if the String cannot be parsed as a long. The radix is assumed to be 10.

The argument is interpreted as representing a signed decimal integer, exactly as if the argument were given to the parseLong(java.lang.String) method that takes one argument). 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))
 

Parameters:

s - the string to be parsed.

Returns:

a newly constructed Long initialized to the value represented by the string argument.

Throws:

NumberFormatException - If the String does not contain a parsable long.

decode

public static Long decode(String nm)
                   throws NumberFormatException

Decodes a String into a Long. Accepts decimal, hexadecimal, and octal numbers, in the following formats:

     [-]    
     [-] 0x     
     [-] #      
     [-] 0    
 

The constant following an (optional) negative sign and/or "radix specifier" is parsed as by the Long.parseLong method with the specified radix (10, 8 or 16). This constant must be positive or a NumberFormatException will result. The result is made negative if first character of the specified String is the negative sign. No whitespace characters are permitted in the String.

Parameters:

nm - the String to decode.

Returns:

the Long represented by the specified string.

Throws:

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

See Also:

parseLong(String, int)

byteValue

public byte byteValue()

Returns the value of this Long as a byte.

Overrides:

byteValue in class Number

Since:

JDK1.1

shortValue

public short shortValue()

Returns the value of this Long as a short.

Overrides:

shortValue in class Number

Since:

JDK1.1

intValue

public int intValue()

Returns the value of this Long as an int.

Returns:

the long value represented by this object is converted to type int and the result of the conversion is returned.

Overrides:

intValue in class Number

longValue

public long longValue()

Returns the value of this Long as a long value.

Returns:

the long value represented by this object.

Overrides:

longValue in class Number

floatValue

public float floatValue()

Returns the value of this Long as a float.

Returns:

the long value represented by this object is converted to type float and the result of the conversion is returned.

Overrides:

floatValue in class Number

doubleValue

public double doubleValue()

Returns the value of this Long as a double.

Returns:

the long value represented by this object that is converted to type double and the result of the conversion is returned.

Overrides:

doubleValue in class Number

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.

Returns:

a string representation of this object in base 10.

Overrides:

toString in class Object

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))
 

Returns:

a hash code value for this object.

Overrides:

hashCode in class Object

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.

Parameters:

obj - the object to compare with.

Returns:

true if the objects are the same; false otherwise.

Overrides:

equals in class Object

getLong

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 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, 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)
 

Parameters:

nm - property name.

Returns:

the Long value of the property.

See Also:

System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String)

getLong

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 java.lang.System#getProperty() 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, or if the property does not have the correct numeric format, then a Long object that represents the value of the second argument is returned.

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.

Parameters:

nm - property name.

val - default value.

Returns:

the Long value of the property.

See Also:

System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String)

getLong

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 Long.decode method, and a Long object representing this value is returned.

• If the property value begins with the two ASCII characters 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.
• If the property value begins with the character 0 followed by another character, it is parsed as an octal integer exactly as for the method valueOf(java.lang.String, int) with radix 8.
• Otherwise the property value is parsed as a decimal integer exactly as for the method valueOf(java.lang.String, int) with radix 10.

  Note that, in every case, neither L nor l 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. If there is no property of the specified name, or if the property does not have the correct numeric format, then the second argument is returned.

  Parameters:

  nm - property name.

  val - default value.

  Returns:

  the Long value of the property.

  See Also:

  System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String), decode(java.lang.String)

compareTo

public int compareTo(Long anotherLong)

Compares two Longs numerically.

Parameters:

anotherLong - the Long to be compared.

Returns:

the value 0 if the argument Long is equal to this Long; a value less than 0 if this Long is numerically less than the Long argument; and a value greater than 0 if this Long is numerically greater than the Long argument (signed comparison).

Since:

JDK1.2

compareTo

public int compareTo(Object o)

Compares this Long to another Object. If the Object is a Long, this function behaves like compareTo(Long). Otherwise, it throws a ClassCastException (as Longs are comparable only to other Longs).

Specified by:

compareTo in interface Comparable

Parameters:

o - the Object to be compared.

Returns:

the value 0 if the argument is a Long numerically equal to this Long; a value less than 0 if the argument is a Long numerically greater than this Long; and a value greater than 0 if the argument is a Long numerically less than this Long.

Throws:

ClassCastException - if the argument is not a Long.

Since:

JDK1.2

See Also:

Comparable