Package java.lang

Class Long

java.lang.Object
java.lang.Number
java.lang.Long
All Implemented Interfaces:
Serializable, Comparable<Long>
public final class Long
extends Number
implements Comparable<Long>
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.

Since:
1.0
See Also:
Integer, Serialized Form

  • Field Summary

    Fields
    Modifier and Type Field Description
    static long MAX_VALUE
    Constant for the maximum long value, 263-1.
    static long MIN_VALUE
    Constant for the minimum long value, -263.
    static int SIZE
    Constant for the number of bits needed to represent a long in two's complement form.
    static Class<Long> TYPE
    The Class object that represents the primitive type long.

  • Constructor Summary

    Constructors
    Constructor Description
    Long​(long value)
    Constructs a new Long with the specified primitive long value.
    Long​(String string)
    Constructs a new Long from the specified string.

  • Method Summary

    Modifier and Type Method Description
    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.
    static int compare​(long lhs, long rhs)
    Compares two long values.
    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)
    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, Long defaultValue)
    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)
    Parses the specified string as a signed decimal long value.
    static long parseLong​(String string, int radix)
    Parses the specified string as a signed long value using the specified radix.
    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​(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.
    static Long valueOf​(String string, int radix)
    Parses the specified string as a signed long value using the specified radix.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • MAX_VALUE

      public static final long MAX_VALUE
      Constant for the maximum long value, 263-1.
      See Also:
      Constant Field Values

    • MIN_VALUE

      public static final long MIN_VALUE
      Constant for the minimum long value, -263.
      See Also:
      Constant Field Values

    • TYPE

      public static final Class<Long> TYPE
      The Class object that represents the primitive type long.

    • SIZE

      public static final int SIZE
      Constant for the number of bits needed to represent a long in two's complement form.
      Since:
      1.5
      See Also:
      Constant Field Values

  • Constructor Details

    • Long

      public Long​(long value)
      Constructs a new Long with the specified primitive long value.
      Parameters:
      value - the primitive long value to store in the new instance.

    • Long

      public Long​(String string) throws NumberFormatException
      Constructs a new Long from the specified string.
      Parameters:
      string - the string representation of a long value.
      Throws:
      NumberFormatException - if string cannot be parsed as a long value.
      See Also:
      parseLong(String)

  • Method Details

    • byteValue

      public byte byteValue()
      Description copied from class: Number
      Returns this object's value as a byte. Might involve rounding and/or truncating the value, so it fits into a byte.
      Overrides:
      byteValue in class Number
      Returns:
      the primitive byte value of this object.

    • compareTo

      public int compareTo​(Long object)
      Compares this object to the specified long object to determine their relative order.
      Specified by:
      compareTo in interface Comparable<Long>
      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.
      Since:
      1.2
      See Also:
      Comparable

    • compare

      public static int compare​(long lhs, long rhs)
      Compares two long values.
      Returns:
      0 if lhs = rhs, less than 0 if lhs < rhs, and greater than 0 if lhs > rhs.
      Since:
      1.7

    • decode

      public static Long decode​(String string) throws NumberFormatException
      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 cannot be parsed as a long value.

    • doubleValue

      public double doubleValue()
      Description copied from class: Number
      Returns this object's value as a double. Might involve rounding.
      Specified by:
      doubleValue in class Number
      Returns:
      the primitive double value of this object.

    • equals

      public boolean equals​(Object o)
      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.
      Overrides:
      equals in class Object
      Parameters:
      o - the object to compare this long with.
      Returns:
      true if the specified object is equal to this Long; false otherwise.
      See Also:
      Object.hashCode()

    • floatValue

      public float floatValue()
      Description copied from class: Number
      Returns this object's value as a float. Might involve rounding.
      Specified by:
      floatValue in class Number
      Returns:
      the primitive float value of this object.

    • getLong

      public static Long getLong​(String string)
      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.

    • getLong

      public static Long getLong​(String string, long defaultValue)
      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.

    • getLong

      public static Long getLong​(String string, Long defaultValue)
      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.

    • hashCode

      public int hashCode()
      Description copied from class: Object
      Returns an integer hash code for this object. By contract, any two objects for which Object.equals(java.lang.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.

      Overrides:
      hashCode in class Object
      Returns:
      this object's hash code.
      See Also:
      Object.equals(java.lang.Object)

    • intValue

      public int intValue()
      Description copied from class: Number
      Returns this object's value as an int. Might involve rounding and/or truncating the value, so it fits into an int.
      Specified by:
      intValue in class Number
      Returns:
      the primitive int value of this object.

    • longValue

      public long longValue()
      Gets the primitive value of this long.
      Specified by:
      longValue in class Number
      Returns:
      this object's primitive value.

    • parseLong

      public static long parseLong​(String string) throws NumberFormatException
      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 cannot be parsed as a long value.

    • parseLong

      public static long parseLong​(String string, int radix) throws NumberFormatException
      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 cannot be parsed as a long value, or radix < Character.MIN_RADIX || radix > Character.MAX_RADIX.

    • shortValue

      public short shortValue()
      Description copied from class: Number
      Returns this object's value as a short. Might involve rounding and/or truncating the value, so it fits into a short.
      Overrides:
      shortValue in class Number
      Returns:
      the primitive short value of this object.

    • toBinaryString

      public static String toBinaryString​(long v)
      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.

    • toHexString

      public static String toHexString​(long v)
      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.

    • toOctalString

      public static String toOctalString​(long v)
      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.

    • toString

      public String toString()
      Description copied from class: Object
      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.

      Overrides:
      toString in class Object
      Returns:
      a printable representation of this object.

    • toString

      public static String toString​(long n)
      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.

    • toString

      public static String toString​(long v, int radix)
      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.

    • valueOf

      public static Long valueOf​(String string) throws NumberFormatException
      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 cannot be parsed as a long value.
      See Also:
      parseLong(String)

    • valueOf

      public static Long valueOf​(String string, int radix) throws NumberFormatException
      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 cannot be parsed as a long value, or radix < Character.MIN_RADIX || radix > Character.MAX_RADIX.
      See Also:
      parseLong(String, int)

    • highestOneBit

      public 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. 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.
      Since:
      1.5

    • lowestOneBit

      public 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. 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.
      Since:
      1.5

    • numberOfLeadingZeros

      public static int numberOfLeadingZeros​(long v)
      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.
      Since:
      1.5

    • numberOfTrailingZeros

      public static int numberOfTrailingZeros​(long v)
      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.
      Since:
      1.5

    • bitCount

      public static int bitCount​(long v)
      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.
      Since:
      1.5

    • rotateLeft

      public static long rotateLeft​(long v, int distance)
      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.
      Since:
      1.5

    • rotateRight

      public static long rotateRight​(long v, int distance)
      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.
      Since:
      1.5

    • reverseBytes

      public static long reverseBytes​(long v)
      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.
      Since:
      1.5

    • reverse

      public static long reverse​(long v)
      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.
      Since:
      1.5

    • signum

      public static int signum​(long v)
      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.
      Since:
      1.5

    • valueOf

      public static Long valueOf​(long v)
      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.
      Since:
      1.5