Package edu.rit.pj.reduction

Class SharedCharacter

java.lang.Object
java.lang.Number
edu.rit.pj.reduction.SharedCharacter
All Implemented Interfaces:
Serializable
public class SharedCharacter extends Number
Class SharedCharacter provides a reduction variable for a value of type char.

Class SharedCharacter is multiple thread safe. The methods use lock-free atomic compare-and-set.

Note: Class SharedCharacter is implemented using class java.util.concurrent.atomic.AtomicInteger. The character value is stored as an int whose values are restricted to the range of type char.

Version:
07-Jun-2007
Author:
Alan Kaminsky
See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    SharedCharacter()
    Construct a new character reduction variable with the initial value 0.
    SharedCharacter(char initialValue)
    Construct a new character reduction variable with the given initial value.

  • Method Summary

    Modifier and Type
    Method
    Description
    char
    addAndGet(char value)
    Add the given value to this reduction variable and return the new value.
    boolean
    compareAndSet(char expect, char update)
    Atomically set this reduction variable to the given updated value if the current value equals the expected value.
    char
    decrementAndGet()
    Subtract one from this reduction variable and return the new value.
    double
    doubleValue()
    Returns this reduction variable's current value converted to type double.
    float
    floatValue()
    Returns this reduction variable's current value converted to type float.
    char
    get()
    Returns this reduction variable's current value.
    char
    getAndAdd(char value)
    Add the given value to this reduction variable and return the previous value.
    char
    getAndDecrement()
    Subtract one from this reduction variable and return the previous value.
    char
    getAndIncrement()
    Add one to this reduction variable and return the previous value.
    char
    getAndSet(char value)
    Set this reduction variable to the given value and return the previous value.
    char
    incrementAndGet()
    Add one to this reduction variable and return the new value.
    int
    intValue()
    Returns this reduction variable's current value converted to type int.
    long
    longValue()
    Returns this reduction variable's current value converted to type long.
    char
    reduce(char value, CharacterOp op)
    Combine this reduction variable with the given value using the given operation.
    void
    set(char value)
    Set this reduction variable to the given value.
    String
    toString()
    Returns a string version of this reduction variable.
    boolean
    weakCompareAndSet(char expect, char update)
    Atomically set this reduction variable to the given updated value if the current value equals the expected value.

    Methods inherited from class java.lang.Number

    byteValue, shortValue

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • SharedCharacter

      public SharedCharacter()
      Construct a new character reduction variable with the initial value 0.

    • SharedCharacter

      public SharedCharacter(char initialValue)
      Construct a new character reduction variable with the given initial value.
      Parameters:
      initialValue - Initial value.

  • Method Details

    • get

      public char get()
      Returns this reduction variable's current value.
      Returns:
      Current value.

    • set

      public void set(char value)
      Set this reduction variable to the given value.
      Parameters:
      value - New value.

    • getAndSet

      public char getAndSet(char value)
      Set this reduction variable to the given value and return the previous value.
      Parameters:
      value - New value.
      Returns:
      Previous value.

    • compareAndSet

      public boolean compareAndSet(char expect, char update)
      Atomically set this reduction variable to the given updated value if the current value equals the expected value.
      Parameters:
      expect - Expected value.
      update - Updated value.
      Returns:
      True if the update happened, false otherwise.

    • weakCompareAndSet

      public boolean weakCompareAndSet(char expect, char update)
      Atomically set this reduction variable to the given updated value if the current value equals the expected value. May fail spuriously.
      Parameters:
      expect - Expected value.
      update - Updated value.
      Returns:
      True if the update happened, false otherwise.

    • getAndIncrement

      public char getAndIncrement()
      Add one to this reduction variable and return the previous value.
      Returns:
      Previous value.

    • getAndDecrement

      public char getAndDecrement()
      Subtract one from this reduction variable and return the previous value.
      Returns:
      Previous value.

    • getAndAdd

      public char getAndAdd(char value)
      Add the given value to this reduction variable and return the previous value.
      Parameters:
      value - Value to add.
      Returns:
      Previous value.

    • incrementAndGet

      public char incrementAndGet()
      Add one to this reduction variable and return the new value.
      Returns:
      New value.

    • decrementAndGet

      public char decrementAndGet()
      Subtract one from this reduction variable and return the new value.
      Returns:
      New value.

    • addAndGet

      public char addAndGet(char value)
      Add the given value to this reduction variable and return the new value.
      Parameters:
      value - Value to add.
      Returns:
      New value.

    • reduce

      public char reduce(char value, CharacterOp op)
      Combine this reduction variable with the given value using the given operation. The result is stored back into this reduction variable and is returned.
      Parameters:
      value - Value.
      op - Binary operation.
      Returns:
      (This variable) op (value).

    • toString

      public String toString()
      Returns a string version of this reduction variable.
      Overrides:
      toString in class Object
      Returns:
      String version.

    • intValue

      public int intValue()
      Returns this reduction variable's current value converted to type int.
      Specified by:
      intValue in class Number
      Returns:
      Current value.

    • longValue

      public long longValue()
      Returns this reduction variable's current value converted to type long.
      Specified by:
      longValue in class Number
      Returns:
      Current value.

    • floatValue

      public float floatValue()
      Returns this reduction variable's current value converted to type float.
      Specified by:
      floatValue in class Number
      Returns:
      Current value.

    • doubleValue

      public double doubleValue()
      Returns this reduction variable's current value converted to type double.
      Specified by:
      doubleValue in class Number
      Returns:
      Current value.