SynchronizedInt

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EDU.oswego.cs.dl.util.concurrent
Class SynchronizedInt

java.lang.Object
  EDU.oswego.cs.dl.util.concurrent.SynchronizedVariable
      EDU.oswego.cs.dl.util.concurrent.SynchronizedInt

All Implemented Interfaces:: java.lang.Cloneable, java.lang.Comparable, Executor

public class SynchronizedInt
extends SynchronizedVariable
implements java.lang.Comparable, java.lang.Cloneable

A class useful for offloading synch for int instance variables.

[ Introduction to this package. ]

Field Summary

protected int value_


Fields inherited from class EDU.oswego.cs.dl.util.concurrent.SynchronizedVariable

lock_

Constructor Summary

SynchronizedInt(int initialValue)
          Make a new SynchronizedInt with the given initial value, and using its own internal lock.

SynchronizedInt(int initialValue, java.lang.Object lock)
          Make a new SynchronizedInt with the given initial value, and using the supplied lock.

Method Summary

int add(int amount)
          Add amount to value (i.e., set value += amount)

int and(int b)
          Set value to value & b.

boolean commit(int assumedValue, int newValue)
          Set value to newValue only if it is currently assumedValue.

int compareTo(int other)


int compareTo(java.lang.Object other)
          Compares this object with another, and returns a numerical result based on the comparison.

int compareTo(SynchronizedInt other)


int complement()
          Set the value to its complement

int decrement()
          Decrement the value.

int divide(int factor)
          Divide value by factor (i.e., set value /= factor)

boolean equals(java.lang.Object other)
          Determine whether this Object is semantically equal to another Object.

int get()
          Return the current value

int hashCode()
          Get a value that represents this Object, as uniquely as possible within the confines of an int.

int increment()
          Increment the value.

int multiply(int factor)
          Multiply value by factor (i.e., set value *= factor)

int negate()
          Set the value to the negative of its old value

int or(int b)
          Set value to value | b.

int set(int newValue)
          Set to newValue.

int subtract(int amount)
          Subtract amount from value (i.e., set value -= amount)

int swap(SynchronizedInt other)
          Atomically swap values with another SynchronizedInt.

java.lang.String toString()
          Convert this Object to a human-readable String.

int xor(int b)
          Set value to value ^ b.

Methods inherited from class EDU.oswego.cs.dl.util.concurrent.SynchronizedVariable

execute, getLock

Methods inherited from class java.lang.Object

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

Field Detail

value_

protected int value_

Constructor Detail

SynchronizedInt

public SynchronizedInt(int initialValue)

Make a new SynchronizedInt with the given initial value, and using its own internal lock.

SynchronizedInt

public SynchronizedInt(int initialValue,
                       java.lang.Object lock)

Make a new SynchronizedInt with the given initial value, and using the supplied lock.

Method Detail

get

public final int get()

Return the current value

set

public int set(int newValue)

Set to newValue.

commit

public boolean commit(int assumedValue,
                      int newValue)

Set value to newValue only if it is currently assumedValue.

swap

public int swap(SynchronizedInt other)

Atomically swap values with another SynchronizedInt. Uses identityHashCode to avoid deadlock when two SynchronizedInts attempt to simultaneously swap with each other. (Note: Ordering via identyHashCode is not strictly guaranteed by the language specification to return unique, orderable values, but in practice JVMs rely on them being unique.)

increment

public int increment()

Increment the value.

decrement

public int decrement()

Decrement the value.

add

public int add(int amount)

Add amount to value (i.e., set value += amount)

subtract

public int subtract(int amount)

Subtract amount from value (i.e., set value -= amount)

multiply

public int multiply(int factor)

Multiply value by factor (i.e., set value *= factor)

divide

public int divide(int factor)

Divide value by factor (i.e., set value /= factor)

negate

public int negate()

Set the value to the negative of its old value

complement

public int complement()

Set the value to its complement

and

public int and(int b)

Set value to value & b.

or

public int or(int b)

Set value to value | b.

xor

public int xor(int b)

Set value to value ^ b.

compareTo

public int compareTo(int other)

compareTo

public int compareTo(SynchronizedInt other)

compareTo

public int compareTo(java.lang.Object other)

Description copied from interface: java.lang.Comparable

Compares this object with another, and returns a numerical result based on the comparison. If the result is negative, this object sorts less than the other; if 0, the two are equal, and if positive, this object sorts greater than the other. To translate this into boolean, simply perform o1.compareTo(o2) <op> 0, where op is one of <, <=, =, !=, >, or >=.

You must make sure that the comparison is mutual, ie. sgn(x.compareTo(y)) == -sgn(y.compareTo(x)) (where sgn() is defined as -1, 0, or 1 based on the sign). This includes throwing an exception in either direction if the two are not comparable; hence, compareTo(null) should always throw an Exception.

You should also ensure transitivity, in two forms: x.compareTo(y) > 0 && y.compareTo(z) > 0 implies x.compareTo(z) > 0; and x.compareTo(y) == 0 implies x.compareTo(z) == y.compareTo(z).

Specified by:: compareTo in interface java.lang.Comparable

equals

public boolean equals(java.lang.Object other)

Description copied from class: java.lang.Object

Determine whether this Object is semantically equal to another Object.

There are some fairly strict requirements on this method which subclasses must follow:

It must be transitive. If a.equals(b) and b.equals(c), then a.equals(c) must be true as well.
It must be symmetric. a.equals(b) and b.equals(a) must have the same value.
It must be reflexive. a.equals(a) must always be true.
It must be consistent. Whichever value a.equals(b) returns on the first invocation must be the value returned on all later invocations.
a.equals(null) must be false.
It must be consistent with hashCode(). That is, a.equals(b) must imply a.hashCode() == b.hashCode(). The reverse is not true; two objects that are not equal may have the same hashcode, but that has the potential to harm hashing performance.

This is typically overridden to throw a java.lang.ClassCastException if the argument is not comparable to the class performing the comparison, but that is not a requirement. It is legal for a.equals(b) to be true even though a.getClass() != b.getClass(). Also, it is typical to never cause a java.lang.NullPointerException.

In general, the Collections API (java.util) use the equals method rather than the == operator to compare objects. However, java.util.IdentityHashMap is an exception to this rule, for its own good reasons.

The default implementation returns this == o.

hashCode

public int hashCode()

Description copied from class: java.lang.Object

Get a value that represents this Object, as uniquely as possible within the confines of an int.

There are some requirements on this method which subclasses must follow:

Semantic equality implies identical hashcodes. In other words, if a.equals(b) is true, then a.hashCode() == b.hashCode() must be as well. However, the reverse is not necessarily true, and two objects may have the same hashcode without being equal.
It must be consistent. Whichever value o.hashCode() returns on the first invocation must be the value returned on all later invocations as long as the object exists. Notice, however, that the result of hashCode may change between separate executions of a Virtual Machine, because it is not invoked on the same object.

Notice that since hashCode is used in java.util.Hashtable and other hashing classes, a poor implementation will degrade the performance of hashing (so don't blindly implement it as returning a constant!). Also, if calculating the hash is time-consuming, a class may consider caching the results.

The default implementation returns System.identityHashCode(this)

toString

public java.lang.String toString()

Description copied from class: java.lang.Object

Convert this Object to a human-readable String. There are no limits placed on how long this String should be or what it should contain. We suggest you make it as intuitive as possible to be able to place it into System.out.println() 55 and such.

It is typical, but not required, to ensure that this method never completes abruptly with a java.lang.RuntimeException.

This method will be called when performing string concatenation with this object. If the result is null, string concatenation will instead use "null".

The default implementation returns getClass().getName() + "@" + Integer.toHexString(hashCode()).

Overview

Package

Class

Use

Deprecated

Index

Home >> All >> EDU >> oswego >> cs >> dl >> util >> [ concurrent overview ]

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SUMMARY:

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Constructor Summary
`SynchronizedInt(int initialValue)` Make a new SynchronizedInt with the given initial value, and using its own internal lock.
`SynchronizedInt(int initialValue, java.lang.Object lock)` Make a new SynchronizedInt with the given initial value, and using the supplied lock.

Method Summary
`int`	`add(int amount)` Add amount to value (i.e., set value += amount)
`int`	`and(int b)` Set value to value & b.
`boolean`	`commit(int assumedValue, int newValue)` Set value to newValue only if it is currently assumedValue.
`int`	`compareTo(int other)`
`int`	`compareTo(java.lang.Object other)` Compares this object with another, and returns a numerical result based on the comparison.
`int`	`compareTo(SynchronizedInt other)`
`int`	`complement()` Set the value to its complement
`int`	`decrement()` Decrement the value.
`int`	`divide(int factor)` Divide value by factor (i.e., set value /= factor)
`boolean`	`equals(java.lang.Object other)` Determine whether this Object is semantically equal to another Object.
`int`	`get()` Return the current value
`int`	`hashCode()` Get a value that represents this Object, as uniquely as possible within the confines of an int.
`int`	`increment()` Increment the value.
`int`	`multiply(int factor)` Multiply value by factor (i.e., set value *= factor)
`int`	`negate()` Set the value to the negative of its old value
`int`	`or(int b)` Set value to value \| b.
`int`	`set(int newValue)` Set to newValue.
`int`	`subtract(int amount)` Subtract amount from value (i.e., set value -= amount)
`int`	`swap(SynchronizedInt other)` Atomically swap values with another SynchronizedInt.
`java.lang.String`	`toString()` Convert this Object to a human-readable String.
`int`	`xor(int b)` Set value to value ^ b.

EDU.oswego.cs.dl.util.concurrent Class SynchronizedInt

value_

SynchronizedInt

SynchronizedInt

get

set

commit

swap

increment

decrement

add

subtract

multiply

divide

negate

complement

and

or

xor

compareTo

compareTo

compareTo

equals

hashCode

toString

EDU.oswego.cs.dl.util.concurrent
Class SynchronizedInt