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org.ematgine.utils.concurrent
Class SynchronizedFloat  view SynchronizedFloat download SynchronizedFloat.java

java.lang.Object
  extended byorg.ematgine.utils.concurrent.SynchronizedVariable
      extended byorg.ematgine.utils.concurrent.SynchronizedFloat
All Implemented Interfaces:
java.lang.Cloneable, java.lang.Comparable, Executor
Direct Known Subclasses:
WaitableFloat

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

A class useful for offloading synch for float instance variables.

[ Introduction to this package. ]


Field Summary
protected  float value_
           
 
Fields inherited from class org.ematgine.utils.concurrent.SynchronizedVariable
lock_
 
Constructor Summary
SynchronizedFloat(float initialValue)
          Make a new SynchronizedFloat with the given initial value, and using its own internal lock.
SynchronizedFloat(float initialValue, java.lang.Object lock)
          Make a new SynchronizedFloat with the given initial value, and using the supplied lock.
 
Method Summary
 float add(float amount)
          Add amount to value (i.e., set value += amount)
 boolean commit(float assumedValue, float newValue)
          Set value to newValue only if it is currently assumedValue.
 int compareTo(float other)
           
 int compareTo(java.lang.Object other)
          Compares this object with another, and returns a numerical result based on the comparison.
 int compareTo(SynchronizedFloat other)
           
 float divide(float 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.
 float get()
          Return the current value
 int hashCode()
          Get a value that represents this Object, as uniquely as possible within the confines of an int.
 float multiply(float factor)
          Multiply value by factor (i.e., set value *= factor)
 float set(float newValue)
          Set to newValue.
 float subtract(float amount)
          Subtract amount from value (i.e., set value -= amount)
 float swap(SynchronizedFloat other)
          Atomically swap values with another SynchronizedFloat.
 java.lang.String toString()
          Convert this Object to a human-readable String.
 
Methods inherited from class org.ematgine.utils.concurrent.SynchronizedVariable
execute, getLock
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

value_

protected float value_
Constructor Detail

SynchronizedFloat

public SynchronizedFloat(float initialValue)
Make a new SynchronizedFloat with the given initial value, and using its own internal lock.


SynchronizedFloat

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

Method Detail

get

public final float get()
Return the current value


set

public float set(float newValue)
Set to newValue.


commit

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


swap

public float swap(SynchronizedFloat other)
Atomically swap values with another SynchronizedFloat. Uses identityHashCode to avoid deadlock when two SynchronizedFloats 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.)


add

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


subtract

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


multiply

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


divide

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


compareTo

public int compareTo(float other)

compareTo

public int compareTo(SynchronizedFloat 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()).