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Class core.sync.condition.Condition
This class represents a condition variable as conceived by C.A.R. Hoare. As per Mesa type monitors however, "signal" has been replaced with "notify" to indicate that control is not transferred to the waiter when a notification is sent.
class Condition
;
Constructors
Name | Description |
---|---|
this
(m)
|
Initializes a condition object which is associated with the supplied mutex object. |
Properties
Name | Type | Description |
---|---|---|
mutex [get]
|
Mutex | Gets the mutex associated with this condition. |
Methods
Name | Description |
---|---|
notify
()
|
Notifies one waiter. |
notifyAll
()
|
Notifies all waiters. |
wait
()
|
Wait until notified. |
wait
(val)
|
Suspends the calling thread until a notification occurs or until the supplied time period has elapsed. |
factory
(classname)
|
Create instance of class specified by the fully qualified name classname. The class must either have no constructors or have a default constructor. |
opCmp
(o)
|
Compare with another Object obj. |
opEquals
(o)
|
Test whether this is equal to o .
The default implementation only compares by identity (using the is operator).
Generally, overrides and overloads for opEquals should attempt to compare objects by their contents.
A class will most likely want to add an overload that takes your specific type as the argument
and does the content comparison. Then you can override this and forward it to your specific
typed overload with a cast. Remember to check for null on the typed overload.
|
toHash
()
|
Compute hash function for Object. |
toString
()
|
Convert Object to a human readable string. |
Example
import core .thread;
import core .sync .mutex;
import core .sync .semaphore;
void testNotify()
{
auto mutex = new Mutex;
auto condReady = new Condition( mutex );
auto semDone = new Semaphore;
auto synLoop = new Object;
int numWaiters = 10;
int numTries = 10;
int numReady = 0;
int numTotal = 0;
int numDone = 0;
int numPost = 0;
void waiter()
{
for ( int i = 0; i < numTries; ++i )
{
synchronized( mutex )
{
while ( numReady < 1 )
{
condReady .wait();
}
--numReady;
++numTotal;
}
synchronized( synLoop )
{
++numDone;
}
semDone .wait();
}
}
auto group = new ThreadGroup;
for ( int i = 0; i < numWaiters; ++i )
group .create( &waiter );
for ( int i = 0; i < numTries; ++i )
{
for ( int j = 0; j < numWaiters; ++j )
{
synchronized( mutex )
{
++numReady;
condReady .notify();
}
}
while ( true )
{
synchronized( synLoop )
{
if ( numDone >= numWaiters )
break;
}
Thread .yield();
}
for ( int j = 0; j < numWaiters; ++j )
{
semDone .notify();
}
}
group .joinAll();
writeln(numTotal); // numWaiters * numTries
}
void testNotifyAll()
{
auto mutex = new Mutex;
auto condReady = new Condition( mutex );
int numWaiters = 10;
int numReady = 0;
int numDone = 0;
bool alert = false;
void waiter()
{
synchronized( mutex )
{
++numReady;
while ( !alert )
condReady .wait();
++numDone;
}
}
auto group = new ThreadGroup;
for ( int i = 0; i < numWaiters; ++i )
group .create( &waiter );
while ( true )
{
synchronized( mutex )
{
if ( numReady >= numWaiters )
{
alert = true;
condReady .notifyAll();
break;
}
}
Thread .yield();
}
group .joinAll();
assert( numReady == numWaiters && numDone == numWaiters );
}
void testWaitTimeout()
{
auto mutex = new Mutex;
auto condReady = new Condition( mutex );
bool waiting = false;
bool alertedOne = true;
bool alertedTwo = true;
void waiter()
{
synchronized( mutex )
{
waiting = true;
// we never want to miss the notification (30s)
alertedOne = condReady .wait( dur!"seconds"(30) );
// but we don't want to wait long for the timeout (10ms)
alertedTwo = condReady .wait( dur!"msecs"(10) );
}
}
auto thread = new Thread( &waiter );
thread .start();
while ( true )
{
synchronized( mutex )
{
if ( waiting )
{
condReady .notify();
break;
}
}
Thread .yield();
}
thread .join();
assert( waiting );
assert( alertedOne );
assert( !alertedTwo );
}
testNotify();
testNotifyAll();
testWaitTimeout();
Authors
Sean Kelly
License
Copyright © 1999-2024 by the D Language Foundation | Page generated by ddox.