Common Thread Types
Much of the functionality of threads is provided through the classes
in the System.Threading
namespace. The most basic thread
class to understand is the Monitor
class, which is explained
next.
The Monitor Class
The System.Threading.Monitor
class provides an implementation
of Hoare’s Monitor that allows you to use any reference-type instance as a
monitor.
The Enter and Exit Methods
The Enter()
and Exit()
methods
respectively obtain and release a lock on an object. If the object is already
held by another thread, Enter()
waits until the lock is
released, or the thread is interrupted by a ThreadInterruptedException
.
Every call to Enter()
for a given object on a thread should
be matched with a call to Exit()
for the same object on
the same thread.
The TryEnter Methods
The TryEnter()
methods are similar to the Enter()
method,
but they don’t require a lock on the object to proceed. These methods return
true
if the lock is obtained, and false
if it isn’t, optionally passing in
a timeout parameter that specifies the maximum time to wait for the other
threads to relinquish the lock.
The Wait Methods
The thread holding a lock on an object may call one of the Wait()
methods
to temporarily release the lock and block itself, while it waits for another
thread to notify it by executing a pulse on the monitor. This approach can
tell a worker thread there is work to perform on that object. The overloaded
versions of Wait()
allow you to specify a timeout that reactivates the thread if ...
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