Added condition variable and timeout to ObjectPool::borrowObject/returnObject to block caller until an object is available.

This commit is contained in:
Matej Kenda 2015-05-27 14:01:39 +02:00
parent 9ce48223e9
commit 01fc7f2e1c
2 changed files with 30 additions and 13 deletions

View File

@ -22,6 +22,7 @@
#include "Poco/Poco.h"
#include "Poco/Mutex.h"
#include "Poco/Condition.h"
#include "Poco/AutoPtr.h"
#include "Poco/SharedPtr.h"
#include <vector>
@ -157,7 +158,7 @@ class ObjectPool
/// removed from the pool, activated (using the factory) and returned.
/// - Otherwise, if the peak capacity of the pool has not yet been reached,
/// a new object is created and activated, using the object factory, and returned.
/// - If the peak capacity has already been reached, null is returned.
/// - If the peak capacity has already been reached, null is returned after timeout.
///
/// When an object is returned to the pool:
/// - If the object is valid (checked by calling validateObject()
@ -207,33 +208,47 @@ public:
}
}
P borrowObject()
P borrowObject(long timeoutMilliseconds = 0)
/// Obtains an object from the pool, or creates a new object if
/// possible.
///
/// Returns null if no object is available.
/// Returns null if no object is available after timeout.
///
/// If activating the object fails, the object is destroyed and
/// the exception is passed on to the caller.
{
Poco::FastMutex::ScopedLock lock(_mutex);
if (!_pool.empty())
{
P pObject = _pool.back();
_pool.pop_back();
return activateObject(pObject);
}
else if (_size < _peakCapacity)
if (_size >= _peakCapacity)
{
P pObject = _factory.createObject();
activateObject(pObject);
_size++;
return pObject;
if (timeoutMilliseconds == 0)
{
return 0;
}
while (_size >= _peakCapacity)
{
if ( !_availableCondition.tryWait(_mutex, timeoutMilliseconds))
{
// timeout
return 0;
}
}
}
else return 0;
// _size < _peakCapacity
P pObject = _factory.createObject();
activateObject(pObject);
_size++;
return pObject;
}
void returnObject(P pObject)
/// Returns an object to the pool.
{
@ -250,6 +265,7 @@ public:
{
_factory.destroyObject(pObject);
_size--;
_availableCondition.signal();
}
}
else
@ -308,6 +324,7 @@ private:
std::size_t _size;
std::vector<P> _pool;
mutable Poco::FastMutex _mutex;
Poco::Condition _availableCondition;
};

View File

@ -77,9 +77,9 @@ class PooledConnection
/// Helper class for borrowing and returning a connection automatically from a pool.
{
public:
PooledConnection(Poco::ObjectPool<Connection, Connection::Ptr>& pool) : _pool(pool)
PooledConnection(Poco::ObjectPool<Connection, Connection::Ptr>& pool, long timeoutMilliseconds = 0) : _pool(pool)
{
_connection = _pool.borrowObject();
_connection = _pool.borrowObject(timeoutMilliseconds);
}
virtual ~PooledConnection()