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0.8.4

Asynchronous I/O that doesn’t get in your way, written in D

Class ConnectionPool

Generic connection pool class.

class ConnectionPool(Connection) ;

The connection pool is creating connections using the supplied factory function as needed whenever lockConnection is called. Connections are associated to the calling fiber, as long as any copy of the returned LockedConnection object still exists. Connections that are not associated to any fiber will be kept in a pool of open connections for later reuse.

Note that, after retrieving a connection with lockConnection, the caller has to make sure that the connection is actually physically open and to reopen it if necessary. The ConnectionPool class has no knowledge of the internals of the connection objects.

Constructors

NameDescription
this
this

Fields

NameTypeDescription
m_connectionFactory @safe Connection delegate()
m_connections Connection[]
m_lockCount int[const(Connection)]
m_sem FreeListRef!LocalTaskSemaphore
m_thread Thread

Properties

NameTypeDescription
maxConcurrency[get, set] uintDetermines the maximum number of concurrently open connections.

Methods

NameDescription
lockConnection Retrieves a connection to temporarily associate with the calling fiber.

Example

class Connection {
	void write() {}
}

auto pool = new ConnectionPool!Connection({
	return new Connection; // perform the connection here
});

// create and lock a first connection
auto c1 = pool.lockConnection();
c1.write();

// create and lock a second connection
auto c2 = pool.lockConnection();
c2.write();

// writing to c1 will still write to the first connection
c1.write();

// free up the reference to the first connection, so that it can be reused
destroy(c1);

// locking a new connection will reuse the first connection now instead of creating a new one
auto c3 = pool.lockConnection();
c3.write();
Authors

Sönke Ludwig

Copyright

© 2012-2016 RejectedSoftware e.K.

License

Subject to the terms of the MIT license, as written in the included LICENSE.txt file.