Joins is an asynchronous
concurrent computing
Concurrent computing is a form of computing in which several computations are executed '' concurrently''—during overlapping time periods—instead of ''sequentially—''with one completing before the next starts.
This is a property of a syst ...
API
An application programming interface (API) is a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how to build ...
(
Join-pattern
Join-patterns provides a way to write concurrent, parallel and distributed computer programs by message passing. Compared to the use of threads and locks, this is a high level programming model using communication constructs model to abstra ...
) from
Microsoft Research
Microsoft Research (MSR) is the research subsidiary of Microsoft. It was created in 1991 by Richard Rashid, Bill Gates and Nathan Myhrvold with the intent to advance state-of-the-art computing and solve difficult world problems through technologi ...
for the
.NET Framework. It is based on
join calculus and makes the concurrency constructs of the
Cω
Language Integrated Query (LINQ, pronounced "link") is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages, originally released as a major part of .NET Framework 3.5 in 2007.
LINQ extends the ...
language available as a
CLI assembly that any
CLI compliant language can use.
Overview
Joins can be used to express concurrency in an application using the joins pattern, usable both for multi-threaded applications as well as for event based
distributed Distribution may refer to:
Mathematics
*Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations
*Probability distribution, the probability of a particular value or value range of a varia ...
applications. The Joins API emulates declarative
type-safe
In computer science, type safety and type soundness are the extent to which a programming language discourages or prevents type errors. Type safety is sometimes alternatively considered to be a property of facilities of a computer language; that i ...
expression of synchronization patterns.
The Joins library emulates asynchronous and synchronous methods. An asynchronous method, in Cω and Joins parlance, is one which does not block the caller method, nor does it return any result, whereas a synchronous method blocks the caller method. In the Joins API, synchronous as well as asynchronous methods are implemented as
generic delegates. Usage of generics provide type safety. For example, a set of synchronous and asynchronous method can be created and using them to create an object that implements the pattern, as:
public class JoinDemo
When asynchronous methods are called, the parameters are put in a channel, which is a queue managed by the Joins runtime. The method can optionally start a new thread to process the parameters in the background, and return the results. When the corresponding synchronous method is called the parameter is returned for further processing. If no parameter is present in the queue when the synchronous method is called, the caller stalls. The Joins runtime schedules which parameter is returned based on whether it is ready.
The synchronization pattern of the methods are defined by ''joins patterns'', which describes what happens when a set of channels are invoked. For example, what happens when ''Send'' and ''Retrieve'' are called together can be different than ''Send'' and ''Queue''.
public void SetPatterns()
References
The Joins Concurrency LibraryJoins — A Concurrency Library
External links
Joins at Microsoft Research
Concurrent programming libraries
Microsoft Research
Articles with example Java code
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