| Version: | 0.2.4 |
| Date: | 2015-11-25 |
| Title: | R Dependency Injection |
| Author: | Lev Kuznetsov |
| Maintainer: | Lev Kuznetsov <levk@jimmy.harvard.edu> |
| Depends: | R (≥ 3.1.0) |
| Suggests: | testthat |
| Description: | R dependency injection framework. Dependency injection allows a program design to follow the dependency inversion principle. The user delegates to external code (the injector) the responsibility of providing its dependencies. This separates the responsibilities of use and construction. |
| License: | LGPL (≥ 3) |
| URL: | https://github.com/dfci-cccb/injectoR |
| BugReports: | https://github.com/dfci-cccb/injectoR/issues |
| RoxygenNote: | 5.0.1 |
| NeedsCompilation: | no |
| Packaged: | 2015-11-25 19:43:15 UTC; levk |
| Repository: | CRAN |
| Date/Publication: | 2015-11-30 08:17:48 |
Dependency injection framework
Description
Dependency injection framework
Author(s)
levk
Binder factory
Description
Binder factory
Usage
binder(parent = .binder, callback = function(binder) binder)
Arguments
parent |
of the new binder, injection will propagate up the parent stack looking for keys; if omitted defaults to root binder |
callback |
called with the newly created binder and the result is returned; if omitted just the new binder is returned |
Value
result of the injected callback if one is specified, otherwise the new binder
Examples
b <- binder ()
Default scope, bindings are provisioned each time a bean is injected
Description
Default scope, bindings are provisioned each time a bean is injected
Usage
default(provider)
Arguments
provider |
unscoped delegate, no argument function responsible for provision |
Creates a key to factory binding
Description
Creates a key to factory binding
Usage
define(..., scope = default, binder = .binder)
Arguments
... |
injectable bean identifier to factory mappings, the key is the name is matched to a parameter name during injection, the factory responsible for provisioning of the bean, a factory may accept any number of arguments in which case the framework will attempt to inject the argument if a binding to the parameter name exists; if it does not, that argument will not be injected, in which case it is the factory's responsibility to deal with a missing argument |
scope |
of the bean, wraps the injected factory call specifying provisioning strategy, if omitted a new bean instance will be provisioned each time injection is requested; injectoR also ships with with the singleton scope which will provide once and cache the bean for subsequent calls. Interface allows for custom scoping, the scope parameter must be a function accepting key (name) and the provider - the wrapped injected factory call - a function accepting no parameters responsible for actual provisioning |
binder |
for this binding, if omitted the new binding is added to the root binder |
Examples
define (hello = function () 'world', binder = binder ())
Injects the callback function
Description
Injects the callback function
Usage
inject(callback, binder = .binder)
Arguments
callback |
function to inject, a function accepting arguments to be matched to injectable keys; no errors are thrown if no binding is found for a key, this is the intended mechanic for optional injection, if the callback is able to deal with a missing argument the argument becomes optional |
binder |
containing the injectables, defaults to root binder if omitted |
Value
result of the injected callback evaluation
Examples
inject (function (two) two, define (two = function () 2, binder = binder ()))
inject (function (power) power (2, 4),
define (power = function (power) function (x, n) if (n < 1) 1 else x * power (x, n - 1)))
inject (function (fibonacci) fibonacci (8),
define (fibonacci = function (fibonacci)
function (n) if (n < 3) 1
else fibonacci (n - 1) + fibonacci (n - 2), binder = binder ()))
Aggregates multiple factories under one key
Description
Aggregates multiple factories under one key
Usage
multibind(key, scope = default, combine = function(this, parent)
base::c(this, parent), binder = .binder)
Arguments
key |
injectable bean identifier |
scope |
of the bean, wraps the injected factory call specifying provisioning strategy, if omitted a new bean instance will be provisioned each time injection is requested; injectoR also ships with with the singleton scope which will provide once and cache the bean for subsequent calls. Interface allows for custom scoping, the scope parameter must be a function accepting key (name) and the provider - the wrapped injected factory call - a function accepting no parameters responsible for actual provisioning |
combine |
aggregation procedure for combination of context and inherited values, a function accepting a list of injectable values from the current binder context and a no argument function to retrieve values of the parent context; if omitted will the binding will aggregate all values |
binder |
for this binding, if omitted the binding is added to the root binder |
Value
a function accepting one or more factories for adding elements to the binding; naming the factories will result in named values injected; optionally accepts a scope for the bindings, if omitted defaults to provide on injection; please be aware that the scope is called without key for unnamed multibinding
Examples
multibind ('keys', binder = binder ()) (function () 'skeleton')
Shims libraries
Description
Shims libraries
Usage
shim(..., library.paths = .libPaths(), callback = function() binder,
binder = .binder)
Arguments
... |
zero or more library names to shim binding each exported variable to the binder; if a library name is specified in a named list format (for example shim(s4='stats4',callback=function(s4.AIC))) all exported variable names from that library will be prepended with that name and a dot (as in the example); if a library cannot be loaded, no bindings are created for that library and no errors are thrown (but there is an error to console as reported by requireNamespace) |
library.paths |
to use for loading namespace |
callback |
injected for convenience using the binder specified after shim is completed, if omitted the call returns the binder |
binder |
for this shim |
Value
result of the callback if specified, binder otherwise
Examples
shim ('injectoR', callback = function (inject) inject, binder = binder ())
Singleton scope, bindings of this scope are provided once, on initial demand
Description
Singleton scope, bindings of this scope are provided once, on initial demand
Usage
singleton(provider)
Arguments
provider |
unscoped delegate, no argument function responsible for provision |
Examples
define (three = function () 3, scope = singleton, binder = binder ())