# What's New With 6.6.0

## Major Updates

### WireBox Child Injectors

![](/files/hZcbL08eDS0wZ9BBu34c)

Welcome to the world of hierarchical dependency injection.  We had the ability before to add a parent injector to WireBox, but now you can not only add a parent, but also many children to the hierarchy.

Every injector has the capability to store an ordered collection (`ordered struct`) of child injectors via the `childInjectors` property. Child injectors are used internally in many instances to provide a hierarchical approach to DI where instances can be searched for locally, in the parent and in the children. Here are some of the new methods to assist with child injectors:

* `hasChildInjector( name )` - Verify if a child injector has been registered
* `registerChildInjector( name, child )` - Register a child injector by name
* `removeChildInjector( name )` - Remove a child injector by name
* `getChildInjector( name )` - Get a child injector by name
* `getChildInjectors()` - Get all the child injectors registered
* `getChildInjectorNames()` - Get an array of all the registered child injectors

#### Child Enhanced Methods

* `getInstance()`
  * The `getInstance()`method now has an `injector` argument so you can **EXPLICITLY** request an instance from a child injector by name `getInstance( name : "service", injector : "childInjector" )`
  * Apart from the explicit lookup it can also do implicit hierarchical lookups using the following order:
    * Locally
    * Parent
    * All Children (in order of registration)
* `containsInstance( name )` - This method now also searches in the child collection for the specific `name` instance. The lookup searches in the following order:
  1. Locally
  2. Parent
  3. Children
* `shutdown()` - The shutdown method has been enhanced to issue shutdown method calls to all child injectors registered.

#### Getting Instances From Specific Child Injectors

The `getInstance()` has been modified to have an `injector` argument that you can use to specifically ask for an instance from that child injector. If the child injector has not been registered you will get a `InvalidChildInjector` Exception.

```javascript
getInstance( name: "CategoryService", injector : "ChildInjector" )
```

#### Child Injector Explicit DSL

The following is the DSL you can use to **explicitly** target a child injector for a dependency. You will prefix it with `wirebox:child:{name}` and the name of the injector:

```javascript
// Use the property name as the instance name
property name="categoryService" inject="wirebox:child:childInjector"
// Use a specific instance name
property name="categoryService" inject="wirebox:child:childInjector:CategoryService"
// Use any DSL
property name="categoryService" inject="wirebox:child:childInjector:{DSL}"
```

#### IInjector Interface Updates

The `coldbox.system.ioc.IInjector` interface's `getInstance()` method has been modified to include support for child injector retrievals:

```javascript
/**
 * Locates, Creates, Injects and Configures an object model instance
 *
 * @name The mapping name or CFC instance path to try to build up
 * @initArguments The constructor structure of arguments to passthrough when initializing the instance
 * @dsl The dsl string to use to retrieve the instance model object, mutually exclusive with 'name'
 * @targetObject The object requesting the dependency, usually only used by DSL lookups
 * @injector The child injector name to use when retrieving the instance
 */
function getInstance(
	name,
	struct initArguments,
	dsl,
	targetObject = "",
	injector
);
```

### Release Notes

{% tabs %}
{% tab title="WireBox" %}

#### Bug

* [WIREBOX-124](https://ortussolutions.atlassian.net/browse/WIREBOX-124) Killing `IInjector` interface usages due to many issues across cfml engines, leaving them for docs only
* [WIREBOX-118](https://ortussolutions.atlassian.net/browse/WIREBOX-118) Never override an existing variables key with virtual inheritance

#### Improvement

* [WIREBOX-120](https://ortussolutions.atlassian.net/browse/WIREBOX-120) DSLs process method now receives the caller `targetID` alongside the `targetObject` and the `target` definition

#### New Feature

* [WIREBOX-122](https://ortussolutions.atlassian.net/browse/WIREBOX-122) New wirebox DSL to inject the target's metadata that's cached in the target's binder: `wirebox:objectMetadata`
* [WIREBOX-121](https://ortussolutions.atlassian.net/browse/WIREBOX-121) New WireBoxDSL: `wirebox:targetID` to give you back the target ID used when injecting the object
* [WIREBOX-119](https://ortussolutions.atlassian.net/browse/WIREBOX-119) Missing `coldbox:schedulerService` DSL
* [WIREBOX-117](https://ortussolutions.atlassian.net/browse/WIREBOX-117) HDI - Ability for injectors to have a collection of child injectors to delegate lookups to, basically Hierarchical DI

#### Task

* [WIREBOX-123](https://ortussolutions.atlassian.net/browse/WIREBOX-123) Removal of usage of Injector dsl interface due to so many issues with multiple engines.
  {% endtab %}

{% tab title="CacheBox" %}

#### Bug

* [CACHEBOX-76](https://ortussolutions.atlassian.net/browse/CACHEBOX-76) Fixed method return value + SQL compatibility on jdbc metadata indexer thanks to @homestar9
* [CACHEBOX-75](https://ortussolutions.atlassian.net/browse/CACHEBOX-75) reap operation was not ignoring 0 values for last access timeouts
* [CACHEBOX-74](https://ortussolutions.atlassian.net/browse/CACHEBOX-74) Typo in queryExecute Attribute "datasource" in the JDBCStore.cfc

#### Improvement

* [CACHEBOX-73](https://ortussolutions.atlassian.net/browse/CACHEBOX-73) Replace IIF and urlEncodedFormat on cache content reports
* [CACHEBOX-79](https://ortussolutions.atlassian.net/browse/CACHEBOX-79) Lower logging verbosity of cache reaping from info to debug messages
  {% endtab %}
  {% endtabs %}


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