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PoolingService class
A singleton service to maintain a pool of resources. This pool service can be bound to different keys to represent multiple pools. Each binding is a singleton so that the state stays the same for injections into multiple instances for other artifacts.
Signature:
export declare class PoolingService<T> implements LifeCycleObserver
Implements: LifeCycleObserver
Remarks
Some resources can be expensive to create/start. For example, a datasource has overhead to connect to the database. There will be performance penalty to use TRANSIENT scope and creates a new instance per request. But it is not feasible to be a singleton for some use cases, for example, each request may have different security contexts.
The pool service observes life cycle events to start and stop.
Constructors
| Constructor | Modifiers | Description |
|---|---|---|
| (constructor)(context, options) | Constructs a new instance of the PoolingService class |
Properties
| Property | Modifiers | Type | Description |
|---|---|---|---|
| context | readonly |
Context | |
| pool | readonly |
Pool<T> | The resource pool |
Methods
| Method | Modifiers | Description |
|---|---|---|
| acquire(requestCtx) | Acquire a new instance | |
| destroy(resource) | Destroy a resource from the pool | |
| release(resource) | Release the resource back to the pool. | |
| run(task, requestCtx) | Run the task with an acquired resource from the pool. If task is completed successfully, the resource is returned to the pool. Otherwise, the resource is destroyed. | |
| start() | Start the pool | |
| stop() | Stop the pool |