ImmediateHelper (HK2 2.4.0 API)

java.lang.Object
- org.glassfish.hk2.internal.ImmediateHelper

All Implemented Interfaces:

Runnable, DynamicConfigurationListener, ErrorService, ImmediateController, ValidationService, Validator
```
@Singleton
 @Visibility(value=LOCAL)
public class ImmediateHelper
extends Object
implements DynamicConfigurationListener, Runnable, ValidationService, ErrorService, Validator, ImmediateController
```
The implementation of the immediate context. This should NOT be added automatically, and hence is not annotated with Service
This implementation uses a lot of facilities of hk2, so lets explain each one.
The thing that makes Immediate services immediate is that they are started as soon as they are noticed. This is done by implementing the DynamicConfigurationListener, as it will get notified when a configuration has changed. However, since the creation of user services can take an arbitrarily long time it is better to do that work on a separate thread, which is why we implement Runnable. The run method is the method that will pull from the queue of work and instantiate (and destroy) the immediate services.
However, there is also a desire to be highly efficient. This means we should not be creating this thread if there is no work for the thread to do. For this to work we need to know which configuration changes have added or removed an Immediate service. To know this we have implemented the Validation service and Validator. The validation service records the thread id of a configuration operation that is adding or removing services. This thread id goes into a map. But we have to be sure that the map does not grow without bound. To do this we clear the map both when the configuration service has succeeded (in the DynamicConfigurationListener) and when the configuration service has failed (in the ErrorService). This is why we have implemented the ErrorService.

Author:

jwells

Nested Class Summary
- Nested classes/interfaces inherited from interface org.glassfish.hk2.api.ImmediateController
  ImmediateController.ImmediateServiceState

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`configurationChanged()` This method is called when the set of descriptors in this service locator has been changed.
`Executor`	`getExecutor()` Returns the executor that is currently in use by the Immediate subsystem
`ImmediateController.ImmediateServiceState`	`getImmediateState()` Returns the state the system is currently running under
`Filter`	`getLookupFilter()` This filter will be run at least once per descriptor at the point that the descriptor is being looked up, either with the `ServiceLocator` API or due to an @Inject resolution.
`long`	`getThreadInactivityTimeout()` Returns the time in milliseconds a thread will wait for new Immediate services before dying
`Validator`	`getValidator()` Returns the `Validator` that will be run whenever a `Descriptor` that passed the filter is to be looked up with the API or injected into an injection point, or on any bind or unbind operation.
`void`	`onFailure(ErrorInformation errorInformation)` This method is called when a failure occurs in the system.
`void`	`run()` This thread will wait twenty seconds for new work to come in, and then kill itself
`void`	`setExecutor(Executor executor)` Sets the executor to be used by the Immediate subsystem.
`void`	`setImmediateState(ImmediateController.ImmediateServiceState state)` Sets the state the system is currently running under
`void`	`setThreadInactivityTimeout(long timeInMillis)` Sets the time in milliseconds a thread will wait for new Immediate services before dying
`boolean`	`validate(ValidationInformation info)` This method is called whenever it has been determined that a validating class is to be injected into an injection point, or when a descriptor is being looked up explicitly with the API, or a descriptor is being bound or unbound into the registry.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - configurationChanged
```
public void configurationChanged()
```
    Description copied from interface: DynamicConfigurationListener
    
    This method is called when the set of descriptors in this service locator has been changed. Changes to parent service locators descriptors will not be reported. These services are called back on the thread doing the DynamicConfiguration.commit() so care should be taken to do any work quickly. Any exception thrown from this method will be ignored. A commit that failed will not be reported to this method
    
    Specified by:
    
    configurationChanged in interface DynamicConfigurationListener
  - getLookupFilter
```
public Filter getLookupFilter()
```
    Description copied from interface: ValidationService
    
    This filter will be run at least once per descriptor at the point that the descriptor is being looked up, either with the ServiceLocator API or due to an @Inject resolution. The decision made by this filter will be cached and used every time that Descriptor is subsequently looked up. No validation checks should be done in the returned filter, it is purely meant to limit the Descriptors that are passed into the validator.
    Descriptors passed to this filter may or may not be reified. The filter should try as much as possible to do its work without reifying the descriptor.
    The filter may be run more than once on a descriptor if some condition caused the cache of results per descriptor to become invalidated.
    
    Specified by:
    
    getLookupFilter in interface ValidationService
    
    Returns:
    
    The filter to be used to determine if the validators associated with this service should be called when the passed in Descriptor is looked up
  - getValidator
```
public Validator getValidator()
```
    Description copied from interface: ValidationService
    
    Returns the Validator that will be run whenever a Descriptor that passed the filter is to be looked up with the API or injected into an injection point, or on any bind or unbind operation. If this method returns false then the operation will not proceed.
    
    Specified by:
    
    getValidator in interface ValidationService
    
    Returns:
    
    A non-null validator
  - onFailure
```
public void onFailure(ErrorInformation errorInformation)
               throws MultiException
```
    Description copied from interface: ErrorService
    
    This method is called when a failure occurs in the system. This method may use any ServiceLocator api. For example, an implementation of this method might want to remove a descriptor from the registry if the error can be determined to be a permanent failure.
    
    Specified by:
    
    onFailure in interface ErrorService
    
    Parameters:
    
    errorInformation - Information about the error that occurred
    
    Throws:
    
    MultiException - if this method throws an exception that exception will be thrown back to the caller wrapped in another MultiException if the error is of type ErrorType.FAILURE_TO_REIFY. If the error is of type ErrorType.DYNAMIC_CONFIGURATION_FAILURE or ErrorType.SERVICE_CREATION_FAILURE or ErrorType.SERVICE_DESTRUCTION_FAILURE then any exception thrown from this method is ignored and the original exception is thrown back to the caller
  - validate
```
public boolean validate(ValidationInformation info)
```
    Description copied from interface: Validator
    
    This method is called whenever it has been determined that a validating class is to be injected into an injection point, or when a descriptor is being looked up explicitly with the API, or a descriptor is being bound or unbound into the registry.
    The candidate descriptor being passed in may not have yet been reified. If possible, this method should do its work without reifying the descriptor. However, if it is necessary to reify the descriptor, it should be done with the ServiceLocator.reifyDescriptor method.
    The operation will determine what operation is being performed. In the BIND or UNBIND cases the Injectee will be null. In the LOOKUP case the Injectee will be non-null if this is being done as part of an injection point. In the LOOKUP case the Injectee will be null if this is being looked up directly from the ServiceLocator API, in which case the caller of the lookup method will be on the call frame.
    
    Specified by:
    
    validate in interface Validator
    
    Parameters:
    
    info - Information about the operation being performed
    
    Returns:
    
    true if this injection should succeed, false if this candidate should not be returned
  - run
```
public void run()
```
    This thread will wait twenty seconds for new work to come in, and then kill itself
    
    Specified by:
    
    run in interface Runnable
  - getExecutor
```
public Executor getExecutor()
```
    Description copied from interface: ImmediateController
    
    Returns the executor that is currently in use by the Immediate subsystem
    
    Specified by:
    
    getExecutor in interface ImmediateController
    
    Returns:
    
    The current executor in use by the controller. Will not return null since a default executor is used and returned by this call even if setExecutor is called with null
  - setExecutor
```
public void setExecutor(Executor executor)
                 throws IllegalStateException
```
    Description copied from interface: ImmediateController
    
    Sets the executor to be used by the Immediate subsystem. If set to null a default executor will be used. This may only be called when the Immediate service is suspended
    
    Specified by:
    
    setExecutor in interface ImmediateController
    
    Parameters:
    
    executor - The executor to be used when scheduling work. If null a default executor implementation will be used
    
    Throws:
    
    IllegalStateException - if this is called when the Immediate service is not in suspended state
  - getThreadInactivityTimeout
```
public long getThreadInactivityTimeout()
```
    Description copied from interface: ImmediateController
    
    Returns the time in milliseconds a thread will wait for new Immediate services before dying
    
    Specified by:
    
    getThreadInactivityTimeout in interface ImmediateController
    
    Returns:
    
    The time in milliseconds a thread will wait for new Immediate service before dying
  - setThreadInactivityTimeout
```
public void setThreadInactivityTimeout(long timeInMillis)
                                throws IllegalStateException
```
    Description copied from interface: ImmediateController
    
    Sets the time in milliseconds a thread will wait for new Immediate services before dying
    
    Specified by:
    
    setThreadInactivityTimeout in interface ImmediateController
    
    Parameters:
    
    timeInMillis - The time in milliseconds a thread will wait for new Immediate service before dying
    
    Throws:
    
    IllegalStateException
  - getImmediateState
```
public ImmediateController.ImmediateServiceState getImmediateState()
```
    Description copied from interface: ImmediateController
    
    Returns the state the system is currently running under
    
    Specified by:
    
    getImmediateState in interface ImmediateController
    
    Returns:
    
    The current state of the ImmediateService
  - setImmediateState
```
public void setImmediateState(ImmediateController.ImmediateServiceState state)
```
    Description copied from interface: ImmediateController
    
    Sets the state the system is currently running under
    
    Specified by:
    
    setImmediateState in interface ImmediateController
    
    Parameters:
    
    state - The new state of the ImmediateService

Class ImmediateHelper

Nested Class Summary

Nested classes/interfaces inherited from interface org.glassfish.hk2.api.ImmediateController

Method Summary

Methods inherited from class java.lang.Object

Method Detail

configurationChanged

getLookupFilter

getValidator

onFailure

validate

run

getExecutor

setExecutor

getThreadInactivityTimeout

setThreadInactivityTimeout

getImmediateState

setImmediateState