Modifier and Type	Class and Description
private static class	ServiceProvider.Selector A filter and a comparator for processing the stream of service providers.

Modifier and Type	Field and Description
private static final AtomicReference<ServiceProvider>	current The current service provider, or `null` if not yet determined.
private static final String	LEGACY_NAMED_ANNOTATION Class name of JSR-330 annotation for naming a service provider.
private static final String	LEGACY_PRIORITY_ANNOTATION Class name of JSR-250 annotation for assigning a priority level to a service provider.
private static final String	NAMED_ANNOTATION Class name of Jakarta Dependency Injection annotation for naming a service provider.
private static final String	PRIORITY_ANNOTATION Class name of Jakarta Common Annotation for assigning a priority level to a service provider.

Access	Constructor and Description
protected	ServiceProvider() Creates a new service provider.

Method Summary

Modifier and Type	Method and Description
public static final List<ServiceProvider>	Returns: all service providers available for the current thread's context class loader. available() Returns the list of all service providers available for the current thread's context class loader.
public static final ServiceProvider	Returns: the `ServiceProvider` used. current() Returns the current `ServiceProvider`.
public abstract FormatService	Returns: the service to obtain a `UnitFormat` and `QuantityFormat`, or `null`. getFormatService() Returns the service to obtain `UnitFormat` and `QuantityFormat` or `null` if none.
public int	Returns: the provider's priority (default is 0). getPriority() Allows to define a priority for a registered `ServiceProvider` instance.
public abstract < the type of the `Quantity` instances created by the factory Q extends Quantity<Q>> QuantityFactory<Q>	Returns: the `QuantityFactory` for the given type getQuantityFactory(Class<Q> the quantity type quantity) Returns a factory for the given `Quantity` type.
public abstract SystemOfUnitsService	Returns: the service to obtain a `SystemOfUnits`, or `null`. getSystemOfUnitsService() Returns the service to obtain a `SystemOfUnits`, or `null` if none.
public static ServiceProvider	Returns: the `ServiceProvider` with the specified name of(String the name of the service provider to return name) Returns the `ServiceProvider` with the specified name.
public static final ServiceProvider	Returns: the replaced provider, or null. setCurrent(ServiceProvider the new `ServiceProvider` provider) Replaces the current `ServiceProvider`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

current back to summary

current	back to summary
private static final AtomicReference<ServiceProvider> current The current service provider, or `null` if not yet determined. Implementation Note We do not cache a list of all service providers because that list depends indirectly on the thread invoking the `available()` method. More specifically, it depends on the context class loader. Furthermore caching the `ServiceProvider`s can be a source of memory leaks. See `ServiceLoader#load(Class)` API note for reference.

private static final AtomicReference<ServiceProvider> current

The current service provider, or null if not yet determined.

Implementation Note

We do not cache a list of all service providers because that list depends indirectly on the thread invoking the available() method. More specifically, it depends on the context class loader. Furthermore caching the ServiceProviders can be a source of memory leaks. See ServiceLoader#load(Class) API note for reference.

LEGACY_NAMED_ANNOTATION	back to summary
private static final String LEGACY_NAMED_ANNOTATION Class name of JSR-330 annotation for naming a service provider. We use reflection for keeping JSR-330 an optional dependency.

LEGACY_PRIORITY_ANNOTATION	back to summary
private static final String LEGACY_PRIORITY_ANNOTATION Class name of JSR-250 annotation for assigning a priority level to a service provider. We use reflection for keeping JSR-250 an optional dependency.

NAMED_ANNOTATION	back to summary
private static final String NAMED_ANNOTATION Class name of Jakarta Dependency Injection annotation for naming a service provider. We use reflection for keeping Jakata Injection an optional dependency.

PRIORITY_ANNOTATION	back to summary
private static final String PRIORITY_ANNOTATION Class name of Jakarta Common Annotation for assigning a priority level to a service provider. We use reflection for keeping Jakarta Annotations an optional dependency.

ServiceProvider	back to summary
protected ServiceProvider() Creates a new service provider. Only to be used by subclasses.

Method Detail

available	back to summary
public static final List<ServiceProvider> available() Returns the list of all service providers available for the current thread's context class loader. The current service provider is always the first item in the returned list. Other service providers after the first item may depend on the caller thread (see service loader API note). Returns:List<ServiceProvider> all service providers available for the current thread's context class loader.

available

back to summary

public static final List<ServiceProvider> available()

Returns the list of all service providers available for the current thread's context class loader. The current service provider is always the first item in the returned list. Other service providers after the first item may depend on the caller thread (see service loader API note).

Returns:List<ServiceProvider>: all service providers available for the current thread's context class loader.

current back to summary

current	back to summary
public static final ServiceProvider current() Returns the current `ServiceProvider`. If necessary the `ServiceProvider` will be lazily loaded. If there are no providers available, an IllegalStateException is thrown. Otherwise the provider with the highest priority is used or the one explicitly designated via `setCurrent(ServiceProvider)`. Returns:ServiceProvider the `ServiceProvider` used. Exceptions IllegalStateException: if no `ServiceProvider` has been found. See Also `getPriority()`, `setCurrent(ServiceProvider)`

public static final ServiceProvider current()

Returns the current ServiceProvider. If necessary the ServiceProvider will be lazily loaded.

If there are no providers available, an IllegalStateException is thrown. Otherwise the provider with the highest priority is used or the one explicitly designated via setCurrent(ServiceProvider).

Returns:ServiceProvider

the ServiceProvider used.

Exceptions

IllegalStateException:: if no ServiceProvider has been found.

getFormatService back to summary

getFormatService	back to summary
public abstract FormatService getFormatService() Returns the service to obtain `UnitFormat` and `QuantityFormat` or `null` if none. Returns:FormatService the service to obtain a `UnitFormat` and `QuantityFormat`, or `null`. Since 2.0

public abstract FormatService getFormatService()

Returns the service to obtain UnitFormat and QuantityFormat or null if none.

Returns:FormatService: the service to obtain a UnitFormat and QuantityFormat, or null.
Since: 2.0

getPriority back to summary

getPriority	back to summary
public int getPriority() Allows to define a priority for a registered `ServiceProvider` instance. When multiple providers are registered in the system, the provider with the highest priority value is taken. If the jakarta.annotation.Priority annotation (from Jakarta Annotations) or javax.annotation.Priority annotation (from JSR-250) is present on the `ServiceProvider` implementation class, then that annotation (first if both were present) is taken and this `getPriority()` method is ignored. Otherwise – if a `Priority` annotation is absent – this method is used as a fallback. Returns:int the provider's priority (default is 0).

public int getPriority()

Allows to define a priority for a registered ServiceProvider instance. When multiple providers are registered in the system, the provider with the highest priority value is taken.

If the jakarta.annotation.Priority annotation (from Jakarta Annotations) or javax.annotation.Priority annotation (from JSR-250) is present on the ServiceProvider implementation class, then that annotation (first if both were present) is taken and this getPriority() method is ignored. Otherwise – if a Priority annotation is absent – this method is used as a fallback.

Returns:int: the provider's priority (default is 0).

getQuantityFactory back to summary

getQuantityFactory	back to summary
public abstract <Q extends Quantity<Q>> QuantityFactory<Q> getQuantityFactory(Class<Q> quantity) Returns a factory for the given `Quantity` type. Parameters <Q> the type of the `Quantity` instances created by the factory quantity:Class<Q> the quantity type Returns:QuantityFactory<Q> the `QuantityFactory` for the given type

public abstract <Q extends Quantity<Q>> QuantityFactory<Q> getQuantityFactory(Class<Q> quantity)

Returns a factory for the given Quantity type.

Parameters

<Q>: the type of the Quantity instances created by the factory
quantity:Class<Q>: the quantity type

Returns:QuantityFactory<Q>

the QuantityFactory for the given type

getSystemOfUnitsService back to summary

getSystemOfUnitsService	back to summary
public abstract SystemOfUnitsService getSystemOfUnitsService() Returns the service to obtain a `SystemOfUnits`, or `null` if none. Returns:SystemOfUnitsService the service to obtain a `SystemOfUnits`, or `null`.

public abstract SystemOfUnitsService getSystemOfUnitsService()

Returns the service to obtain a SystemOfUnits, or null if none.

Returns:SystemOfUnitsService: the service to obtain a SystemOfUnits, or null.

of back to summary

of	back to summary
public static ServiceProvider of(String name) Returns the `ServiceProvider` with the specified name. The given name must match the name of at least one service provider available in the current thread's context class loader. The service provider names are the values of jakarta.inject.Named (from Jakarta Annotations) or javax.inject.Named (from JSR-330) annotations when present (first if both were present), or the value of `toString()` method for providers without `Named` annotation. Implementors are encouraged to provide an `Named` annotation or to override `toString()` and use a unique enough name, e.g. the class name or other distinct attributes. Should multiple service providers nevertheless use the same name, the one with the highest priority wins. Parameters name:String the name of the service provider to return Returns:ServiceProvider the `ServiceProvider` with the specified name Exceptions IllegalArgumentException: if available service providers do not contain a provider with the specified name NullPointerException: if `name` is null Since 2.0 See Also `toString()`

public static ServiceProvider of(String name)

Returns the ServiceProvider with the specified name. The given name must match the name of at least one service provider available in the current thread's context class loader. The service provider names are the values of jakarta.inject.Named (from Jakarta Annotations) or javax.inject.Named (from JSR-330) annotations when present (first if both were present), or the value of toString() method for providers without Named annotation.

Implementors are encouraged to provide an Named annotation or to override toString() and use a unique enough name, e.g. the class name or other distinct attributes. Should multiple service providers nevertheless use the same name, the one with the highest priority wins.

Parameters

name:String: the name of the service provider to return

Returns:ServiceProvider

the ServiceProvider with the specified name

Exceptions

IllegalArgumentException:: if available service providers do not contain a provider with the specified name
NullPointerException:: if name is null

Since

2.0

See Also

toString()

setCurrent back to summary

setCurrent	back to summary
public static final ServiceProvider setCurrent(ServiceProvider provider) Replaces the current `ServiceProvider`. Parameters provider:ServiceProvider the new `ServiceProvider` Returns:ServiceProvider the replaced provider, or null.

public static final ServiceProvider setCurrent(ServiceProvider provider)

Replaces the current ServiceProvider.

Parameters

provider:ServiceProvider: the new ServiceProvider

Returns:ServiceProvider

the replaced provider, or null.

javax.measure.spi back to summary

private final Class ServiceProvider.Selector

Class Inheritance

extends Object
implements Predicate<ServiceProvider>, Comparator<ServiceProvider>

java.lang.Object
javax.measure.spi.ServiceProvider.Selector

All Implemented Interfaces

java.util.Comparator, java.util.function.Predicate

A filter and a comparator for processing the stream of service providers. The two tasks (filtering and sorting) are implemented by the same class, but the filter task shall be used only if the name to search is non-null. The comparator is used in all cases, for sorting providers with higher priority first.

Field Summary

Modifier and Type	Field and Description
private final Method	legacyNameGetter The `value()` method in the javax.inject.Named annotation, or `null` if that class is not on the classpath.
private final Method	legacyPriorityGetter The `value()` method in the javax.annotation.Priority annotation, or `null` if that class is not on the classpath.
private final Method	nameGetter The `value()` method in the jakarta.inject.Named annotation, or `null` if that class is not on the classpath.
private final Method	priorityGetter The `value()` method in the jakarta.annotation.Priority annotation, or `null` if that class is not on the classpath.
private final String	toSearch The name of the provider to search, or `null` if no filtering by name is applied.

Constructor Summary

Access	Constructor and Description
pack-priv	Selector(String name of the desired service provider, or `null` if no filtering by name is applied. name) Creates a new filter and comparator for a stream of service providers.

Method Summary

Modifier and Type	Method and Description
public int	compare(final ServiceProvider the first object to be compared. p1, final ServiceProvider the second object to be compared. p2) Implements java.util.Comparator.compare. Compares the given service providers for order based on their priority.
private static Object	Returns: the value, or `null` if none. getValue(final Class<?> class of the provider on which to invoke annotation `value()`. provider, Method the preferred `value()` method to invoke, or `null`. getter, Method an alternative `value()` method to invoke, or `null`. fallback) Invokes the `value()` method on the annotation of the given class.
private static Method	Returns: the `value()` method, or `null` if the annotation class was not found. getValueMethod(final String name of the class from which to get the `value()` method. classname) Returns the `value()` method in the given annotation class.
private int	priority(final ServiceProvider provider) Returns the priority of the given service provider.
private Stream<ServiceProvider>	stream() Gets all `ServiceProvider`s sorted by priority and optionally filtered by the name in this selector.
public boolean	test(final ServiceProvider the input argument provider) Implements java.util.function.Predicate.test. Returns `true` if the given service provider has the name we are looking for.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

legacyNameGetter	back to summary
private final Method legacyNameGetter The `value()` method in the javax.inject.Named annotation, or `null` if that class is not on the classpath.

legacyPriorityGetter	back to summary
private final Method legacyPriorityGetter The `value()` method in the javax.annotation.Priority annotation, or `null` if that class is not on the classpath.

nameGetter	back to summary
private final Method nameGetter The `value()` method in the jakarta.inject.Named annotation, or `null` if that class is not on the classpath.

priorityGetter	back to summary
private final Method priorityGetter The `value()` method in the jakarta.annotation.Priority annotation, or `null` if that class is not on the classpath.

toSearch	back to summary
private final String toSearch The name of the provider to search, or `null` if no filtering by name is applied.

Constructor Detail

Selector back to summary

Selector	back to summary
pack-priv Selector(String name) Creates a new filter and comparator for a stream of service providers. Parameters name:String name of the desired service provider, or `null` if no filtering by name is applied.

pack-priv Selector(String name)

Creates a new filter and comparator for a stream of service providers.

Parameters

name:String: name of the desired service provider, or null if no filtering by name is applied.

Method Detail

compare back to summary

compare	back to summary
public int compare(final ServiceProvider p1, final ServiceProvider p2) Implements java.util.Comparator.compare. Compares the given service providers for order based on their priority. The priority of each provider is determined as documented by `ServiceProvider#getPriority()`. Parameters p1:ServiceProvider Doc from java.util.Comparator.compare. the first object to be compared. p2:ServiceProvider Doc from java.util.Comparator.compare. the second object to be compared. Returns:int Doc from java.util.Comparator.compare. a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second. Annotations @Override

public int compare(final ServiceProvider p1, final ServiceProvider p2)

Implements java.util.Comparator.compare.

Compares the given service providers for order based on their priority. The priority of each provider is determined as documented by ServiceProvider#getPriority().

Parameters

p1:ServiceProvider

Doc from java.util.Comparator.compare.

the first object to be compared.

p2:ServiceProvider

Doc from java.util.Comparator.compare.

the second object to be compared.

Returns:int

Doc from java.util.Comparator.compare.

a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

Annotations

@Override

getValue back to summary

getValue	back to summary
private static Object getValue(final Class<?> provider, Method getter, Method fallback) Invokes the `value()` method on the annotation of the given class. The annotation on which to invoke the method is given by `Method#getDeclaringClass()`. Parameters provider:Class<?> class of the provider on which to invoke annotation `value()`. getter:Method the preferred `value()` method to invoke, or `null`. fallback:Method an alternative `value()` method to invoke, or `null`. Returns:Object the value, or `null` if none.

private static Object getValue(final Class<?> provider, Method getter, Method fallback)

Invokes the value() method on the annotation of the given class. The annotation on which to invoke the method is given by Method#getDeclaringClass().

Parameters

provider:Class<?>: class of the provider on which to invoke annotation value().
getter:Method: the preferred value() method to invoke, or null.
fallback:Method: an alternative value() method to invoke, or null.

Returns:Object

the value, or null if none.

getValueMethod back to summary

getValueMethod	back to summary
private static Method getValueMethod(final String classname) throws NoSuchMethodException Returns the `value()` method in the given annotation class. Parameters classname:String name of the class from which to get the `value()` method. Returns:Method the `value()` method, or `null` if the annotation class was not found.

private static Method getValueMethod(final String classname) throws NoSuchMethodException

Returns the value() method in the given annotation class.

Parameters

classname:String: name of the class from which to get the value() method.

Returns:Method

the value() method, or null if the annotation class was not found.

priority	back to summary
private int priority(final ServiceProvider provider) Returns the priority of the given service provider. This method looks for the jakarta.annotation.Priority and javax.annotation.Priority annotations in that order, and if none are found falls back on `ServiceProvider#getPriority()`.

stream	back to summary
private Stream<ServiceProvider> stream() Gets all `ServiceProvider`s sorted by priority and optionally filtered by the name in this selector. The list of service providers is not cached because it depends on the context class loader, which itself depends on which thread is invoking this method.

test back to summary

test	back to summary
public boolean test(final ServiceProvider provider) Implements java.util.function.Predicate.test. Returns `true` if the given service provider has the name we are looking for. This method shall be invoked only if a non-null name has been specified to the constructor. This method looks for the jakarta.inject.Named and javax.inject.Named annotations in that order, and if none are found fallbacks on `ServiceProvider#toString()`. Parameters provider:ServiceProvider Doc from java.util.function.Predicate.test. the input argument Returns:boolean Doc from java.util.function.Predicate.test. `true` if the input argument matches the predicate, otherwise `false` Annotations @Override

public boolean test(final ServiceProvider provider)

Implements java.util.function.Predicate.test.

Returns true if the given service provider has the name we are looking for. This method shall be invoked only if a non-null name has been specified to the constructor. This method looks for the jakarta.inject.Named and javax.inject.Named annotations in that order, and if none are found fallbacks on ServiceProvider#toString().

Parameters

provider:ServiceProvider

Doc from java.util.function.Predicate.test.

the input argument

Returns:boolean

Doc from java.util.function.Predicate.test.

true if the input argument matches the predicate, otherwise false

Annotations

@Override

public abstract Class ServiceProvider

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private final Class ServiceProvider.Selector

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail