oracle.dbtools.plugin.api.di

Interface InstanceProvider<T>

Type Parameters:

T - The type of the service that was located

All Superinterfaces:

Iterable<T>, javax.inject.Provider<T>, Supplier<T>

All Known Implementing Classes:

DeferredInstanceProvider, ResolvedInstances

public interface InstanceProvider<T>
extends Iterable<T>, javax.inject.Provider<T>, Supplier<T>

Provider specialization that provides the ability to:

• determine if a provider implementation was found, via isUnsatisfied()
• determine if there are multiple implementations found, via isAmbiguous()
• Iterate over the available implementations, via iterator()
• Stream through available implementations, via stream()

Author:

cdivilly

See Also:

InstanceLocator

Method Summary

Modifier and Type	Method and Description
T	get() Retrieve the first available instance
default T	getOrNull() Retrieve the instance or null if no instance is available
boolean	hasMultiple() Determines if there is more than one available implementation for the required type and qualifiers
default boolean	isAmbiguous() Determines if there is more than one available implementation for the required type and qualifiers.
default boolean	isAvailable() Indicates if at least one matching provider is found
default boolean	isUnavailable() Equivalent to isUnsatisfied()
boolean	isUnsatisfied() Determines if there is no available implementation for the required type and qualifiers.
Iterator<T>	iterator() When a service has multiple providers (which can be determined by calling isAmbiguous()) this iterator enumerates each of the available providers
default T	orElse(T value) Retrieve the instance or the specified default value if no instance is available
TypeQualifier<T>	qualifier() Identifies the constraints used to select matches
default Stream<T>	stream() Adapt this set of providers to a Stream instance

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Method Detail

get

T get()

Retrieve the first available instance

Specified by:

get in interface javax.inject.Provider<T>

Specified by:

get in interface Supplier<T>

Returns:

the first available instance

Throws:

TypeDependencyNotAvailableException - if no instance is available

orElse

default T orElse(T value)

Retrieve the instance or the specified default value if no instance is available

Parameters:

value - The default value to provide if no instance is available

Returns:

The first available instance or the provided default value

getOrNull

default T getOrNull()

Retrieve the instance or null if no instance is available

Returns:

The first available instance or null if no instance is available

hasMultiple

boolean hasMultiple()

Determines if there is more than one available implementation for the required type and qualifiers

Returns:

true if there are multiple providers, false otherwise

Since:

19.3.0

isAmbiguous

default boolean isAmbiguous()

Determines if there is more than one available implementation for the required type and qualifiers. Synonym for hasMultiple()

Returns:

true if there are multiple providers, false otherwise

isAvailable

default boolean isAvailable()

Indicates if at least one matching provider is found

Returns:

true if one or more providers is available, false otherwise

Since:

19.3.0

isUnavailable

default boolean isUnavailable()

Equivalent to isUnsatisfied()

Returns:

true if no matching provider is available, false otherwise

Since:

19.3.0

isUnsatisfied

boolean isUnsatisfied()

Determines if there is no available implementation for the required type and qualifiers. If this method returns true, then calling get() will raise a RuntimeException

Returns:

true if there is no provider, false otherwise

iterator

Iterator<T> iterator()

When a service has multiple providers (which can be determined by calling isAmbiguous()) this iterator enumerates each of the available providers

Specified by:

iterator in interface Iterable<T>

Returns:

The set of available providers

stream

default Stream<T> stream()

Adapt this set of providers to a Stream instance

Returns:

Stream of provider instances

Since:

20.3.0

qualifier

TypeQualifier<T> qualifier()

Identifies the constraints used to select matches

Returns:

TypeQualifier instance

Since:

19.3.0