Package io.helidon.config.spi

Interface Source<T>

Type Parameters:

T - a type of source

All Superinterfaces:

AutoCloseable, Changeable<T>

All Known Subinterfaces:

ConfigSource, OverrideSource

All Known Implementing Classes:

AbstractConfigSource, AbstractOverrideSource, AbstractParsableConfigSource, AbstractSource, EtcdConfigSource, GitConfigSource

public interface Source<T>
extends Changeable<T>, AutoCloseable

Source of the specified type <T> of data.

Method Summary

Modifier and Type	Method	Description
default Flow.Publisher<Optional<T>>	changes()	Deprecated.
default void	close()	Closes the @{code Source}, releasing any resources it holds.
default String	description()	Short, human-readable summary referring to the underlying source.
Optional<T>	load()	Loads the underlying source data, converting it into an Optional around the parameterized type T.

Method Detail

description

default String description()

Short, human-readable summary referring to the underlying source.

For example, a file path or a URL or any other information that helps the user recognize the underlying origin of the data this Source provides.

Default is the implementation class simple name with any "Source" suffix removed.

Returns:

description of the source

load

Optional<T> load()
          throws ConfigException

Loads the underlying source data, converting it into an Optional around the parameterized type T.

Implementations should return Optional.empty() if the underlying origin does not exist.

The method can be invoked repeatedly, for example during retries.

Returns:

Optional<T> referring to an instance of T as read from the underlying origin of the data (if it exists) or Optional.empty() otherwise

Throws:

ConfigException - in case of errors loading from the underlying origin

changes

@Deprecated
default Flow.Publisher<Optional<T>> changes()

Deprecated.

Description copied from interface: Changeable

Returns a Flow.Publisher to which the caller can subscribe in order to receive change notifications.

Method Flow.Subscriber.onError(Throwable) is called in case of error listening on config source data. Method Flow.Subscriber.onComplete() is never called.

Specified by:

changes in interface Changeable<T>

Returns:

a publisher of events. Never returns null

close

default void close()
            throws Exception

Closes the @{code Source}, releasing any resources it holds.

Specified by:

close in interface AutoCloseable

Throws:

Exception - in case of errors encountered while closing the source