Module io.helidon.config

Package io.helidon.config.spi

Configuration SPI that defines the behavior developers can implement to extend the config system.

The most likely developer-implemented extension points:

Common Extension Points

Interface	Purpose
ConfigSource	Loads configuration data from a type of source.
ConfigParser	Converts configuration data into a ConfigNode.ObjectNode.
ConfigFilter	Filters configuration values after they have been read from a ConfigSource but before they are used in building a Config tree.
ConfigMapperProvider	Converts Config nodes or subtrees to Java types. See ConfigMappers for the built-in mappers.
OverrideSource	Replaces values pf config nodes whose keys match specified conditions with alternative values.
PollingStrategy	Notifies interested code when the data underlying a Source might have changed.
RetryPolicy	Controls if and how a Source attempts to retry failed attempts to load the underlying data.

See Also:

Configuration API

Interface Summary

Interface	Description
ChangeWatcher<T>	Similar to a PollingStrategy a change watcher is used to identify a change and trigger reload of a ConfigSource.
ChangeWatcher.ChangeEvent<T>	A change event, carrying the target, type of change and time of change.
ChangeWatcherProvider	Java service loader service to create a polling strategy factory based on meta configuration.
ConfigContent	Config content as provided by a config source that can read all its data at once (an "eager" config source).
ConfigContent.NodeContent	Config content that provides an ConfigNode.ObjectNode directly, with no need for parsing.
ConfigContent.OverrideContent	A content of an OverrideSource.
ConfigContext	Context created by a Config.Builder as it constructs a Config.
ConfigFilter	Filter that can transform elementary configuration (String) values before they are returned via the Config API.
ConfigMapper	Config mapper is provided to ConfigMapperProvider to help transformation of complex structures.
ConfigMapperProvider	Provides mapping functions that convert a Config subtree to specific Java types.
ConfigNode	Marker interface identifying a config node implementation.
ConfigNode.ListNode	ConfigNode-based list of configuration values.
ConfigNode.ListNode.Builder	Builder to build ConfigNode.ListNode instance.
ConfigNode.ObjectNode	Configuration node representing a hierarchical structure parsed by a suitable ConfigParser if necessary.
ConfigNode.ObjectNode.Builder	Builder to build ConfigNode.ObjectNode instance.
ConfigNode.ValueNode	Single string-based configuration value.
ConfigParser	Transforms config ConfigParser.Content into a ConfigNode.ObjectNode that represents the original structure and values from the content.
ConfigParser.Content	Config content to be parsed by a ConfigParser.
ConfigSource	Source of configuration.
ConfigSourceProvider	Java service loader service to provide a config source based on meta configuration.
EventConfigSource	A source that supports notifications when changed.
LazyConfigSource	A source that is not capable of loading all keys at once.
MergingStrategy	An algorithm for combining multiple ConfigNode.ObjectNode root nodes into a single ConfigNode.ObjectNode root node.
NodeConfigSource	An eager source that can read all data from the underlying origin as a configuration node.
OverrideSource	Source of config override settings.
OverrideSourceProvider	Java service loader service to provide a override source based on meta configuration.
ParsableSource	An eager source that can read all data from the underlying origin as a stream that can be parsed based on its media type (or using an explicit ConfigParser.
ParsableSource.Builder<B extends ParsableSource.Builder<B>>	A builder for a parsable source.
PollableSource<S>	A source implementing this interface provides support for polling using a PollingStrategy.
PollableSource.Builder<T extends PollableSource.Builder<T>>	A builder for pollable source.
PollingStrategy	Mechanism for notifying interested listeners when they should check for changes that might have been made to the data used to create a Config tree, as accessed through PollableSources.
PollingStrategy.Polled	A polled component.
PollingStrategyProvider	Java service loader service to create a polling strategy factory based on meta configuration.
RetryPolicy	Mechanism for controlling retry of attempts to load data by a ConfigSource.
RetryPolicyProvider	Java service loader service to create retry policy based on meta configuration.
Source	Source of data.
Source.Builder<B extends Source.Builder<B>>	Configurable options of a Source.
WatchableSource<T>	A source implementing this interface provides a target that a ChangeWatcher can use.
WatchableSource.Builder<B extends WatchableSource.Builder<B,T>,T>	A builder for a watchable source.

Class Summary

Class	Description
ConfigContent.Builder<T extends ConfigContent.Builder<T>>	Fluent API builder for ConfigContent, common ancestor for parsable content builder and node content builder.
ConfigContent.NodeContent.Builder	Fluent API builder for ConfigContent.NodeContent.
ConfigContent.OverrideContent.Builder
ConfigParser.Content.Builder	Fluent API builder for ConfigParser.Content.
OverrideSource.OverrideData	Group of config override settings.

Enum Summary

Enum	Description
ChangeEventType	Type of changes that can happen in a PollingStrategy.Polled components.
ConfigNode.NodeType	Base types of config nodes.

Exception Summary

Exception	Description
ConfigParserException	Root class for exceptions thrown during config parsing.