Module io.helidon.config

Package io.helidon.config

Class FileConfigSource

java.lang.Object

io.helidon.config.AbstractSource

io.helidon.config.AbstractConfigSource

io.helidon.config.FileConfigSource

All Implemented Interfaces:

ConfigSource, ParsableSource, PollableSource<byte[]>, Source, WatchableSource<Path>, Supplier<ConfigSource>

public class FileConfigSource
extends AbstractConfigSource
implements WatchableSource<Path>, ParsableSource, PollableSource<byte[]>

ConfigSource implementation that loads configuration content from a file on a filesystem.

See Also:

• FileConfigSource.Builder

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	FileConfigSource.Builder	File ConfigSource Builder.

Method Summary

Modifier and Type	Method	Description
static FileConfigSource.Builder	builder()	Get a builder instance to create a new config source.
Optional<ChangeWatcher<Object>>	changeWatcher()	A change watcher of this source, if it implements WatchableSource and has one configured.
static FileConfigSource	create(Config metaConfig)	Initializes config source instance from configuration properties.
boolean	exists()	If the underlying data exist at this time.
boolean	isModified(byte[] stamp)	This method is invoked to check if this source has changed.
Optional<ConfigParser.Content>	load()	Loads the underlying source data.
Optional<MediaType>	mediaType()	Media type if on eis configured for parsing content of ParsableSource.
Optional<ConfigParser>	parser()	Config parser if one is configured to use for parsing content of ParsableSource.
Optional<PollingStrategy>	pollingStrategy()	A polling strategy of this source, if it implements PollableSource and has one configured.
Function<String,Optional<InputStream>>	relativeResolver()	Resolve relative resource to the current resource.
Path	target()	The target of this source.
protected String	uid()	Returns universal id of source to be used to construct AbstractSource.description().

Methods inherited from class io.helidon.config.AbstractConfigSource

toString

Methods inherited from class io.helidon.config.AbstractSource

description, optional, retryPolicy

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface io.helidon.config.spi.ConfigSource

get, init

Methods inherited from interface io.helidon.config.spi.Source

description, optional, retryPolicy

Methods inherited from interface io.helidon.config.spi.WatchableSource

targetType

Method Details

create

public static FileConfigSource create(Config metaConfig)
                               throws ConfigMappingException,
MissingValueException

Initializes config source instance from configuration properties.

Mandatory properties, see ConfigSources.file(String):

• path - type Path

Optional properties: see AbstractConfigSourceBuilder.config(Config).

Parameters:

metaConfig - meta-configuration used to initialize returned config source instance from.

Returns:

new instance of config source described by metaConfig

Throws:

MissingValueException - in case the configuration tree does not contain all expected sub-nodes required by the mapper implementation to provide instance of Java type.

ConfigMappingException - in case the mapper fails to map the (existing) configuration tree represented by the supplied configuration node to an instance of a given Java type.

See Also:

• ConfigSources.file(String)
• AbstractConfigSourceBuilder.config(Config)

builder

public static FileConfigSource.Builder builder()

Get a builder instance to create a new config source.

Returns:

a fluent API builder

uid

protected String uid()

Description copied from class: AbstractSource

Returns universal id of source to be used to construct AbstractSource.description().

Overrides:

uid in class AbstractSource

Returns:

universal id of source

isModified

public boolean isModified(byte[] stamp)

Description copied from interface: PollableSource

This method is invoked to check if this source has changed.

Specified by:

isModified in interface PollableSource<byte[]>

Parameters:

stamp - the stamp of the last loaded content

Returns:

true if the current data of this config source differ from the loaded data, including cases when the source has disappeared

target

public Path target()

Description copied from interface: WatchableSource

The target of this source.

Specified by:

target in interface WatchableSource<Path>

Returns:

target this source is configured with, never null

load

public Optional<ConfigParser.Content> load()
                                    throws ConfigException

Description copied from interface: ParsableSource

Loads the underlying source data. This method is only called when the source Source.exists().

The method can be invoked repeatedly, for example during retries. In case the underlying data is gone or does not exist, return an empty optional.

Specified by:

load in interface ParsableSource

Returns:

An instance of T as read from the underlying origin of the data (if it exists)

Throws:

ConfigException - in case of errors loading from the underlying origin

relativeResolver

public Function<String,Optional<InputStream>> relativeResolver()

Description copied from interface: ParsableSource

Resolve relative resource to the current resource.

Specified by:

relativeResolver in interface ParsableSource

Returns:

a function to resolve resource name into an input stream

parser

public Optional<ConfigParser> parser()

Description copied from class: AbstractConfigSource

Config parser if one is configured to use for parsing content of ParsableSource. If one is not configured on a source (default), a parser is chosen based on AbstractConfigSource.mediaType().

Specified by:

parser in interface ParsableSource

Overrides:

parser in class AbstractConfigSource

Returns:

a configured parser, or empty if one should be chosen from media type (or if this is not a parsable source)

mediaType

public Optional<MediaType> mediaType()

Description copied from class: AbstractConfigSource

Media type if on eis configured for parsing content of ParsableSource. If there is none configured (default), a parser is chosen based on ConfigParser.Content.mediaType() - media type detected during load of data.

Specified by:

mediaType in interface ParsableSource

Overrides:

mediaType in class AbstractConfigSource

Returns:

configured media type or empty if none configured

pollingStrategy

public Optional<PollingStrategy> pollingStrategy()

Description copied from class: AbstractSource

A polling strategy of this source, if it implements PollableSource and has one configured.

Specified by:

pollingStrategy in interface PollableSource<byte[]>

Overrides:

pollingStrategy in class AbstractSource

Returns:

polling strategy if any configured

changeWatcher

public Optional<ChangeWatcher<Object>> changeWatcher()

Description copied from class: AbstractSource

A change watcher of this source, if it implements WatchableSource and has one configured.

Specified by:

changeWatcher in interface WatchableSource<Path>

Overrides:

changeWatcher in class AbstractSource

Returns:

change watcher if any configured

exists

public boolean exists()

Description copied from interface: Source

If the underlying data exist at this time. This is to prevent us loading such a source if we know it does not exist.

Specified by:

exists in interface Source

Returns:

true if the source exists, false otherwise