Package io.helidon.config

Class ConfigSources.CompositeBuilder

java.lang.Object

io.helidon.config.ConfigSources.CompositeBuilder

All Implemented Interfaces:

Builder<ConfigSource>, Supplier<ConfigSource>

Enclosing class:

ConfigSources

public static class ConfigSources.CompositeBuilder
extends Object
implements Builder<ConfigSource>

Builder of a ConfigSource that encapsulates multiple separate ConfigSources.

The caller invokes add(java.util.function.Supplier<io.helidon.config.spi.ConfigSource>) one or more times to assemble an ordered list of ConfigSources to be combined. The build() and get() methods return a single ConfigSource that combines the ordered sequence of ConfigSources using a merging strategy (by default, the fallback merging strategy). The caller can change the merging strategy by passing an alternative strategy to the mergingStrategy method.

The CompositeBuilder also supports change monitoring. The application can control these aspects:

Application Control of Change Monitoring

Change Support Behavior	Use	Method
reload executor	The executor used to reload the configuration upon detection of a change in the underlying ConfigSource	changesExecutor(java.util.concurrent.ScheduledExecutorService)
debounce timeout	Minimum delay between reloads - helps reduce multiple reloads due to multiple changes in a short period, collecting a group of changes into one notification	changesDebounce(java.time.Duration)
buffer size	Maximum number of changes allowed in the change flow	changesMaxBuffer(int)

See Also:

ConfigSources.create(Supplier...), ConfigSources.MergingStrategy, default merging strategy

Method Summary

Modifier and Type	Method	Description
ConfigSources.CompositeBuilder	add(Supplier<ConfigSource> source)	Adds a ConfigSource to the ordered list of sources.
ConfigSource	build()	Builds new instance of Composite ConfigSource.
ConfigSources.CompositeBuilder	changesDebounce(Duration debounceTimeout)	Specifies debounce timeout for reloading the config after the underlying config source(s) change.
ConfigSources.CompositeBuilder	changesExecutor(ScheduledExecutorService changesExecutor)	Specifies ScheduledExecutorService on which reloads of the config source will occur.
ConfigSources.CompositeBuilder	changesMaxBuffer(int changesMaxBuffer)	Specifies maximum capacity for each subscriber's buffer to be used to deliver config source changes.
ConfigSource	get()
ConfigSources.CompositeBuilder	mergingStrategy(ConfigSources.MergingStrategy mergingStrategy)	Sets the strategy to be used for merging the root nodes provided by the list of ConfigSources.

Methods inherited from class java.lang.Object

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

Method Detail

add

public ConfigSources.CompositeBuilder add(Supplier<ConfigSource> source)

Adds a ConfigSource to the ordered list of sources.

Parameters:

source - config source

Returns:

updated builder

mergingStrategy

public ConfigSources.CompositeBuilder mergingStrategy(ConfigSources.MergingStrategy mergingStrategy)

Sets the strategy to be used for merging the root nodes provided by the list of ConfigSources.

Parameters:

mergingStrategy - strategy for merging root nodes from the config sources

Returns:

updated builder

See Also:

ConfigSources.MergingStrategy.fallback()

changesExecutor

public ConfigSources.CompositeBuilder changesExecutor(ScheduledExecutorService changesExecutor)

Specifies ScheduledExecutorService on which reloads of the config source will occur.

By default, a dedicated thread pool that can schedule reload commands to run after a given timeout is used.

Parameters:

changesExecutor - the executor used for scheduling config source reloads

Returns:

updated builder

See Also:

changesDebounce(Duration)

changesDebounce

public ConfigSources.CompositeBuilder changesDebounce(Duration debounceTimeout)

Specifies debounce timeout for reloading the config after the underlying config source(s) change.

Debouncing reduces the number of change events by collecting any changes over the debounce timeout interval into a single event.

The default is 100 milliseconds.

Parameters:

debounceTimeout - debounce timeout to process reloading

Returns:

modified builder instance

See Also:

changesExecutor(ScheduledExecutorService)

changesMaxBuffer

public ConfigSources.CompositeBuilder changesMaxBuffer(int changesMaxBuffer)

Specifies maximum capacity for each subscriber's buffer to be used to deliver config source changes.

By default Flow.defaultBufferSize() is used.

Note: Any events not consumed by a subscriber will be lost.

Parameters:

changesMaxBuffer - the maximum capacity for each subscriber's buffer of Source.changes() events.

Returns:

modified builder instance

See Also:

changesExecutor(ScheduledExecutorService), Source.changes()

build

public ConfigSource build()

Builds new instance of Composite ConfigSource.

Specified by:

build in interface Builder<ConfigSource>

Returns:

new instance of Composite ConfigSource.

get

public ConfigSource get()

Specified by:

get in interface Builder<ConfigSource>

Specified by:

get in interface Supplier<ConfigSource>