Package io.helidon.config.spi

Class AbstractSource.Builder<B extends AbstractSource.Builder<B,T,S>,T,S>

java.lang.Object

io.helidon.config.spi.AbstractSource.Builder<B,T,S>

Type Parameters:

B - type of Builder implementation

T - type of key source attributes (target) used to construct polling strategy from

S - type of source that should be built

Direct Known Subclasses:

AbstractConfigSource.Builder, AbstractOverrideSource.Builder

Enclosing class:

AbstractSource<T,S>

public abstract static class AbstractSource.Builder<B extends AbstractSource.Builder<B,T,S>,T,S>
extends Object

A common AbstractSource builder, suitable for concrete Builder implementations related to AbstractSource extensions to extend.

The application can control this behavior:

• mandatory - whether the resource is mandatory (by default) or optional
• pollingStrategy - which source reload policy to use
• changes executor and subscriber's buffer size - related to propagating source changes

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Builder(Class<T> targetType)	Initializes builder.

Method Summary

Modifier and Type	Method	Description
abstract S	build()	Builds new instance of S.
protected Executor	changesExecutor()	Returns changes-executor property.
B	changesExecutor(Executor changesExecutor)	Specifies "observe-on" Executor to be used to deliver config source changes.
protected int	changesMaxBuffer()	Returns changes-max-buffer property.
B	changesMaxBuffer(int changesMaxBuffer)	Specifies maximum capacity for each subscriber's buffer to be used to deliver config source changes.
protected B	init(Config metaConfig)	Initialize builder from specified configuration properties.
protected boolean	isMandatory()	Returns mandatory property.
B	optional()	Built ConfigSource will not be mandatory, i.e.
protected PollingStrategy	pollingStrategy()	Returns polling-strategy property.
B	pollingStrategy(Function<T,Supplier<PollingStrategy>> pollingStrategyProvider)	Sets the polling strategy that accepts key source attributes.
B	pollingStrategy(Supplier<PollingStrategy> pollingStrategySupplier)	Sets a polling strategy.
protected RetryPolicy	retryPolicy()	Retry policy configured in this builder.
B	retryPolicy(Supplier<RetryPolicy> retryPolicySupplier)	Sets a supplier of RetryPolicy that will be responsible for invocation of AbstractSource.load().
protected T	target()	Returns key source attributes (target).
protected B	thisBuilder()	Returns current builder instance.

Methods inherited from class java.lang.Object

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

Constructor Detail

Builder

protected Builder(Class<T> targetType)

Initializes builder.

Parameters:

targetType - target type

Method Detail

thisBuilder

protected B thisBuilder()

Returns current builder instance.

Returns:

builder instance

init

protected B init(Config metaConfig)

Initialize builder from specified configuration properties.

Supported configuration properties:

• optional - type boolean, see optional()
• polling-strategy - see PollingStrategy for details about configuration format, see pollingStrategy(Supplier) or pollingStrategy(Function)

Parameters:

metaConfig - configuration properties used to initialize a builder instance.

Returns:

modified builder instance

pollingStrategy

public B pollingStrategy(Supplier<PollingStrategy> pollingStrategySupplier)

Sets a polling strategy.

Parameters:

pollingStrategySupplier - a polling strategy

Returns:

a modified builder instance

See Also:

PollingStrategies.regular(java.time.Duration)

pollingStrategy

public final B pollingStrategy(Function<T,Supplier<PollingStrategy>> pollingStrategyProvider)

Sets the polling strategy that accepts key source attributes.

Concrete subclasses should override target() to provide the key source attributes (target). For example, the Builder for a FileConfigSource or ClasspathConfigSource uses the Path to the corresponding file or resource as the key source attribute (target), while the Builder for a UrlConfigSource uses the URL.

Parameters:

pollingStrategyProvider - a polling strategy provider

Returns:

a modified builder instance

Throws:

UnsupportedOperationException - if the concrete Builder implementation does not support the polling strategy

See Also:

pollingStrategy(Supplier), target()

target

protected T target()

Returns key source attributes (target).

Returns:

key source attributes (target).

optional

public B optional()

Built ConfigSource will not be mandatory, i.e. it is ignored if configuration target does not exists.

Returns:

a modified builder instance

changesExecutor

public B changesExecutor(Executor changesExecutor)

Specifies "observe-on" Executor to be used to deliver config source changes. The same executor is also used to reload the source, as triggered by the polling strategy event.

The default executor is from a dedicated thread pool which reuses threads as possible.

Parameters:

changesExecutor - the executor to use for async delivery of Source.changes() events

Returns:

a modified builder instance

See Also:

changesMaxBuffer(int), Source.changes(), PollingStrategy.ticks()

changesMaxBuffer

public B 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: Not consumed events will be dropped off.

Parameters:

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

Returns:

a modified builder instance

See Also:

changesExecutor(Executor), Source.changes()

retryPolicy

public B retryPolicy(Supplier<RetryPolicy> retryPolicySupplier)

Sets a supplier of RetryPolicy that will be responsible for invocation of AbstractSource.load().

The default reply policy is RetryPolicies.justCall().

Create a custom policy or use the built-in policy constructed with a builder.

Parameters:

retryPolicySupplier - a execute policy supplier

Returns:

a modified builder instance

build

public abstract S build()

Builds new instance of S.

Returns:

new instance of S.

isMandatory

protected boolean isMandatory()

Returns mandatory property.

Returns:

mandatory property.

pollingStrategy

protected PollingStrategy pollingStrategy()

Returns polling-strategy property.

Returns:

polling-strategy property.

changesExecutor

protected Executor changesExecutor()

Returns changes-executor property.

Returns:

changes-executor property.

changesMaxBuffer

protected int changesMaxBuffer()

Returns changes-max-buffer property.

Returns:

changes-max-buffer property.

retryPolicy

protected RetryPolicy retryPolicy()

Retry policy configured in this builder.

Returns:

retry policy