Module org.microbean.loader.microprofile.config.configsource

Package org.microbean.loader.microprofile.config.configsource

Class ConfigSourceProvider

java.lang.Object

org.microbean.loader.microprofile.config.configsource.ConfigSourceProvider

All Implemented Interfaces:

Provider

public class ConfigSourceProvider
extends Object
implements Provider

A Provider that uses a MicroProfile Config ConfigSource and MicroProfile Config Converters to produce Values.

Author:

Laird Nelson

See Also:

• get(Loader, Path)
• ConfigSource.getValue(String)
• Converter.convert(String)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	ConfigSourceProvider.ConverterRegistration<T>	A coupling of a Type, a priority (as defined in the MicroProfile Config specification), and a Converter.

Constructor Summary

Constructors

Constructor	Description
ConfigSourceProvider(ConfigSource configSource, Collection<? extends ConfigSourceProvider.ConverterRegistration<?>> converterRegistrations)	Creates a new ConfigSourceProvider.
ConfigSourceProvider(ConfigSource configSource, Map<? extends Type,? extends Converter<?>> converters)	Creates a new ConfigSourceProvider.

Method Summary

Modifier and Type	Method	Description
final Value<?>	get(Loader<?> requestor, Path<? extends Type> absolutePath)	Returns a Value suitable for the supplied Loader and Path, or null if there is no such Value now and if there never will be such a Value for the supplied arguments.
final Type	lowerBound()	Returns a Type representing the lower type bound of all possible values supplied by this Provider.

Methods inherited from class java.lang.Object

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

Constructor Details

ConfigSourceProvider

public ConfigSourceProvider(ConfigSource configSource,
 Map<? extends Type,? extends Converter<?>> converters)

Creates a new ConfigSourceProvider.

Parameters:

configSource - the ConfigSource whose getValue(String) method will be used to back Values produced by the get(Loader, Path) method; must not be null

converters - a Map of Converters indexed by their conversion Type; may be null

Throws:

NullPointerException - if configSource is null

ConfigSourceProvider

public ConfigSourceProvider(ConfigSource configSource,
 Collection<? extends ConfigSourceProvider.ConverterRegistration<?>> converterRegistrations)

Creates a new ConfigSourceProvider.

Parameters:

configSource - the ConfigSource whose getValue(String) method will be used to back Values produced by the get(Loader, Path) method; must not be null

converterRegistrations - a Collection of ConfigSourceProvider.ConverterRegistrations; may be null

Throws:

NullPointerException - if configSource is null

See Also:

• ConfigSourceProvider.ConverterRegistration

Method Details

lowerBound

public final Type lowerBound()

Description copied from interface: Provider

Returns a Type representing the lower type bound of all possible values supplied by this Provider.

Often the value returned by implementations of this method is no more specific than the lowest possible type, which is null, meaning that the Provider has a chance of producing a Value for any requested type.

A return value of, for example, String.class indicates that the Provider may satisfy requests for String.class, or any of its supertypes (such as CharSequence or Object), but cannot satisfy requests for Integer.class, for example.

A return value of Object.class would be extremely unusual and would indicate a maximally opaque type, i.e. only requests for exactly Object.class have the possibility of being satisfied by this Provider. Such a return value is possible, but rarely used, and Provider implementations are urged to consider returning a different Type.

Note that this method is used solely to help eliminate types from consideration, not permit them. That is, although Provider may indicate via an implementation of this method that a given Type is suitable, it is not thereby obliged to return a Value corresponding to it from its get(Loader, Path) method implementation.

The default implementation of this method returns null. Many Provider implementations will choose not to override this method.

Specified by:

lowerBound in interface Provider

Returns:

a Type representing the lower type bound of all possible values supplied by this Provider, or null to indicate the lowest possible type bound

get

public final Value<?> get(Loader<?> requestor,
 Path<? extends Type> absolutePath)

Description copied from interface: Provider

Returns a Value suitable for the supplied Loader and Path, or null if there is no such Value now and if there never will be such a Value for the supplied arguments.

In addition to the other requirements described here, the following assertions will be (and must be) true when this method is called in the normal course of events:

• assert absolutePath.isAbsolute();
• assert absolutePath.startsWith(requestor.absolutePath());
• assert !absolutePath.equals(requestor.absolutePath());

If any caller does not honor these requirements, undefined behavior may result.

Specified by:

get in interface Provider

Parameters:

requestor - the Loader seeking a Value; must not be null

absolutePath - an absolute Path for which the supplied Loader is seeking a value; must not be null

Returns:

a Value more or less suitable for the combination of the supplied Loader and Path, or null if there is no such Value now and if there never will be such a Value for the supplied arguments