Enclosing interface:

Config
```
public static interface Config.Builder
```
Config Builder.
A factory for a Config object.
The application can set the following characteristics:
- overrides - instance of override source;
- sources - instances of configuration source;
- mappers - ordered list of mapper functions. It is also possible to disable loading of ConfigMapperProviders as a service.
- parsers - ordered list of configuration content parsers. It is also possible to disable loading of ConfigParsers as a service.
- token reference resolving - a resolving of reference tokens in a key can be disabled
- filters - ordered list of configuration value filters. It is also possible to disable loading of ConfigFilters as a service.
- caching - can be elementary configuration value processed by filter cached?
In case of ConfigMapperProviders, if there is no one that could be used to map appropriate type, the mapping attempt throws a ConfigMappingException.
A more sophisticated approach can be achieved using the "config beans" module, that provides reflection access and mapping for static factory methods, constructors, builder patterns and more.
If a ConfigSource is not specified, following default config source is used. Same as Config.create() uses. It builds composite config source from following sources, checked in order:
1. Tries to load configuration from meta one of following meta configuration files on classpath, in order:
  1. meta-config.yaml - meta configuration file in YAML format
  2. meta-config.conf - meta configuration file in HOCON format
  3. meta-config.json - meta configuration file in JSON format
  4. meta-config.properties - meta configuration file in Java Properties format
2. Otherwise, configuration consists of:
  1. Environment variables;
  2. or else System properties
  3. one of following files on classpath, checked in order:
    1. application.yaml - configuration file in YAML format
    2. application.conf - configuration file in HOCON format
    3. application.json - configuration file in JSON format
    4. application.properties - configuration file in Java Properties format
It uses the first and only one file that exists and there is a ConfigParser available that supports appropriate media type. Available parser means that the parser:
1. is loaded as a service using ServiceLoader;
2. or if it does not exist, a config core built-in parser is used, if exists.
See Also:

Config.create(), ConfigSource, ConfigParser, ConfigFilter

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`Config.Builder`	`addFilter(ConfigFilter configFilter)`	Registers a `ConfigFilter` instance that will be used by `Config` to filter elementary value before it is returned to a user.
`Config.Builder`	`addFilter(Function<Config,ConfigFilter> configFilterProvider)`	Registers a `ConfigFilter` provider as a `Function`<`Config`, `ConfigFilter`>.
`Config.Builder`	`addFilter(Supplier<Function<Config,ConfigFilter>> configFilterSupplier)`	Registers a `ConfigFilter` provider as a `Supplier`<`Function`<`Config`, `ConfigFilter`>>.
`<T> Config.Builder`	`addMapper(GenericType<T> type, Function<Config,T> mapper)`	Register a mapping function for specified `GenericType`.
`Config.Builder`	`addMapper(ConfigMapperProvider configMapperProvider)`	Registers a `ConfigMapperProvider` with a map of `String` to specified `type`.
`<T> Config.Builder`	`addMapper(Class<T> type, Function<Config,T> mapper)`	Registers mapping function for specified `type`.
`Config.Builder`	`addParser(ConfigParser configParser)`	Registers a `ConfigParser` instance that can be used by registered `ConfigSource`s to parse `configuration content`.
`<T> Config.Builder`	`addStringMapper(Class<T> type, Function<String,T> mapper)`	Registers simple `Function` from `String` for specified `type`.
`Config`	`build()`	Builds new instance of `Config`.
`Config.Builder`	`changesExecutor(Executor changesExecutor)`	Specifies "observe-on" `Executor` to be used by `Config.changes()` to deliver new Config instance.
`Config.Builder`	`changesMaxBuffer(int changesMaxBuffer)`	Specifies maximum capacity for each subscriber's buffer to be used by by `Config.changes()` to deliver new Config instance.
`Config.Builder`	`disableCaching()`	Disables caching of elementary configuration values on `Config` side.
`Config.Builder`	`disableEnvironmentVariablesSource()`	Disables use of `environment variables config source`.
`Config.Builder`	`disableFilterServices()`	Disables automatic registration of filters loaded as a `service`.
`Config.Builder`	`disableKeyResolving()`	Disables an usage of resolving key tokens.
`Config.Builder`	`disableMapperServices()`	Disables automatic registration of mappers via `ConfigMapperProvider` SPI loaded as a `service`.
`Config.Builder`	`disableParserServices()`	Disables automatic registration of parsers loaded as a `service`.
`Config.Builder`	`disableSystemPropertiesSource()`	Disables use of `system properties config source`.
`Config.Builder`	`disableValueResolving()`	Disables an usage of resolving value tokens.
`Config.Builder`	`mappersFrom(Config config)`	Add mappers from another config instance.
`Config.Builder`	`overrides(Supplier<OverrideSource> overridingSource)`	Sets source of a override source.
`default Config.Builder`	`sources(Supplier<ConfigSource> configSource)`	Sets a `ConfigSource` instance to be used as a source of configuration to be wrapped into `Config` API.
`default Config.Builder`	`sources(Supplier<ConfigSource> configSource, Supplier<ConfigSource> configSource2)`	Sets an ordered pair of `ConfigSource` instances to be used as single source of configuration to be wrapped into `Config` API.
`default Config.Builder`	`sources(Supplier<ConfigSource> configSource, Supplier<ConfigSource> configSource2, Supplier<ConfigSource> configSource3)`	Sets an ordered trio of `ConfigSource` instances to be used as single source of configuration to be wrapped into `Config` API.
`Config.Builder`	`sources(List<Supplier<ConfigSource>> configSources)`	Sets ordered list of `ConfigSource` instance to be used as single source of configuration to be wrapped into `Config` API.

- Method Detail
  - sources
```
Config.Builder sources(List<Supplier<ConfigSource>> configSources)
```
    Sets ordered list of ConfigSource instance to be used as single source of configuration to be wrapped into Config API.
    Configuration sources found earlier in the list are considered to have a higher priority than the latter ones. I.e., when resolving a value of a key, the sources are consulted in the order they have been provided and as soon as the value is found in a configuration source, the value immediately is returned without consulting any of the remaining configuration sources in the prioritized collection.
    This is default implementation of ConfigSources.create(Supplier...) Composite ConfigSource} provided by Fallback MergingStrategy. It is possible to use custom implementation of merging strategy.
    builder.source(ConfigSources.create(source1, source2, source3) .mergingStrategy(new MyMergingStrategy));
    Target source is composed from following sources, in order:
    
    environment variables config source
    Can disabled by disableEnvironmentVariablesSource()
    
    system properties config source Can disabled by disableSystemPropertiesSource()
    
    Source(s) specified by user in the method.
    Parameters:
    
    configSources - ordered list of configuration sources
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    disableEnvironmentVariablesSource(), disableSystemPropertiesSource(), ConfigSources.create(Supplier...), ConfigSources.CompositeBuilder, ConfigSources.MergingStrategy
  - sources
```
default Config.Builder sources(Supplier<ConfigSource> configSource)
```
    Sets a ConfigSource instance to be used as a source of configuration to be wrapped into Config API.
    Target source is composed from configSource and following sources (unless they are disabled) in order:
    
    environment variables config source
    Can disabled by disableEnvironmentVariablesSource()
    
    system properties config source Can disabled by disableSystemPropertiesSource()
    
    Source(s) specified by user in the method.
    Parameters:
    
    configSource - the only config source
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    Config.create(Supplier...), sources(List), disableEnvironmentVariablesSource(), disableSystemPropertiesSource()
  - sources
```
default Config.Builder sources(Supplier<ConfigSource> configSource,
                               Supplier<ConfigSource> configSource2)
```
    Sets an ordered pair of ConfigSource instances to be used as single source of configuration to be wrapped into Config API.
    Target source is composed from configSource and following sources (unless they are disabled) in order:
    
    environment variables config source
    Can disabled by disableEnvironmentVariablesSource()
    
    system properties config source Can disabled by disableSystemPropertiesSource()
    
    Source(s) specified by user in the method.
    Parameters:
    
    configSource - the first config source
    
    configSource2 - the second config source
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    Config.create(Supplier...), sources(List), disableEnvironmentVariablesSource(), disableSystemPropertiesSource()
  - sources
```
default Config.Builder sources(Supplier<ConfigSource> configSource,
                               Supplier<ConfigSource> configSource2,
                               Supplier<ConfigSource> configSource3)
```
    Sets an ordered trio of ConfigSource instances to be used as single source of configuration to be wrapped into Config API.
    Target source is composed from config sources parameters and following sources (unless they are disabled) in order:
    
    environment variables config source
    Can disabled by disableEnvironmentVariablesSource()
    
    system properties config source Can disabled by disableSystemPropertiesSource()
    
    Source(s) specified by user in the method.
    Parameters:
    
    configSource - the first config source
    
    configSource2 - the second config source
    
    configSource3 - the third config source
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    Config.create(Supplier...), sources(List), disableEnvironmentVariablesSource(), disableSystemPropertiesSource()
  - overrides
```
Config.Builder overrides(Supplier<OverrideSource> overridingSource)
```
    Sets source of a override source.
    The feature allows user to override existing values with other ones, specified by wildcards. Default values might be defined with key token references (i.e. $env.$pod.logging.level: INFO) that might be overridden by a config source with a higher priority to identify the current environment (i.e. env: test and pod: qwerty. The overrides are able to redefine values using wildcards (or without them). For example test.*.logging.level = FINE overrides logging.level for all pods in test environment.
    Override definitions are applied before any filter.
    
    Parameters:
    
    overridingSource - a source with overriding key patterns and assigned values
    
    Returns:
    
    an updated builder instance
  - disableKeyResolving
```
Config.Builder disableKeyResolving()
```
    Disables an usage of resolving key tokens.
    A key can contain tokens starting with $ (i.e. $host.$port), that are resolved by default and tokens are replaced with a value of the key with the token as a key.
    
    Returns:
    
    an updated builder instance
  - disableValueResolving
```
Config.Builder disableValueResolving()
```
    Disables an usage of resolving value tokens.
    A value can contain tokens enclosed in ${} (i.e. ${name}), that are resolved by default and tokens are replaced with a value of the key with the token as a key.
    
    Returns:
    
    an updated builder instance
  - disableEnvironmentVariablesSource
```
Config.Builder disableEnvironmentVariablesSource()
```
    Disables use of environment variables config source.
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    ConfigSources.environmentVariables()
  - disableSystemPropertiesSource
```
Config.Builder disableSystemPropertiesSource()
```
    Disables use of system properties config source.
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    ConfigSources.systemProperties()
  - addMapper
```
<T> Config.Builder addMapper(Class<T> type,
                             Function<Config,T> mapper)
```
    Registers mapping function for specified type. The last registration of same type overwrites previous one. Programmatically registered mappers have priority over other options.
    As another option, mappers are loaded automatically as a service via ConfigMapperProvider SPI unless it is disabled.
    And the last option, built-in mappers are registered.
    
    Type Parameters:
    
    T - type the mapper is registered for
    
    Parameters:
    
    type - class of type the mapper is registered for
    
    mapper - mapping function
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    addStringMapper(Class, Function), addMapper(ConfigMapperProvider), disableMapperServices()
  - addMapper
```
<T> Config.Builder addMapper(GenericType<T> type,
                             Function<Config,T> mapper)
```
    Register a mapping function for specified GenericType. This is useful for mappers that support specificly typed generics, such as Map<String, Integer> or Set<Foo<Bar>>. To support mappers that can map any type (e.g. all cases of Map<String, V>), use addMapper(ConfigMapperProvider) as it gives you full control over which types are supported, through ConfigMapperProvider.mapper(GenericType).
    
    Type Parameters:
    
    T - type of the result
    
    Parameters:
    
    type - generic type to register a mapper for
    
    mapper - mapping function
    
    Returns:
    
    updated builder instance
  - addStringMapper
```
<T> Config.Builder addStringMapper(Class<T> type,
                                   Function<String,T> mapper)
```
    Registers simple Function from String for specified type. The last registration of same type overwrites previous one. Programmatically registered mappers have priority over other options.
    As another option, mappers are loaded automatically as a service via ConfigMapperProvider SPI, if not disabled.
    And the last option, built-in mappers are registered.
    
    Type Parameters:
    
    T - type the mapper is registered for
    
    Parameters:
    
    type - class of type the mapper is registered for
    
    mapper - mapper instance
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    addMapper(ConfigMapperProvider), ConfigMappers, disableMapperServices()
  - addMapper
```
Config.Builder addMapper(ConfigMapperProvider configMapperProvider)
```
    Registers a ConfigMapperProvider with a map of String to specified type. The last registration of same type overwrites previous one. Programmatically registered mappers have priority over other options.
    As another option, mappers are loaded automatically as a service via ConfigMapperProvider SPI, if not disabled.
    And the last option, built-in mappers are registered.
    
    Parameters:
    
    configMapperProvider - mapper provider instance
    
    Returns:
    
    modified builder instance
    
    See Also:
    
    addStringMapper(Class, Function), ConfigMappers, disableMapperServices()
  - disableMapperServices
```
Config.Builder disableMapperServices()
```
    Disables automatic registration of mappers via ConfigMapperProvider SPI loaded as a service.
    Order of configuration mapper providers loaded as a service is defined by Priority annotation.
    Automatic registration of mappers as a service is enabled by default.
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    ConfigMapperProvider
  - addParser
```
Config.Builder addParser(ConfigParser configParser)
```
    Registers a ConfigParser instance that can be used by registered ConfigSources to parse configuration content. Parsers are tried to be used by ConfigContext.findParser(String) in same order as was registered by the addParser(ConfigParser) method. Programmatically registered parsers have priority over other options.
    As another option, parsers are loaded automatically as a service, if not disabled.
    
    Parameters:
    
    configParser - parser instance
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    disableParserServices()
  - disableParserServices
```
Config.Builder disableParserServices()
```
    Disables automatic registration of parsers loaded as a service.
    Order of configuration parsers loaded as a service is defined by Priority annotation.
    Automatic registration of parsers as a service is enabled by default.
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    ConfigParser
  - addFilter
```
Config.Builder addFilter(ConfigFilter configFilter)
```
    Registers a ConfigFilter instance that will be used by Config to filter elementary value before it is returned to a user.
    Filters are applied in same order as was registered by the addFilter(ConfigFilter), addFilter(Function) or addFilter(Supplier) method.
    ConfigFilter is actually a BiFunction<String,String,String> where the first input parameter is the config key, the second is the original value and the result is the new value. So the filter can be added as simply as:
    Config.builder() .addFilter((key, originalValue) -> originalValue.toUpperCase()) .build();
    The config system will automatically load filters defined as a service, unless disabled.
    Parameters:
    
    configFilter - filter instance
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    addFilter(Function), addFilter(Supplier)
  - addFilter
```
Config.Builder addFilter(Function<Config,ConfigFilter> configFilterProvider)
```
    Registers a ConfigFilter provider as a Function<Config, ConfigFilter>. An obtained filter will be used by Config to filter elementary value before it is returned to a user.
    Filters are applied in same order as was registered by the addFilter(ConfigFilter), addFilter(Function) or addFilter(Supplier) method.
    Registered provider's Function.apply(Object) method is called every time the new Config is created. Eg. when this builder's build() method creates the Config or when the new change event is fired with new Config instance with its own filter instance is created.
    
    Parameters:
    
    configFilterProvider - a config filter provider as a function of Config to ConfigFilter
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    addFilter(ConfigFilter), addFilter(Supplier)
  - addFilter
```
Config.Builder addFilter(Supplier<Function<Config,ConfigFilter>> configFilterSupplier)
```
    Registers a ConfigFilter provider as a Supplier<Function<Config, ConfigFilter>>. An obtained filter will be used by Config to filter elementary value before it is returned to a user.
    Filters are applied in same order as was registered by the addFilter(ConfigFilter), addFilter(Function) or addFilter(Supplier) method.
    Registered provider's Function.apply(Object) method is called every time the new Config is created. Eg. when this builder's build() method creates the Config or when the new change event is fired with new Config instance with its own filter instance is created.
    
    Parameters:
    
    configFilterSupplier - a config filter provider as a supplier of a function of Config to ConfigFilter
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    addFilter(ConfigFilter), addFilter(Function)
  - disableFilterServices
```
Config.Builder disableFilterServices()
```
    Disables automatic registration of filters loaded as a service.
    Order of configuration filters loaded as a service is defined by Priority annotation.
    Automatic registration of filters as a service is enabled by default.
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    ConfigFilter
  - disableCaching
```
Config.Builder disableCaching()
```
    Disables caching of elementary configuration values on Config side.
    Caching is about ConfigFilters. With disabled caching, registered filters are applied always you access elementary configuration value. With enabled caching, registered filters are applied just once per unique config node (key). Repeated access of already filtered key directly returns already cached value.
    Caching is enabled by default.
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    addFilter(ConfigFilter)
  - changesExecutor
```
Config.Builder changesExecutor(Executor changesExecutor)
```
    Specifies "observe-on" Executor to be used by Config.changes() to deliver new Config instance. Executor is also used to process reloading of config from appropriate source.
    By default dedicated thread pool that creates new threads as needed, but will reuse previously constructed threads when they are available is used.
    
    Parameters:
    
    changesExecutor - the executor to use for async delivery of Config.changes() events
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    changesMaxBuffer(int), Config.changes(), Config.onChange(Function), Source.changes()
  - changesMaxBuffer
```
Config.Builder changesMaxBuffer(int changesMaxBuffer)
```
    Specifies maximum capacity for each subscriber's buffer to be used by by Config.changes() to deliver new Config instance.
    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 Config.changes() events.
    
    Returns:
    
    an updated builder instance
    
    See Also:
    
    changesExecutor(Executor), Config.changes(), Config.onChange(Function)
  - build
```
Config build()
```
    Builds new instance of Config.
    
    Returns:
    
    new instance of Config.
  - mappersFrom
```
Config.Builder mappersFrom(Config config)
```
    Add mappers from another config instance. This may be useful if we need the same conversion behavior.
    
    Parameters:
    
    config - config to extract mappers from
    
    Returns:
    
    updated builder instance

Interface Config.Builder

Method Summary

Method Detail

sources

sources

sources

sources

overrides

disableKeyResolving

disableValueResolving

disableEnvironmentVariablesSource

disableSystemPropertiesSource

addMapper

addMapper

addStringMapper

addMapper

disableMapperServices

addParser

disableParserServices

addFilter

addFilter

addFilter

disableFilterServices

disableCaching

changesExecutor

changesMaxBuffer

build

mappersFrom