The application can register onChange listeners to handle changes to configuration properties at runtime. Plugins or code can dynamically load and change properties and this can fire any registered callback handlers.
Examples
int port = Config.getInt("app.port", 8090);
String topicName = Config.get("app.topic.name");
List<Integer> codes = Config.list().ofInt("my.codes", 42, 54);
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Method Summary
Modifier and TypeMethodDescriptionstatic Configuration
Return the underlying configuration.static Properties
Return the loaded properties as standard Properties map.static void
clearProperty
(String key) Clear the value for the given key.static boolean
Return boolean configuration value with the given default value.static boolean
Return boolean configuration value with the given default value.static ModificationEvent.Builder
eventBuilder
(String name) Create an event builder to make changes to the configuration.static Configuration
Return the configuration for a path.static String
Return a required configuration value as String.static String
Return a configuration string value with a given default.static <T> T
Apply a mapping function to the value returned.static <T> Optional
<T> getAsOptional
(String key, Function<String, T> mappingFunction) Apply a mapping function to the value returned as an optional.static boolean
Return a required boolean configuration value.static boolean
Return a configuration value as boolean given a default value.static BigDecimal
getDecimal
(String key) Return a decimal configuration value.static BigDecimal
getDecimal
(String key, String defaultValue) Return a decimal configuration value with a default value.static Duration
getDuration
(String key) Return a Duration configuration value.static Duration
getDuration
(String key, String defaultValue) Return a Duration configuration value with a default value.static <T extends Enum<T>>
TReturn the enum configuration value.static <T extends Enum<T>>
TReturn the enum configuration value with a default value.static int
Return a required int configuration value.static int
Return a configuration value as int given a default value.static long
Return a required long configuration value.static long
Return a configuration value as long given a default value.static String
getNullable
(String key) Return a configuration value as String or null if it is not defined.static String
getNullable
(String key, String defaultValue) Return a configuration value as String or null if it is not defined.getOptional
(String key) Return a configuration value that might not exist.getOptional
(String key, String defaultValue) Return a configuration value that might not exist.static URI
Return a URI configuration value.static URI
Return a URI configuration value with a default value.static Configuration.ListValue
list()
Return a List of values configured.static void
Put all loaded properties into System properties.static void
Register a callback for a change to the given configuration key.static void
onChange
(Consumer<ModificationEvent> bulkChangeEventListener, String... keys) Register an event listener that will be notified of configuration changes.static void
onChangeBool
(String key, Consumer<Boolean> singlePropertyChangeListener) Register a callback for a change to the given configuration key as a Boolean value.static void
onChangeInt
(String key, IntConsumer singlePropertyChangeListener) Register a callback for a change to the given configuration key as an Int value.static void
onChangeLong
(String key, LongConsumer singlePropertyChangeListener) Register a callback for a change to the given configuration key as a Long value.static void
Add configuration values via a map.static Configuration.SetValue
set()
Return a Set of values configured.static void
setProperty
(String key, String value) Set a single configuration value.
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Method Details
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asProperties
Return the loaded properties as standard Properties map. -
forPath
Return the configuration for a path.Examples
Say you have a set of properties like this
example.path.prefix1=1
example.path.prefix2=2
Configuration config = Config.forPath("example.path"); Configuration config2 = Config.forPath("example").forPath("path"); // will output "1" int number = config.getInt("prefix1"); // will output "2" number = config2.getInt("prefix2");
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asConfiguration
Return the underlying configuration. -
loadIntoSystemProperties
public static void loadIntoSystemProperties()Put all loaded properties into System properties. -
get
Return a required configuration value as String.IllegalStateException is thrown if the value is not defined in configuration.
- Parameters:
key
- The configuration key- Returns:
- The configured value
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get
Return a configuration string value with a given default.- Parameters:
key
- The configuration keydefaultValue
- The default value used- Returns:
- The configured or default value
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getOptional
Return a configuration value that might not exist.- Parameters:
key
- The configuration key- Returns:
- The configured value wrapped as optional
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getOptional
Return a configuration value that might not exist.- Parameters:
key
- The configuration keydefaultValue
- The default value that can be null- Returns:
- The configured value wrapped as optional
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getNullable
Return a configuration value as String or null if it is not defined.This is an alternative to
getOptional(String)
for cases where we prefer to work with null values rather than Optional.- Parameters:
key
- The configuration key- Returns:
- The configured value or null if not set
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getNullable
Return a configuration value as String or null if it is not defined.This is an alternative to
getOptional(String)
for cases where we prefer to work with null values rather than Optional.- Parameters:
key
- The configuration keydefaultValue
- The default value that can be null- Returns:
- The configured value or null if not set
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enabled
Return boolean configuration value with the given default value.This is the same as
getBool(String)
.IllegalStateException is thrown if the value is not defined in configuration.
if (Config.enabled("feature.cleanup")) { ... }
- Parameters:
key
- The configuration key- Returns:
- True when configuration value is true
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enabled
Return boolean configuration value with the given default value.This is the same as
getBool(String, boolean)
.if (Config.enabled("feature.cleanup", true)) { ... }
- Parameters:
key
- The configuration key- Returns:
- True when configuration value is true
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getBool
Return a required boolean configuration value.IllegalStateException is thrown if the value is not defined in configuration.
- Parameters:
key
- The configuration key- Returns:
- The configured value
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getBool
Return a configuration value as boolean given a default value.- Parameters:
key
- The configuration keydefaultValue
- The default value used- Returns:
- The configured or default value
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getInt
Return a required int configuration value.IllegalStateException is thrown if the value is not defined in configuration.
- Parameters:
key
- The configuration key- Returns:
- The configured value
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getInt
Return a configuration value as int given a default value.- Parameters:
key
- The configuration keydefaultValue
- The default value used- Returns:
- The configured or default value
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getLong
Return a required long configuration value.IllegalStateException is thrown if the value is not defined in configuration.
- Parameters:
key
- The configuration key- Returns:
- The configured value
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getLong
Return a configuration value as long given a default value.- Parameters:
key
- The configuration keydefaultValue
- The default value used- Returns:
- The configured or default value
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getDecimal
Return a decimal configuration value.- Parameters:
key
- The configuration key- Returns:
- The configured value
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getDecimal
Return a decimal configuration value with a default value.IllegalStateException is thrown if the value is not defined in configuration.
- Parameters:
key
- The configuration keydefaultValue
- The default value- Returns:
- The configured value
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getURI
Return a URI configuration value.IllegalStateException is thrown if the value is not defined in configuration.
- Parameters:
key
- The configuration key- Returns:
- The configured value
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getURI
Return a URI configuration value with a default value.- Parameters:
key
- The configuration keydefaultValue
- The default value- Returns:
- The configured value
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getDuration
Return a Duration configuration value.IllegalStateException is thrown if the value is not defined in configuration.
- Parameters:
key
- The configuration key- Returns:
- The configured value
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getDuration
Return a Duration configuration value with a default value.- Parameters:
key
- The configuration keydefaultValue
- The default value- Returns:
- The configured value
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getEnum
Return the enum configuration value.IllegalStateException is thrown if the value is not defined in configuration.
- Parameters:
type
- The enum typekey
- The configuration key- Returns:
- The configured value
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getEnum
Return the enum configuration value with a default value.- Parameters:
type
- The enum typekey
- The configuration keydefaultValue
- The default value- Returns:
- The configured value
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getAs
Apply a mapping function to the value returned.- Parameters:
key
- The configuration keymappingFunction
- the mapping function to execute- Returns:
- The mapped value
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getAsOptional
Apply a mapping function to the value returned as an optional.- Parameters:
key
- The configuration keymappingFunction
- the mapping function to execute- Returns:
- The mapped value
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list
Return a List of values configured.List<Integer> codes = Config.list().ofInt("my.codes", 97, 45);
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set
Return a Set of values configured.Set<String> operations = Config.set().of("my.operations", "put","delete");
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eventBuilder
Create an event builder to make changes to the configuration.configuration.eventBuilder("MyChanges") .put("someKey", "val0") .put("someOther.key", "42") .remove("foo") .publish();
- Parameters:
name
- The name of the event which defines the source of the configuration value.- See Also:
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setProperty
Set a single configuration value. Note thateventBuilder(String)
should be used to fluently set multiple configuration values.This will fire configuration callback listeners that are registered.
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putAll
Add configuration values via a map.This will fire configuration callback listeners that are registered.
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clearProperty
Clear the value for the given key. Note thateventBuilder(String)
should be used when setting multiple configuration values.This will fire configuration callback listeners that are registered.
- Parameters:
key
- The configuration key we want to clear
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onChange
Register an event listener that will be notified of configuration changes.If we are only interested in changes to a single property it is easier to use
onChange(String, Consumer)
or the variants for int, long, boolean onChangeInt(), onChangeLong(), onChangeBool().Typically, we use this when we are interested in changes to multiple properties and want to get and act on the values of multiple properties.
configuration.onChange((modificationEvent) -> { String newValue = modificationEvent.configuration().get("myFirstKey"); int newInt = modificationEvent.configuration().getInt("myOtherKey"); // do something ... });
When we are only interested if some specific properties have changed then we can define those. The event listener will be invoked if there is a change to any of those keys.
configuration.onChange((event) -> { String newValue = event.configuration().get("myFirstInterestingKey"); int newInt = event.configuration().getInt("myOtherInterestingKey"); // do something ... }, "myFirstInterestingKey", "myOtherInterestingKey");
- Parameters:
bulkChangeEventListener
- The listener that is called when changes have occurredkeys
- Optionally specify keys when the listener is only interested if changes are made for these specific properties
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onChange
Register a callback for a change to the given configuration key.Use this when we are only interested in changes to a single configuration property. If we are interested in multiple properties we should use
onChange(Consumer, String...)
configuration.onChange("myKey", (newValue) -> { // do something with the newValue ... )};
- Parameters:
key
- The configuration key we want to detect changes tosinglePropertyChangeListener
- The callback handling to fire when the configuration changes.
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onChangeInt
Register a callback for a change to the given configuration key as an Int value.Use this when we are only interested in changes to a single configuration property. If we are interested in multiple properties we should use
onChange(Consumer, String...)
- Parameters:
key
- The configuration key we want to detect changes tosinglePropertyChangeListener
- The callback handling to fire when the configuration changes.
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onChangeLong
Register a callback for a change to the given configuration key as a Long value.Use this when we are only interested in changes to a single configuration property. If we are interested in multiple properties we should use
onChange(Consumer, String...)
- Parameters:
key
- The configuration key we want to detect changes tosinglePropertyChangeListener
- The callback handling to fire when the configuration changes.
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onChangeBool
Register a callback for a change to the given configuration key as a Boolean value.Use this when we are only interested in changes to a single configuration property. If we are interested in multiple properties we should use
onChange(Consumer, String...)
- Parameters:
key
- The configuration key we want to detect changes tosinglePropertyChangeListener
- The callback handling to fire when the configuration changes.
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