org.eclipse.microprofile.config.inject

Annotation Type ConfigProperty

@Qualifier
 @Retention(value=RUNTIME)
 @Target(value={METHOD,FIELD,PARAMETER,TYPE})
public @interface ConfigProperty

Binds the injection point with a configured value. Can be used to annotate injection points of type TYPE, Optional<TYPE> or javax.inject.Provider<TYPE>, where TYPE can be String and all types which have appropriate converters.

Injected values are the same values that would be retrieved from an injected Config instance or from the instance retrieved from ConfigProvider.getConfig()

Examples

Injecting Native Values

The first sample injects the configured value of the my.long.property property. The injected value does not change even if the underline property value changes in the Config.

Injecting a native value is recommended for a mandatory property and its value does not change at runtime or used by a bean with RequestScoped.

A further recommendation is to use the built in META-INF/microprofile-config.properties file mechanism to provide default values inside an Application. If no configured value exists for this property, a DeplymentException will be thrown during startup.

 @Inject
 @ConfigProperty(name="my.long.property")
 private Long injectedLongValue;
 

Injecting Optional Values

Contrary to natively injecting, if the property is not specified, this will not lead to a DeploymentException. The following code injects a Long value to the my.optional.long.property. If the property does not exist, the value 123 will be assigned. to injectedLongValue.

 @Inject
 @ConfigProperty(name="my.optional.long.property", defaultValue="123")
 private Long injectedLongValue;
 

The following code injects an Optional value of my.optional.int.property.

 @Inject
 @ConfigProperty(name = "my.optional.int.property")
 private Optional<Integer> intConfigValue;
 

Injecting Dynamic Values

The next sample injects a Provider for the value of my.long.property property to resolve the property dynamically. Each invocation to Provider#get() will resolve the latest value from underlying Config again. The existence of configured values will get checked during startup. Instances of Provider<T> are guaranteed to be Serializable.

 @Inject
 @ConfigProperty(name = "my.long.property" defaultValue="123")
 private Provider<Long> longConfigValue;
 

If ConfigProperty is used with a type where no Converter exists, a deployment error will be thrown.

Author:

Ondrej Mihalyi, Emily Jiang, Mark Struberg

Field Summary

Fields

Modifier and Type	Fields and Description
static String	UNCONFIGURED_VALUE

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String	defaultValue The default value if the configured property value does not exist.
String	name The key of the config property used to look up the configuration value.

Field Detail

UNCONFIGURED_VALUE

public static final String UNCONFIGURED_VALUE

Element Detail

name

public abstract String name

The key of the config property used to look up the configuration value. If it is not specified, it will be derived automatically as <class_name>.<injetion_point_name>, where injection_point_name is the field name or parameter name, class_name is the fully qualified name of the class being injected to. If one of the class_name or injection_point_name cannot be determined, the value has to be provided.

Returns:

Name (key) of the config property to inject

Default:

""

defaultValue

public abstract String defaultValue

The default value if the configured property value does not exist.

If the target Type is not String a proper Converter will get applied. That means that any default value string should follow the formatting rules of the registered Converters.

Returns:

the default value as a string

Default:

"org.eclipse.microprofile.config.configproperty.unconfigureddvalue"