public class ConfigTransformer extends Object
ConfigProvider instances and uses them to perform
transformations.
The default variable pattern is of the form ${provider:[path:]key},
where the provider corresponds to a ConfigProvider instance, as passed to
ConfigTransformer(Map). The pattern will extract a set
of paths (which are optional) and keys and then pass them to ConfigProvider.get(String, Set) to obtain the
values with which to replace the variables.
For example, if a Map consisting of an entry with a provider name "file" and provider instance
FileConfigProvider is passed to the ConfigTransformer(Map), and a Properties
file with contents
fileKey=someValuetransform(Map) method, then the transformed
Map will have an entry with key "someKey" and a value "someValue".
This class only depends on ConfigProvider.get(String, Set) and does not depend on subscription support
in a ConfigProvider, such as the ConfigProvider.subscribe(String, Set, ConfigChangeCallback) and
ConfigProvider.unsubscribe(String, Set, ConfigChangeCallback) methods.
| Modifier and Type | Field and Description |
|---|---|
static Pattern |
DEFAULT_PATTERN |
| Constructor and Description |
|---|
ConfigTransformer(Map<String,ConfigProvider> configProviders)
Creates a ConfigTransformer with the default pattern, of the form
${provider:[path:]key}. |
| Modifier and Type | Method and Description |
|---|---|
ConfigTransformerResult |
transform(Map<String,String> configs)
Transforms the given configuration data by using the
ConfigProvider instances to
look up values to replace the variables in the pattern. |
public static final Pattern DEFAULT_PATTERN
public ConfigTransformer(Map<String,ConfigProvider> configProviders)
${provider:[path:]key}.configProviders - a Map of provider names and ConfigProvider instances.public ConfigTransformerResult transform(Map<String,String> configs)
ConfigProvider instances to
look up values to replace the variables in the pattern.configs - the configuration values to be transformedConfigTransformerResult