io.scalecube.config.StringConfigProperty Maven / Gradle / Ivy
package io.scalecube.config;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.concurrent.Executor;
import java.util.function.BiConsumer;
import java.util.function.Predicate;
public interface StringConfigProperty extends ConfigProperty {
/**
* Returns value.
*
* @return optional string value
*/
Optional value();
/**
* Shortcut on {@code value().orElse(defaultValue)}.
*
* @return existing value or default
*/
String value(String defaultValue);
/**
* Returns existing value or throws {@link NoSuchElementException} if value is null.
*
* @return existing value or exception
* @throws NoSuchElementException if value is null
*/
String valueOrThrow();
/**
* Adds reload callback to the list. Callbacks will be invoked in the order they were added, and
* only after validation have been passed.
*
* @param callback reload callback, 1st argument is old value 2nd one is new value, both are
* nullable; though callback may throw exception, this wouldn't stop other callbacks from
* execution
*/
void addCallback(BiConsumer callback);
/**
* Adds reload callback to the list. Callbacks will be invoked in the order they were added, and
* only after validation have been passed.
*
* @param executor executor where reload callback will be executed.
* @param callback reload callback, 1st argument is old value 2nd one is new value, both are
* nullable; though callback may throw exception, this wouldn't stop other callbacks from
* execution
*/
void addCallback(Executor executor, BiConsumer callback);
/**
* Adds validator to the list of validators. Validators will be invoked in the order they were
* added. An argument to predicate is nullable.
*
* @throws IllegalArgumentException in case existing value fails against passed {@code validator}
*/
void addValidator(Predicate validator);
}