https://github.com/ehcache/ehcache3/blob/master/core/src/main/java/org/ehcache/core/spi/service/ServiceFactory.java

package org.ehcache.core.spi.service;

import org.ehcache.spi.service.ServiceProvider;
import org.ehcache.spi.service.Service;
import org.ehcache.spi.service.ServiceCreationConfiguration;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * A factory abstraction that can create {@link Service} instances.
 */
public interface ServiceFactory<T extends Service> {

    /**
     * Returns {@code true} if this factory's services are mandatory in all environments.
     *
     * @return {@code true} if this factory's services are mandatory
     */
    default boolean isMandatory() {
        return false;
    }

    /**
     * Returns an optional ranking integer is used to choose a service factory when multiple factories are available for
     * the same service type. <em>Higher ranking value service factories are preferred.</em>
     *
     * @return a factory ranking value
     */
    default int rank() {
        return 1;
    }

    /**
     * Creates an instance of the service using the passed in {@link ServiceCreationConfiguration}.
     * <p>
     * Note that a {@code null} configuration may be supported or even required by a service implementation.
     *
     * @param configuration the creation configuration, can be {@code null} for some services
     * @return the new service, not {@link Service#start(ServiceProvider) started}
     */
    T create(ServiceCreationConfiguration<T, ?> configuration);

    /**
     * Queries a {@code ServiceFactory} to know which {@link Service} type it produces.
     *
     * @return the class of the produced service.
     */
    Class<? extends T> getServiceType();

    @Retention(RUNTIME)
    @Target(ElementType.TYPE)
    @interface RequiresConfiguration {
    }
}