org.javabits.yar.guice.DefaultBlockingSupplierFactory Maven / Gradle / Ivy

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package org.javabits.yar.guice;

import org.javabits.yar.BlockingSupplier;
import org.javabits.yar.Id;
import org.javabits.yar.Registration;

import static org.javabits.yar.IdMatchers.newKeyMatcher;

/**
 * @author Romain Gilles
 *         Date: 5/31/13
 *         Time: 1:39 PM
 */
public class DefaultBlockingSupplierFactory implements BlockingSupplierFactory {
    @Override
    public  BlockingSupplier create(SimpleRegistry registry, Id id) {
        //maybe a weakmap as guava cache with weak values can help in performance but not sure... to test
        BlockingSupplierImpl supplier = new BlockingSupplierImpl<>(id, registry.getDirectly(id));
        // If an instance of the requested service has been registered, this call will trigger the
        // listener's supplierChanged event with the current value of the service.
        // This is how the supplier instance obtains the initial value of the service.
        Registration registration = registry.addSupplierListener(newKeyMatcher(id), supplier);
        // preserve a reference to the registration to avoid gc and let the caller decides when listener can be gc.
        supplier.setSelfRegistration(registration);
        return supplier;

    }
}