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package org.glassfish.jersey.server.internal.routing;

import javax.inject.Inject;
import javax.inject.Provider;

import org.glassfish.jersey.server.ContainerRequest;
import org.glassfish.jersey.server.model.MethodHandler;

import org.glassfish.hk2.api.ServiceLocator;

/**
 * Terminal router that pushes the matched method's handler instance to the stack
 * returned by {@link javax.ws.rs.core.UriInfo#getMatchedResources()} method.
 *
 * @author Marek Potociar (marek.potociar at oracle.com)
 */
class PushMethodHandlerRouter implements Router {

    /**
     * An injectable factory of {@link PushMethodHandlerRouter} instances.
     */
    static class Builder {

        @Inject
        private Provider<RoutingContext> routingContextFactory;
        @Inject
        private ServiceLocator injector;
        @Inject
        private ServiceLocator locator;

        /**
         * Build a new {@link PushMethodHandlerRouter} instance.
         *
         * @param methodHandler method handler model providing the method handler
         *                      instance.
         * @param next          next router to be invoked after the this one.
         * @return new {@code PushMethodHandlerRouter} instance.
         */
        public PushMethodHandlerRouter build(final MethodHandler methodHandler, Router next) {
            return new PushMethodHandlerRouter(routingContextFactory, locator, methodHandler, next);
        }

    }

    private final ServiceLocator locator;
    private final Provider<RoutingContext> routingContextFactory;
    private final MethodHandler methodHandler;
    private final Router next;

    private PushMethodHandlerRouter(
            final Provider<RoutingContext> routingContextFactory,
            final ServiceLocator locator,
            final MethodHandler methodHandler,
            final Router next) {
        this.locator = locator;
        this.routingContextFactory = routingContextFactory;
        this.methodHandler = methodHandler;
        this.next = next;
    }

    @Override
    public Continuation apply(final ContainerRequest request) {

        final Object storedResource = routingContextFactory.get().peekMatchedResource();
        if (storedResource == null || !storedResource.getClass().equals(methodHandler.getHandlerClass())) {
            Object handlerInstance = methodHandler.getInstance(locator);
            routingContextFactory.get().pushMatchedResource(handlerInstance);
        }
        return Continuation.of(request, next);
    }
}
