fish.payara.requesttracing.jaxrs.client.PayaraTracingServices Maven / Gradle / Ivy

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 *  General Public License Version 2 only ("GPL") or the Common Development
 *  and Distribution License("CDDL") (collectively, the "License").  You
 *  may not use this file except in compliance with the License.  You can
 *  obtain a copy of the License at
 *  https://github.com/payara/Payara/blob/master/LICENSE.txt
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 *  file and include the License file at glassfish/legal/LICENSE.txt.
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 *  file that accompanied this code.
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package fish.payara.requesttracing.jaxrs.client;

import org.glassfish.api.invocation.InvocationManager;
import org.glassfish.hk2.api.ServiceHandle;
import org.glassfish.hk2.api.ServiceLocator;
import org.glassfish.internal.api.Globals;
import org.glassfish.internal.deployment.Deployment;

import fish.payara.nucleus.requesttracing.RequestTracingService;
import fish.payara.opentracing.OpenTracingService;
import io.opentracing.Tracer;

/**
 * This is a class hiding internal mechanism of lookup of HK2 services. The
 * required services will be eagerly initialised using their service handles,
 * and throwing an exception if the handle is available but not the service
 * itself.
 *
 * @author David Matejcek
 */
public final class PayaraTracingServices {

    private final RequestTracingService requestTracingService;
    private final OpenTracingService openTracingService;

    private final InvocationManager invocationManager;
    private final Deployment deployment;

    /**
     * Initialise the tracing services if they are available.
     * 
     * @throws RuntimeException if an exception occurs initialising the services.
     */
    public PayaraTracingServices() {
        final ServiceLocator baseServiceLocator = Globals.getStaticBaseServiceLocator();

        requestTracingService = getFromServiceHandle(baseServiceLocator, RequestTracingService.class);
        openTracingService = getFromServiceHandle(baseServiceLocator, OpenTracingService.class);
        invocationManager = getFromServiceHandle(baseServiceLocator, InvocationManager.class);
        deployment = getFromServiceHandle(baseServiceLocator, Deployment.class);
    }

    /**
     * @return true if the Request Tracing services are available and have been
     *         initialised, or false if the services are not available.
     */
    public boolean isTracingAvailable() {
        return requestTracingService != null && openTracingService != null;
    }

    /**
     * @return {@link RequestTracingService}, or null if the HK2 service couldn't be
     *         initialised.
     */
    public RequestTracingService getRequestTracingService() {
        if (isTracingAvailable()) {
            return requestTracingService;
        }
        return null;
    }

    /**
     * @return {@link OpenTracingService}, or null if the HK2 service couldn't be
     *         initialised.
     */
    public OpenTracingService getOpenTracingService() {
        if (isTracingAvailable()) {
            return openTracingService;
        }
        return null;
    }

    /**
     * @return {@link InvocationManager}
     */
    public InvocationManager getInvocationManager() {
        return invocationManager;
    }

    /**
     * @return {@link Deployment}
     */
    public Deployment getDeployment() {
        return deployment;
    }

    /**
     * @return application name known to the actual {@link InvocationManager}, or
     *         null if no invocation manager can be found.
     */
    public String getApplicationName() {
        if (isTracingAvailable()) {
            return openTracingService.getApplicationName(invocationManager);
        }
        return null;
    }

    /**
     * @return actually active {@link Tracer} for the current application, or null
     *         if the tracing service is not available.
     */
    public Tracer getActiveTracer() {
        final String applicationName = getApplicationName();
        if (applicationName == null || !isTracingAvailable()) {
            return null;
        }
        return openTracingService.getTracer(applicationName);
    }

    /**
     * Create a service from the given service locator. Throw an exception if the
     * service handle is available but not the service.
     * 
     * @return the specified service, or null if the service handle isn't available.
     * @throws RuntimeException if the service initialisation failed.
     */
    private static final  T getFromServiceHandle(ServiceLocator serviceLocator, Class serviceClass) {
        ServiceHandle serviceHandle = serviceLocator.getServiceHandle(serviceClass);
        if (serviceHandle != null && serviceHandle.isActive()) {
            return serviceHandle.getService();
        }
        return null;
    }
}