cdc.perfs.api.RuntimeManager Maven / Gradle / Ivy

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package cdc.perfs.api;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import cdc.util.lang.InstallationException;

/**
 * Main API used to create sources, probes and measures.
 *
 * @author Damien Carbonne
 *
 */
public final class RuntimeManager {
    private static final Logger LOGGER = LogManager.getLogger(RuntimeManager.class);
    private static RuntimeService service;

    private RuntimeManager() {
    }

    private static RuntimeService getRuntimeService() {
        if (service == null) {
            try {
                @SuppressWarnings("unchecked")
                final Class cls = (Class) Class.forName("cdc.perfs.runtime.RuntimeEnvironment");
                final Method m = cls.getMethod("getInstance");
                service = (RuntimeService) m.invoke(null);
            } catch (final ClassNotFoundException | NoSuchMethodException | SecurityException | IllegalAccessException | IllegalArgumentException
                    | InvocationTargetException e) {
                LOGGER.catching(e);
                throw new InstallationException("Failed to retrieve RuntimeService implementation", e);
            }
        }
        return service;
    }

    /**
     * Returns the shared source that has a given name.
     * 
     * If a source with that name already exists, then it returns it.
     * Otherwise, creates a new Source and returns it.
     *
     * @param name Name of the source.
     * @return The shared source that is named name.
     */
    public static Source getSource(String name) {
        return getRuntimeService().getSource(name);
    }

    /**
     * Returns the source associated to a class.
     * 

     * Equivalent to getSource(klass.getCanonicalName())
     *
     * @param cls The class whose name will be associated to source.
     * @return getSource(cls.getCanonicalName())
     */
    public static Source getSource(Class cls) {
        return getRuntimeService().getSource(cls);
    }

    /**
     * Creates a probe that can be used to create measures at a given level and
     * associated to a source.
     *
     * @param source The source for which a probe must be created.
     * @param level The level of generated measures.
     * @return An appropriate probe (matching source and level).
     */
    public static RuntimeProbe createProbe(Source source,
                                           MeasureLevel level) {
        return getRuntimeService().createProbe(source, level);
    }

    /**
     * Creates a probe at the MINOR level.
     *
     * @param source The source for which a probe must be created.
     * @return An appropriate probe (matching source and MINOR level).
     */
    public static RuntimeProbe createProbe(Source source) {
        return getRuntimeService().createProbe(source);
    }

    public static interface RuntimeService {
        /**
         * Returns the shared source that has a given name.
         * 

         * If a source with that name already exists, then it returns it.
         * Otherwise, creates a new Source and returns it.
         *
         * @param name Name of the source.
         * @return The shared source that is named name.
         */
        public Source getSource(String name);

        /**
         * Returns the source associated to a class.
         * 
         * Equivalent to getSource(klass.getCanonicalName())
         *
         * @param cls The class whose name will be associated to source.
         * @return getSource(cls.getCanonicalName())
         */
        public default Source getSource(Class cls) {
            return getSource(cls.getCanonicalName());
        }

        /**
         * Creates a probe that can be used to create measures at a given level and
         * associated to a source.
         *
         * @param source The source for which a probe must be created.
         * @param level The level of generated measures.
         * @return An appropriate probe (matching source and level).
         */
        public RuntimeProbe createProbe(Source source,
                                        MeasureLevel level);

        /**
         * Creates a probe at the MINOR level.
         *
         * @param source The source for which a probe must be created.
         * @return An appropriate probe (matching source and MINOR level).
         */
        public RuntimeProbe createProbe(Source source);
    }
}