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Jamal macro library API interfaces
There is a newer version: 2.8.2
package javax0.jamal.api;

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.ServiceLoader;

/**
 * This helper interface can load classes that implement a specific interface using the service loader. If the service
 * loader does not see the classes (the program sees that zero service instances were loaded) then as a fallback it tries
 * to load the {@code META-INF/services/className} files and the classes listed in those.
 * 
 * The Javadoc Taglet execution environment for some reason does not load the service loader loaded instances.
 * This is a workaround.
 * 
 * The {@link Macro} interface extends this interface, because macros are service loaded.
 */
public interface ServiceLoaded {

    /**
     * Load the classes that implement the interface {@code klass} and are provided by the modules or are available.
     * @param klass the interface for which the implementing class instances are needed
     * @param  the interface
     * @return the list of instances
     */
    static  List getInstances(Class klass) {
        ServiceLoader services = ServiceLoader.load(klass);
        List list = new ArrayList<>();
        services.iterator().forEachRemaining(list::add);
        if (list.size() == 0) {
            try {
                for (final var is : loadResources("META-INF/services/" + klass.getName(), ServiceLoaded.class.getClassLoader())) {
                    for (final var className : new String(is.readAllBytes(), StandardCharsets.UTF_8).split("\n")) {
                        try {
                            final var instance = (T) Class.forName(className).getConstructor().newInstance();
                            list.add(instance);
                        } catch (ClassCastException |
                            ClassNotFoundException |
                            NoSuchMethodException |
                            InvocationTargetException |
                            InstantiationException |
                            IllegalAccessException e) {
                            // ignored, here we try our best
                        }
                    }
                }
            } catch (IOException e) {
                //ignored
            }
        }
        return list;
    }


    public static List loadResources(String name, ClassLoader classLoader) throws IOException {
        final List list = new ArrayList<>();
        final Enumeration systemResources =
            (classLoader == null ? ClassLoader.getSystemClassLoader() : classLoader)
                .getResources(name);
        while (systemResources.hasMoreElements()) {
            list.add(systemResources.nextElement().openStream());
        }
        return list;
    }

}