* <li>Instance variables are not allowed.</li>
 * <li>Non-final static variables are not allowed (i.e. constants are allowed).</li>
 * <li>Methods cannot be overloaded.</li>
 * <li>Implementations cannot be generic (i.e. cannot use type parameters).</li>
 * </ul>
 */
@Incubating
public class RuleSource {

        private static String foo;
    }

    public static class InnerPublicStaticClass extends RuleSource {
    }

    public static class HasExplicitDefaultConstructor extends RuleSource {
        public HasExplicitDefaultConstructor() {
        }
    }

    public static class HasStaticFinalField extends RuleSource {
        private static final Object VALUE = null;
    }

    public Iterable<Class<? extends RuleSource>> getDeclaredSources(Class<?> container) {
        try {
            return FluentIterable.from(cache.get(container))
                    .transform(new Function<Reference<Class<? extends RuleSource>>, Class<? extends RuleSource>>() {
                        @Override
                        public Class<? extends RuleSource> apply(Reference<Class<? extends RuleSource>> input) {

    static class InvalidSignature extends RuleSource {
        @Rules
        void broken1(String string, RuleSource ruleSource) {
        }

        @Rules
        void broken2() {
        }

        @Rules
        String broken3(String string) {
            "broken"
        }
    }

    def "rule method must have first parameter that is assignable to RuleSource and have void return type"() {
        when:

A plugin can define rules by extending link:{javadocPath}/org/gradle/model/RuleSource.html[RuleSource] and adding methods that define the rules. The plugin class can either extend link:{javadocPath}/org/gradle/model/RuleSource.html[RuleSource] directly or can implement link:{javadocPath}/org/gradle/api/Plugin.html[Plugin] and include a nested link:{javadocPath}/org/gradle/model/RuleSource.html[RuleSource] subclass.

import java.util.Collections;
import java.util.List;

public class RuleDefinitionRuleExtractor extends AbstractAnnotationDrivenModelRuleExtractor<Rules> {
    private static final ModelType<RuleSource> RULE_SOURCE_MODEL_TYPE = ModelType.of(RuleSource.class);

    @Nullable
    @Override
    public <R, S> ExtractedModelRule registration(MethodRuleDefinition<R, S> ruleDefinition, MethodModelRuleExtractionContext context) {

        static class SourceOne extends RuleSource {}

        static class SourceTwo extends RuleSource {}

        static class NotSource {}
    }

    static class IsASource extends RuleSource {
    }

    static class SourcesNotDeclaredAlphabetically {
        static class B extends RuleSource {}

        static class A extends RuleSource {}
    }

    def "find model rule sources - #clazz"() {

                }
            }

            class EchoRules extends RuleSource {
                @Mutate
                void mutateEcho(Task echo, String message) {
                    echo.message = message
                }
            }

            class Rules extends RuleSource {
                @Model
                String message() {
                    "foo"
                }

     *
     * The ruleSource provides the rule as exactly one rule method annotated with {@link org.gradle.model.Mutate}.
     *
     * This rule method:
     * <ul>
     *     <li>must return void.</li>
     *     <li>must have {@link org.gradle.api.artifacts.ComponentSelection} as its parameter.</li>
     * </ul>
     *
     * @param ruleSource an instance providing a rule implementation
     * @return this

    def "setup"() {
        buildFile << """
        @Managed interface SampleLibrary extends GeneralComponentSpec {}
        @Managed interface SampleBinary extends BinarySpec {}

        class MyComponentBasePlugin extends RuleSource {
            @ComponentType
            void registerLibrary(TypeBuilder<SampleLibrary> builder) {
            }

            @ComponentType
            void registerBinary(TypeBuilder<SampleBinary> builder) {