test/jdk/java/lang/invoke/lambda/invokeSpecial/InvokeSpecialMethodTest.java

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/*
 * @test
 * @bug 8274848
 * @run testng InvokeSpecialMethodTest
 * @summary ensure REF_invokeSpecial on a non-private implementation method
 *          behaves as if `super::m` is invoked regardless of its access flag
 */

import org.testng.Assert;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;

import java.lang.invoke.CallSite;
import java.lang.invoke.LambdaMetafactory;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;

import static java.lang.invoke.MethodType.methodType;

public class InvokeSpecialMethodTest {
    static class MethodTest {
        static final Lookup LOOKUP = MethodHandles.lookup();

        public String m_public() {
            return "test_public";
        }

        protected String m_protected() {
            return "test_protected";
        }

        private String m_private() {
            return "test_private";
        }

        public static class SubClass extends MethodTest {
            @Override
            public String m_public() {
                return "subclass_public";
            }

            @Override
            public String m_protected() {
                return "subclass_protected";
            }

            public String m_private() {
                return "subclass_private";
            }
        }

        /*
         * findSpecial with Test class as the special caller matching
         * the factory type `StringFactory(Test)`
         */
        static MethodHandle mh(String name) {
            try {
                return LOOKUP.findSpecial(MethodTest.class, name, methodType(String.class), MethodTest.class);
            } catch (NoSuchMethodException | IllegalAccessException e) {
                throw new RuntimeException(e);
            }
        }

        static final MethodHandle M_PUBLIC = mh("m_public");
        static final MethodHandle M_PROTECTED = mh("m_protected");
        static final MethodHandle M_PRIVATE = mh("m_private");
    }

    @FunctionalInterface
    interface StringFactory {
        String get();
    }

    @DataProvider
    public Object[][] methodProvider() {
        return new Object[][]{
                {MethodTest.M_PUBLIC, "test_public"},
                {MethodTest.M_PROTECTED, "test_protected"},
                {MethodTest.M_PRIVATE, "test_private"}
        };
    }

    @Test(dataProvider = "methodProvider")
    void test(MethodHandle implMethod, String expected) throws Throwable {
        testMetafactory(implMethod, expected);
        testAltMetafactory(implMethod, expected);
    }

    static void testMetafactory(MethodHandle implMethod, String expected) throws Throwable {
        CallSite cs = LambdaMetafactory.metafactory(MethodTest.LOOKUP, "get",
                                                    methodType(StringFactory.class, MethodTest.class),
                                                    methodType(String.class), implMethod, methodType(String.class));
        MethodTest o = new MethodTest.SubClass();
        StringFactory factory = (StringFactory) cs.dynamicInvoker().invokeExact(o);
        String actual = factory.get();
        Assert.assertEquals(actual, expected);
    }

    static void testAltMetafactory(MethodHandle implMethod, String expected) throws Throwable {
        CallSite cs = LambdaMetafactory.altMetafactory(MethodTest.LOOKUP, "get",
                                                       methodType(StringFactory.class, MethodTest.class),
                                                       methodType(String.class), implMethod, methodType(String.class),
                                                       LambdaMetafactory.FLAG_SERIALIZABLE);
        MethodTest o = new MethodTest.SubClass();
        StringFactory factory = (StringFactory) cs.dynamicInvoker().invokeExact(o);
        String actual = factory.get();
        Assert.assertEquals(actual, expected);
    }
}