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/*
 * @test
 * @run junit DropLookupModeTest
 * @summary Basic unit tests Lookup::dropLookupMode
 */

import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;
import static java.lang.invoke.MethodHandles.Lookup.*;

import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource;
import org.junit.jupiter.params.provider.ValueSource;

public class DropLookupModeTest {

    /**
     * Basic test of dropLookupMode
     */
    @Test
    public void testBasic() {
        final Lookup fullPowerLookup = MethodHandles.lookup();
        final Class<?> lc = fullPowerLookup.lookupClass();
        assertEquals(PUBLIC | MODULE | PACKAGE | PROTECTED | PRIVATE | ORIGINAL, fullPowerLookup.lookupModes());

        Lookup lookup = fullPowerLookup.dropLookupMode(PRIVATE);
        assertSame(lc, lookup.lookupClass());
        assertEquals(PUBLIC | MODULE | PACKAGE, lookup.lookupModes());

        lookup = fullPowerLookup.dropLookupMode(PROTECTED);
        assertSame(lc, lookup.lookupClass());
        assertEquals(PUBLIC | MODULE | PACKAGE | PRIVATE, lookup.lookupModes());

        lookup = fullPowerLookup.dropLookupMode(PACKAGE);
        assertSame(lc, lookup.lookupClass());
        assertEquals(PUBLIC | MODULE, lookup.lookupModes());

        lookup = fullPowerLookup.dropLookupMode(MODULE);
        assertSame(lc, lookup.lookupClass());
        assertEquals(PUBLIC, lookup.lookupModes());

        lookup = fullPowerLookup.dropLookupMode(PUBLIC);
        assertSame(lc, lookup.lookupClass());
        assertEquals(0, lookup.lookupModes());

        lookup = fullPowerLookup.dropLookupMode(UNCONDITIONAL);
        assertSame(lc, lookup.lookupClass());
        assertEquals(PUBLIC | MODULE | PACKAGE | PRIVATE, lookup.lookupModes());
    }

    /**
     * Starting with a full power Lookup, use dropLookupMode to create new Lookups
     * with reduced access.
     */
    @Test
    public void testReducingAccess() {
        Lookup lookup = MethodHandles.lookup();
        final Class<?> lc = lookup.lookupClass();
        assertEquals(PUBLIC | MODULE | PACKAGE | PROTECTED | PRIVATE | ORIGINAL, lookup.lookupModes());

        lookup = lookup.dropLookupMode(PROTECTED);
        assertSame(lc, lookup.lookupClass());
        assertEquals(PUBLIC | MODULE | PACKAGE | PRIVATE, lookup.lookupModes());

        lookup = lookup.dropLookupMode(PRIVATE);
        assertSame(lc, lookup.lookupClass());
        assertEquals(PUBLIC | MODULE | PACKAGE, lookup.lookupModes());

        lookup = lookup.dropLookupMode(PACKAGE);
        assertSame(lc, lookup.lookupClass());
        assertEquals(PUBLIC | MODULE, lookup.lookupModes());

        lookup = lookup.dropLookupMode(MODULE);
        assertSame(lc, lookup.lookupClass());
        assertEquals(PUBLIC, lookup.lookupModes());

        lookup = lookup.dropLookupMode(PUBLIC);
        assertSame(lc, lookup.lookupClass());
        assertEquals(0, lookup.lookupModes());

        // repeat with lookup has no access
        lookup = lookup.dropLookupMode(PUBLIC);
        assertSame(lc, lookup.lookupClass());
        assertEquals(0, lookup.lookupModes());
    }

    public static Object[][] unconditionals() {
        Lookup publicLookup = MethodHandles.publicLookup();
        return new Object[][] {
            { publicLookup, Object.class },
            { publicLookup.in(String.class), String.class },
            { publicLookup.in(DropLookupModeTest.class), DropLookupModeTest.class },
        };
    }

    /**
     * Test dropLookupMode on the lookup with public lookup
     * and UNCONDITIONAL
     */
    @ParameterizedTest
    @MethodSource("unconditionals")
    public void testUnconditionalLookup(Lookup unconditionalLookup, Class<?> expected) {
        assertEquals(UNCONDITIONAL, unconditionalLookup.lookupModes());

        assertPublicLookup(unconditionalLookup.dropLookupMode(PRIVATE), expected);
        assertPublicLookup(unconditionalLookup.dropLookupMode(PROTECTED), expected);
        assertPublicLookup(unconditionalLookup.dropLookupMode(PACKAGE), expected);
        assertPublicLookup(unconditionalLookup.dropLookupMode(MODULE), expected);
        assertPublicLookup(unconditionalLookup.dropLookupMode(PUBLIC), expected);

        // drop all access
        Lookup lookup = unconditionalLookup.dropLookupMode(UNCONDITIONAL);
        assertSame(expected, lookup.lookupClass());
        assertEquals(0, lookup.lookupModes());
    }

    private void assertPublicLookup(Lookup lookup, Class<?> expected) {
        assertSame(expected, lookup.lookupClass());
        assertEquals(UNCONDITIONAL, lookup.lookupModes());
    }

    /**
     * Check that IllegalArgumentException is thrown for bad input
     */
    @ParameterizedTest
    @ValueSource(ints = {
            0,
            (PACKAGE|PRIVATE),    // two modes
            Integer.MAX_VALUE,
            Integer.MIN_VALUE,
    })
    public void testBadInput(int modeToDrop) {
        assertThrows(IllegalArgumentException.class, () -> MethodHandles.lookup().dropLookupMode(modeToDrop));
    }

}