MethodHandlesCollectArgsTest.java

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/* @test
 * @bug 8259922
 * @run testng/othervm MethodHandlesCollectArgsTest
 */

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

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

import static org.testng.Assert.*;

public class MethodHandlesCollectArgsTest {

    private static final MethodHandle TARGET_II_I = MethodHandles.empty(methodType(int.class, int.class, int.class));
    private static final MethodHandle TARGET__V = MethodHandles.empty(methodType(void.class));
    private static final MethodHandle FILTER_INT = MethodHandles.empty(methodType(int.class, String.class));
    private static final MethodHandle FILTER_VOID = MethodHandles.empty(methodType(void.class, String.class));

    @DataProvider(name = "illegalPos")
    public static Object[][] illegalPos() {
        return new Object[][] {
            {TARGET_II_I, 2, FILTER_INT},
            {TARGET_II_I, 3, FILTER_VOID},
            {TARGET_II_I, -1, FILTER_INT},
            {TARGET_II_I, -1, FILTER_VOID},
            {TARGET__V, 0, FILTER_INT},
            {TARGET__V, 1, FILTER_VOID},
            {TARGET__V, -1, FILTER_VOID},
            {TARGET__V, -1, FILTER_VOID}
        };
    }

    @DataProvider(name = "validPos")
    public static Object[][] validPos() {
        return new Object[][] {
            {TARGET_II_I, 0, FILTER_INT, methodType(int.class, String.class, int.class)},
            {TARGET_II_I, 1, FILTER_INT, methodType(int.class, int.class, String.class)},
            {TARGET_II_I, 0, FILTER_VOID, methodType(int.class, String.class, int.class, int.class)},
            {TARGET_II_I, 1, FILTER_VOID, methodType(int.class, int.class, String.class, int.class)},
            {TARGET_II_I, 2, FILTER_VOID, methodType(int.class, int.class, int.class, String.class)},
            {TARGET__V, 0, FILTER_VOID, methodType(void.class, String.class)}
        };
    }

    @Test(dataProvider="illegalPos", expectedExceptions = {IllegalArgumentException.class})
    public void illegalPosition(MethodHandle target, int position, MethodHandle filter) {
        MethodHandles.collectArguments(target, position, filter);
    }

    @Test(dataProvider="validPos")
    public void legalPosition(MethodHandle target, int position, MethodHandle filter, MethodType expectedType) {
        MethodHandle result = MethodHandles.collectArguments(target, position, filter);
        assertEquals(result.type(), expectedType);
    }
}