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/*
* Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/* @test
* @bug 8139885
* @run testng/othervm -ea -esa test.java.lang.invoke.FoldTest
*/
package test.java.lang.invoke;
import java.io.StringWriter;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.invoke.MethodType;
import static java.lang.invoke.MethodType.methodType;
import static org.testng.AssertJUnit.*;
import org.testng.annotations.*;
/**
* Tests for the new fold method handle combinator added in JEP 274.
*/
public class FoldTest {
static final Lookup LOOKUP = MethodHandles.lookup();
@Test
public static void testFold0a() throws Throwable {
// equivalence to foldArguments(MethodHandle,MethodHandle)
MethodHandle fold = MethodHandles.foldArguments(Fold.MH_multer, 0, Fold.MH_adder);
assertEquals(Fold.MT_folded1, fold.type());
assertEquals(720, (int) fold.invoke(3, 4, 5));
}
@Test
public static void testFold1a() throws Throwable {
// test foldArguments for folding position 1
MethodHandle fold = MethodHandles.foldArguments(Fold.MH_multer, 1, Fold.MH_adder1);
assertEquals(Fold.MT_folded1, fold.type());
assertEquals(540, (int) fold.invoke(3, 4, 5));
}
@Test
public static void testFold0b() throws Throwable {
// test foldArguments equivalence with multiple types
MethodHandle fold = MethodHandles.foldArguments(Fold.MH_str, 0, Fold.MH_comb);
assertEquals(Fold.MT_folded2, fold.type());
assertEquals(23, (int) fold.invoke("true", true, 23));
}
@Test
public static void testFold1b() throws Throwable {
// test folgArguments for folding position 1, with multiple types
MethodHandle fold = MethodHandles.foldArguments(Fold.MH_str, 1, Fold.MH_comb2);
assertEquals(Fold.MT_folded3, fold.type());
assertEquals(1, (int) fold.invoke(true, true, 1));
assertEquals(-1, (int) fold.invoke(true, false, -1));
}
@Test
public static void testFoldArgumentsExample() throws Throwable {
// test the JavaDoc foldArguments-with-pos example
StringWriter swr = new StringWriter();
MethodHandle trace = LOOKUP.findVirtual(StringWriter.class, "write", methodType(void.class, String.class)).bindTo(swr);
MethodHandle cat = LOOKUP.findVirtual(String.class, "concat", methodType(String.class, String.class));
assertEquals("boojum", (String) cat.invokeExact("boo", "jum"));
MethodHandle catTrace = MethodHandles.foldArguments(cat, 1, trace);
assertEquals("boojum", (String) catTrace.invokeExact("boo", "jum"));
assertEquals("jum", swr.toString());
}
static class Fold {
static int adder(int a, int b, int c) {
return a + b + c;
}
static int adder1(int a, int b) {
return a + b;
}
static int multer(int x, int q, int r, int s) {
return x * q * r * s;
}
static int str(boolean b1, String s, boolean b2, int x) {
return b1 && s.equals(String.valueOf(b2)) ? x : -x;
}
static boolean comb(String s, boolean b2) {
return !s.equals(b2);
}
static String comb2(boolean b2, int x) {
int ib = b2 ? 1 : 0;
return ib == x ? "true" : "false";
}
static final Class<Fold> FOLD = Fold.class;
static final MethodType MT_adder = methodType(int.class, int.class, int.class, int.class);
static final MethodType MT_adder1 = methodType(int.class, int.class, int.class);
static final MethodType MT_multer = methodType(int.class, int.class, int.class, int.class, int.class);
static final MethodType MT_str = methodType(int.class, boolean.class, String.class, boolean.class, int.class);
static final MethodType MT_comb = methodType(boolean.class, String.class, boolean.class);
static final MethodType MT_comb2 = methodType(String.class, boolean.class, int.class);
static final MethodHandle MH_adder;
static final MethodHandle MH_adder1;
static final MethodHandle MH_multer;
static final MethodHandle MH_str;
static final MethodHandle MH_comb;
static final MethodHandle MH_comb2;
static final MethodType MT_folded1 = methodType(int.class, int.class, int.class, int.class);
static final MethodType MT_folded2 = methodType(int.class, String.class, boolean.class, int.class);
static final MethodType MT_folded3 = methodType(int.class, boolean.class, boolean.class, int.class);
static {
try {
MH_adder = LOOKUP.findStatic(FOLD, "adder", MT_adder);
MH_adder1 = LOOKUP.findStatic(FOLD, "adder1", MT_adder1);
MH_multer = LOOKUP.findStatic(FOLD, "multer", MT_multer);
MH_str = LOOKUP.findStatic(FOLD, "str", MT_str);
MH_comb = LOOKUP.findStatic(FOLD, "comb", MT_comb);
MH_comb2 = LOOKUP.findStatic(FOLD, "comb2", MT_comb2);
} catch (Exception e) {
throw new ExceptionInInitializerError(e);
}
}
}
}
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