| /* |
| * Copyright (c) 2009, 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. |
| * |
| * 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 |
| * @summary example code used in javadoc for java.lang.invoke API |
| * @compile JavaDocExamplesTest.java |
| * @run testng/othervm test.java.lang.invoke.JavaDocExamplesTest |
| */ |
| |
| package test.java.lang.invoke; |
| |
| import java.io.StringWriter; |
| import java.lang.invoke.*; |
| import static java.lang.invoke.MethodHandles.*; |
| import static java.lang.invoke.MethodType.*; |
| |
| import java.util.*; |
| |
| import org.testng.*; |
| import org.testng.annotations.*; |
| |
| /** |
| * @author jrose |
| */ |
| public class JavaDocExamplesTest { |
| /** Wrapper for running the TestNG tests in this module. |
| * Put TestNG on the classpath! |
| */ |
| public static void main(String... ignore) throws Throwable { |
| new JavaDocExamplesTest().run(); |
| } |
| |
| public void run() throws Throwable { |
| testMisc(); |
| testFindStatic(); |
| testFindConstructor(); |
| testFindVirtual(); |
| testFindSpecial(); |
| testPermuteArguments(); |
| testZero(); |
| testDropArguments(); |
| testDropArgumentsToMatch(); |
| testFilterArguments(); |
| testFoldArguments(); |
| testFoldArguments2(); |
| testMethodHandlesSummary(); |
| testAsSpreader(); |
| testAsCollector(); |
| testAsVarargsCollector(); |
| testAsFixedArity(); |
| testAsTypeCornerCases(); |
| testMutableCallSite(); |
| } |
| // How much output? |
| static final Class<?> THIS_CLASS = JavaDocExamplesTest.class; |
| static int verbosity = Integer.getInteger(THIS_CLASS.getSimpleName()+".verbosity", 0); |
| |
| |
| {} |
| private static final Lookup LOOKUP = lookup(); |
| // static final private MethodHandle CONCAT_1 = LOOKUP.findVirtual(String.class, |
| // "concat", methodType(String.class, String.class)); |
| // static final private MethodHandle HASHCODE_1 = LOOKUP.findVirtual(Object.class, |
| // "hashCode", methodType(int.class)); |
| |
| // form required if ReflectiveOperationException is intercepted: |
| private static final MethodHandle CONCAT_2, HASHCODE_2, ADD_2, SUB_2; |
| static { |
| try { |
| Class<?> THIS_CLASS = LOOKUP.lookupClass(); |
| CONCAT_2 = LOOKUP.findVirtual(String.class, |
| "concat", methodType(String.class, String.class)); |
| HASHCODE_2 = LOOKUP.findVirtual(Object.class, |
| "hashCode", methodType(int.class)); |
| ADD_2 = LOOKUP.findStatic(THIS_CLASS, "add", methodType(int.class, int.class, int.class)); |
| SUB_2 = LOOKUP.findStatic(THIS_CLASS, "sub", methodType(int.class, int.class, int.class)); |
| } catch (ReflectiveOperationException ex) { |
| throw new RuntimeException(ex); |
| } |
| } |
| static int add(int x, int y) { return x + y; } |
| static int sub(int x, int y) { return x - y; } |
| |
| {} |
| |
| @Test public void testMisc() throws Throwable { |
| // Extra tests, not from javadoc: |
| {} |
| MethodHandle CONCAT_3 = LOOKUP.findVirtual(String.class, |
| "concat", methodType(String.class, String.class)); |
| MethodHandle HASHCODE_3 = LOOKUP.findVirtual(Object.class, |
| "hashCode", methodType(int.class)); |
| //assertEquals("xy", (String) CONCAT_1.invokeExact("x", "y")); |
| assertEquals("xy", (String) CONCAT_2.invokeExact("x", "y")); |
| assertEquals("xy", (String) CONCAT_3.invokeExact("x", "y")); |
| //assertEquals("xy".hashCode(), (int) HASHCODE_1.invokeExact((Object)"xy")); |
| assertEquals("xy".hashCode(), (int) HASHCODE_2.invokeExact((Object)"xy")); |
| assertEquals("xy".hashCode(), (int) HASHCODE_3.invokeExact((Object)"xy")); |
| {} |
| } |
| |
| @Test public void testFindStatic() throws Throwable { |
| {} |
| MethodHandle MH_asList = publicLookup().findStatic(Arrays.class, |
| "asList", methodType(List.class, Object[].class)); |
| assertEquals("[x, y]", MH_asList.invoke("x", "y").toString()); |
| {} |
| } |
| |
| @Test public void testFindVirtual() throws Throwable { |
| {} |
| MethodHandle MH_concat = publicLookup().findVirtual(String.class, |
| "concat", methodType(String.class, String.class)); |
| MethodHandle MH_hashCode = publicLookup().findVirtual(Object.class, |
| "hashCode", methodType(int.class)); |
| MethodHandle MH_hashCode_String = publicLookup().findVirtual(String.class, |
| "hashCode", methodType(int.class)); |
| assertEquals("xy", (String) MH_concat.invokeExact("x", "y")); |
| assertEquals("xy".hashCode(), (int) MH_hashCode.invokeExact((Object)"xy")); |
| assertEquals("xy".hashCode(), (int) MH_hashCode_String.invokeExact("xy")); |
| // interface method: |
| MethodHandle MH_subSequence = publicLookup().findVirtual(CharSequence.class, |
| "subSequence", methodType(CharSequence.class, int.class, int.class)); |
| assertEquals("def", MH_subSequence.invoke("abcdefghi", 3, 6).toString()); |
| // constructor "internal method" must be accessed differently: |
| MethodType MT_newString = methodType(void.class); //()V for new String() |
| try { assertEquals("impossible", lookup() |
| .findVirtual(String.class, "<init>", MT_newString)); |
| } catch (NoSuchMethodException ex) { } // OK |
| MethodHandle MH_newString = publicLookup() |
| .findConstructor(String.class, MT_newString); |
| assertEquals("", (String) MH_newString.invokeExact()); |
| {} |
| } |
| |
| @Test public void testFindConstructor() throws Throwable { |
| {} |
| MethodHandle MH_newArrayList = publicLookup().findConstructor( |
| ArrayList.class, methodType(void.class, Collection.class)); |
| Collection orig = Arrays.asList("x", "y"); |
| Collection copy = (ArrayList) MH_newArrayList.invokeExact(orig); |
| assert(orig != copy); |
| assertEquals(orig, copy); |
| // a variable-arity constructor: |
| MethodHandle MH_newProcessBuilder = publicLookup().findConstructor( |
| ProcessBuilder.class, methodType(void.class, String[].class)); |
| ProcessBuilder pb = (ProcessBuilder) |
| MH_newProcessBuilder.invoke("x", "y", "z"); |
| assertEquals("[x, y, z]", pb.command().toString()); |
| {} |
| } |
| |
| // for testFindSpecial |
| {} |
| static class Listie extends ArrayList { |
| public String toString() { return "[wee Listie]"; } |
| static Lookup lookup() { return MethodHandles.lookup(); } |
| } |
| {} |
| |
| @Test public void testFindSpecial() throws Throwable { |
| {} |
| // no access to constructor via invokeSpecial: |
| MethodHandle MH_newListie = Listie.lookup() |
| .findConstructor(Listie.class, methodType(void.class)); |
| Listie l = (Listie) MH_newListie.invokeExact(); |
| try { assertEquals("impossible", Listie.lookup().findSpecial( |
| Listie.class, "<init>", methodType(void.class), Listie.class)); |
| } catch (NoSuchMethodException ex) { } // OK |
| // access to super and self methods via invokeSpecial: |
| MethodHandle MH_super = Listie.lookup().findSpecial( |
| ArrayList.class, "toString" , methodType(String.class), Listie.class); |
| MethodHandle MH_this = Listie.lookup().findSpecial( |
| Listie.class, "toString" , methodType(String.class), Listie.class); |
| MethodHandle MH_duper = Listie.lookup().findSpecial( |
| Object.class, "toString" , methodType(String.class), Listie.class); |
| assertEquals("[]", (String) MH_super.invokeExact(l)); |
| assertEquals(""+l, (String) MH_this.invokeExact(l)); |
| assertEquals("[]", (String) MH_duper.invokeExact(l)); // ArrayList method |
| try { assertEquals("inaccessible", Listie.lookup().findSpecial( |
| String.class, "toString", methodType(String.class), Listie.class)); |
| } catch (IllegalAccessException ex) { } // OK |
| Listie subl = new Listie() { public String toString() { return "[subclass]"; } }; |
| assertEquals(""+l, (String) MH_this.invokeExact(subl)); // Listie method |
| {} |
| } |
| |
| @Test public void testPermuteArguments() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodType intfn1 = methodType(int.class, int.class); |
| MethodType intfn2 = methodType(int.class, int.class, int.class); |
| MethodHandle sub = SUB_2;// ... {int x, int y => x-y} ...; |
| assert(sub.type().equals(intfn2)); |
| MethodHandle sub1 = permuteArguments(sub, intfn2, 0, 1); |
| MethodHandle rsub = permuteArguments(sub, intfn2, 1, 0); |
| assert((int)rsub.invokeExact(1, 100) == 99); |
| MethodHandle add = ADD_2;// ... {int x, int y => x+y} ...; |
| assert(add.type().equals(intfn2)); |
| MethodHandle twice = permuteArguments(add, intfn1, 0, 0); |
| assert(twice.type().equals(intfn1)); |
| assert((int)twice.invokeExact(21) == 42); |
| }} |
| {{ |
| {} /// JAVADOC |
| MethodHandle cat = lookup().findVirtual(String.class, |
| "concat", methodType(String.class, String.class)); |
| assertEquals("xy", (String) cat.invokeExact("x", "y")); |
| MethodHandle d0 = dropArguments(cat, 0, String.class); |
| assertEquals("yz", (String) d0.invokeExact("x", "y", "z")); |
| MethodHandle d1 = dropArguments(cat, 1, String.class); |
| assertEquals("xz", (String) d1.invokeExact("x", "y", "z")); |
| MethodHandle d2 = dropArguments(cat, 2, String.class); |
| assertEquals("xy", (String) d2.invokeExact("x", "y", "z")); |
| MethodHandle d12 = dropArguments(cat, 1, int.class, boolean.class); |
| assertEquals("xz", (String) d12.invokeExact("x", 12, true, "z")); |
| }} |
| } |
| |
| @Test public void testZero() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| Class<?> type = Double.class; |
| MethodHandle mh1 = MethodHandles.explicitCastArguments(MethodHandles.constant(Object.class, null), methodType(type)); |
| assertEquals("()Double", mh1.type().toString()); |
| MethodHandle mh2 = MethodHandles.empty(methodType(type)); |
| assertEquals("()Double", mh2.type().toString()); |
| }} |
| } |
| |
| @Test public void testDropArguments() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle cat = lookup().findVirtual(String.class, |
| "concat", methodType(String.class, String.class)); |
| assertEquals("xy", (String) cat.invokeExact("x", "y")); |
| MethodType bigType = cat.type().insertParameterTypes(0, int.class, String.class); |
| MethodHandle d0 = dropArguments(cat, 0, bigType.parameterList().subList(0,2)); |
| assertEquals(bigType, d0.type()); |
| assertEquals("yz", (String) d0.invokeExact(123, "x", "y", "z")); |
| }} |
| {{ |
| {} /// JAVADOC |
| MethodHandle cat = lookup().findVirtual(String.class, |
| "concat", methodType(String.class, String.class)); |
| assertEquals("xy", (String) cat.invokeExact("x", "y")); |
| MethodHandle d0 = dropArguments(cat, 0, String.class); |
| assertEquals("yz", (String) d0.invokeExact("x", "y", "z")); |
| MethodHandle d1 = dropArguments(cat, 1, String.class); |
| assertEquals("xz", (String) d1.invokeExact("x", "y", "z")); |
| MethodHandle d2 = dropArguments(cat, 2, String.class); |
| assertEquals("xy", (String) d2.invokeExact("x", "y", "z")); |
| MethodHandle d12 = dropArguments(cat, 1, int.class, boolean.class); |
| assertEquals("xz", (String) d12.invokeExact("x", 12, true, "z")); |
| }} |
| } |
| |
| @Test public void testDropArgumentsToMatch() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle h0= constant(boolean.class, true); |
| MethodHandle h1 = lookup().findVirtual(String.class, "concat", methodType(String.class, String.class)); |
| MethodType bigType = h1.type().insertParameterTypes(1, String.class, int.class); |
| MethodHandle h2 = dropArguments(h1, 0, bigType.parameterList()); |
| if (h1.type().parameterCount() < h2.type().parameterCount()) { |
| h1 = dropArgumentsToMatch(h1, 0, h2.type().parameterList(), 0); // lengthen h1 |
| } |
| else { |
| h2 = dropArgumentsToMatch(h2, 0, h1.type().parameterList(), 0); // lengthen h2 |
| } |
| MethodHandle h3 = guardWithTest(h0, h1, h2); |
| assertEquals("xy", h3.invoke("x", "y", 1, "a", "b", "c")); |
| }} |
| } |
| |
| @Test public void testFilterArguments() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle cat = lookup().findVirtual(String.class, |
| "concat", methodType(String.class, String.class)); |
| MethodHandle upcase = lookup().findVirtual(String.class, |
| "toUpperCase", methodType(String.class)); |
| assertEquals("xy", (String) cat.invokeExact("x", "y")); |
| MethodHandle f0 = filterArguments(cat, 0, upcase); |
| assertEquals("Xy", (String) f0.invokeExact("x", "y")); // Xy |
| MethodHandle f1 = filterArguments(cat, 1, upcase); |
| assertEquals("xY", (String) f1.invokeExact("x", "y")); // xY |
| MethodHandle f2 = filterArguments(cat, 0, upcase, upcase); |
| assertEquals("XY", (String) f2.invokeExact("x", "y")); // XY |
| }} |
| } |
| |
| @Test public void testCollectArguments() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle deepToString = publicLookup() |
| .findStatic(Arrays.class, "deepToString", methodType(String.class, Object[].class)); |
| MethodHandle ts1 = deepToString.asCollector(String[].class, 1); |
| assertEquals("[strange]", (String) ts1.invokeExact("strange")); |
| MethodHandle ts2 = deepToString.asCollector(String[].class, 2); |
| assertEquals("[up, down]", (String) ts2.invokeExact("up", "down")); |
| MethodHandle ts3 = deepToString.asCollector(String[].class, 3); |
| MethodHandle ts3_ts2 = collectArguments(ts3, 1, ts2); |
| assertEquals("[top, [up, down], strange]", |
| (String) ts3_ts2.invokeExact("top", "up", "down", "strange")); |
| MethodHandle ts3_ts2_ts1 = collectArguments(ts3_ts2, 3, ts1); |
| assertEquals("[top, [up, down], [strange]]", |
| (String) ts3_ts2_ts1.invokeExact("top", "up", "down", "strange")); |
| MethodHandle ts3_ts2_ts3 = collectArguments(ts3_ts2, 1, ts3); |
| assertEquals("[top, [[up, down, strange], charm], bottom]", |
| (String) ts3_ts2_ts3.invokeExact("top", "up", "down", "strange", "charm", "bottom")); |
| }} |
| } |
| |
| @Test public void testFoldArguments() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle trace = publicLookup().findVirtual(java.io.PrintStream.class, |
| "println", methodType(void.class, String.class)) |
| .bindTo(System.out); |
| MethodHandle cat = lookup().findVirtual(String.class, |
| "concat", methodType(String.class, String.class)); |
| assertEquals("boojum", (String) cat.invokeExact("boo", "jum")); |
| MethodHandle catTrace = foldArguments(cat, trace); |
| // also prints "boo": |
| assertEquals("boojum", (String) catTrace.invokeExact("boo", "jum")); |
| }} |
| } |
| |
| static void assertEquals(Object exp, Object act) { |
| if (verbosity > 0) |
| System.out.println("result: "+act); |
| Assert.assertEquals(exp, act); |
| } |
| |
| static void assertTrue(boolean b) { |
| if (verbosity > 0) { |
| System.out.println("result: " + b); |
| } |
| Assert.assertTrue(b); |
| } |
| |
| @Test public void testMethodHandlesSummary() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| Object x, y; String s; int i; |
| MethodType mt; MethodHandle mh; |
| MethodHandles.Lookup lookup = MethodHandles.lookup(); |
| // mt is (char,char)String |
| mt = MethodType.methodType(String.class, char.class, char.class); |
| mh = lookup.findVirtual(String.class, "replace", mt); |
| s = (String) mh.invokeExact("daddy",'d','n'); |
| // invokeExact(Ljava/lang/String;CC)Ljava/lang/String; |
| assertEquals(s, "nanny"); |
| // weakly typed invocation (using MHs.invoke) |
| s = (String) mh.invokeWithArguments("sappy", 'p', 'v'); |
| assertEquals(s, "savvy"); |
| // mt is (Object[])List |
| mt = MethodType.methodType(java.util.List.class, Object[].class); |
| mh = lookup.findStatic(java.util.Arrays.class, "asList", mt); |
| assert(mh.isVarargsCollector()); |
| x = mh.invoke("one", "two"); |
| // invoke(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/Object; |
| assertEquals(x, java.util.Arrays.asList("one","two")); |
| // mt is (Object,Object,Object)Object |
| mt = MethodType.genericMethodType(3); |
| mh = mh.asType(mt); |
| x = mh.invokeExact((Object)1, (Object)2, (Object)3); |
| // invokeExact(Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object; |
| assertEquals(x, java.util.Arrays.asList(1,2,3)); |
| // mt is ()int |
| mt = MethodType.methodType(int.class); |
| mh = lookup.findVirtual(java.util.List.class, "size", mt); |
| i = (int) mh.invokeExact(java.util.Arrays.asList(1,2,3)); |
| // invokeExact(Ljava/util/List;)I |
| assert(i == 3); |
| mt = MethodType.methodType(void.class, String.class); |
| mh = lookup.findVirtual(java.io.PrintStream.class, "println", mt); |
| mh.invokeExact(System.out, "Hello, world."); |
| // invokeExact(Ljava/io/PrintStream;Ljava/lang/String;)V |
| {} |
| }} |
| } |
| |
| @Test public void testAsSpreader() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle equals = publicLookup() |
| .findVirtual(String.class, "equals", methodType(boolean.class, Object.class)); |
| assert( (boolean) equals.invokeExact("me", (Object)"me")); |
| assert(!(boolean) equals.invokeExact("me", (Object)"thee")); |
| // spread both arguments from a 2-array: |
| MethodHandle eq2 = equals.asSpreader(Object[].class, 2); |
| assert( (boolean) eq2.invokeExact(new Object[]{ "me", "me" })); |
| assert(!(boolean) eq2.invokeExact(new Object[]{ "me", "thee" })); |
| // try to spread from anything but a 2-array: |
| for (int n = 0; n <= 10; n++) { |
| Object[] badArityArgs = (n == 2 ? null : new Object[n]); |
| try { assert((boolean) eq2.invokeExact(badArityArgs) && false); } |
| catch (IllegalArgumentException ex) { } // OK |
| } |
| // spread both arguments from a String array: |
| MethodHandle eq2s = equals.asSpreader(String[].class, 2); |
| assert( (boolean) eq2s.invokeExact(new String[]{ "me", "me" })); |
| assert(!(boolean) eq2s.invokeExact(new String[]{ "me", "thee" })); |
| // spread second arguments from a 1-array: |
| MethodHandle eq1 = equals.asSpreader(Object[].class, 1); |
| assert( (boolean) eq1.invokeExact("me", new Object[]{ "me" })); |
| assert(!(boolean) eq1.invokeExact("me", new Object[]{ "thee" })); |
| // spread no arguments from a 0-array or null: |
| MethodHandle eq0 = equals.asSpreader(Object[].class, 0); |
| assert( (boolean) eq0.invokeExact("me", (Object)"me", new Object[0])); |
| assert(!(boolean) eq0.invokeExact("me", (Object)"thee", (Object[])null)); |
| // asSpreader and asCollector are approximate inverses: |
| for (int n = 0; n <= 2; n++) { |
| for (Class<?> a : new Class<?>[]{Object[].class, String[].class, CharSequence[].class}) { |
| MethodHandle equals2 = equals.asSpreader(a, n).asCollector(a, n); |
| assert( (boolean) equals2.invokeWithArguments("me", "me")); |
| assert(!(boolean) equals2.invokeWithArguments("me", "thee")); |
| } |
| } |
| MethodHandle caToString = publicLookup() |
| .findStatic(Arrays.class, "toString", methodType(String.class, char[].class)); |
| assertEquals("[A, B, C]", (String) caToString.invokeExact("ABC".toCharArray())); |
| MethodHandle caString3 = caToString.asCollector(char[].class, 3); |
| assertEquals("[A, B, C]", (String) caString3.invokeExact('A', 'B', 'C')); |
| MethodHandle caToString2 = caString3.asSpreader(char[].class, 2); |
| assertEquals("[A, B, C]", (String) caToString2.invokeExact('A', "BC".toCharArray())); |
| }} |
| } |
| |
| @Test public void testAsCollector() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle deepToString = publicLookup() |
| .findStatic(Arrays.class, "deepToString", methodType(String.class, Object[].class)); |
| assertEquals("[won]", (String) deepToString.invokeExact(new Object[]{"won"})); |
| MethodHandle ts1 = deepToString.asCollector(Object[].class, 1); |
| assertEquals(methodType(String.class, Object.class), ts1.type()); |
| //assertEquals("[won]", (String) ts1.invokeExact( new Object[]{"won"})); //FAIL |
| assertEquals("[[won]]", (String) ts1.invokeExact((Object) new Object[]{"won"})); |
| // arrayType can be a subtype of Object[] |
| MethodHandle ts2 = deepToString.asCollector(String[].class, 2); |
| assertEquals(methodType(String.class, String.class, String.class), ts2.type()); |
| assertEquals("[two, too]", (String) ts2.invokeExact("two", "too")); |
| MethodHandle ts0 = deepToString.asCollector(Object[].class, 0); |
| assertEquals("[]", (String) ts0.invokeExact()); |
| // collectors can be nested, Lisp-style |
| MethodHandle ts22 = deepToString.asCollector(Object[].class, 3).asCollector(String[].class, 2); |
| assertEquals("[A, B, [C, D]]", ((String) ts22.invokeExact((Object)'A', (Object)"B", "C", "D"))); |
| // arrayType can be any primitive array type |
| MethodHandle bytesToString = publicLookup() |
| .findStatic(Arrays.class, "toString", methodType(String.class, byte[].class)) |
| .asCollector(byte[].class, 3); |
| assertEquals("[1, 2, 3]", (String) bytesToString.invokeExact((byte)1, (byte)2, (byte)3)); |
| MethodHandle longsToString = publicLookup() |
| .findStatic(Arrays.class, "toString", methodType(String.class, long[].class)) |
| .asCollector(long[].class, 1); |
| assertEquals("[123]", (String) longsToString.invokeExact((long)123)); |
| }} |
| } |
| |
| @SuppressWarnings("rawtypes") |
| @Test public void testAsVarargsCollector() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle deepToString = publicLookup() |
| .findStatic(Arrays.class, "deepToString", methodType(String.class, Object[].class)); |
| MethodHandle ts1 = deepToString.asVarargsCollector(Object[].class); |
| assertEquals("[won]", (String) ts1.invokeExact( new Object[]{"won"})); |
| assertEquals("[won]", (String) ts1.invoke( new Object[]{"won"})); |
| assertEquals("[won]", (String) ts1.invoke( "won" )); |
| assertEquals("[[won]]", (String) ts1.invoke((Object) new Object[]{"won"})); |
| // findStatic of Arrays.asList(...) produces a variable arity method handle: |
| MethodHandle asList = publicLookup() |
| .findStatic(Arrays.class, "asList", methodType(List.class, Object[].class)); |
| assertEquals(methodType(List.class, Object[].class), asList.type()); |
| assert(asList.isVarargsCollector()); |
| assertEquals("[]", asList.invoke().toString()); |
| assertEquals("[1]", asList.invoke(1).toString()); |
| assertEquals("[two, too]", asList.invoke("two", "too").toString()); |
| String[] argv = { "three", "thee", "tee" }; |
| assertEquals("[three, thee, tee]", asList.invoke(argv).toString()); |
| assertEquals("[three, thee, tee]", asList.invoke((Object[])argv).toString()); |
| List ls = (List) asList.invoke((Object)argv); |
| assertEquals(1, ls.size()); |
| assertEquals("[three, thee, tee]", Arrays.toString((Object[])ls.get(0))); |
| }} |
| } |
| |
| @Test public void testAsFixedArity() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle asListVar = publicLookup() |
| .findStatic(Arrays.class, "asList", methodType(List.class, Object[].class)) |
| .asVarargsCollector(Object[].class); |
| MethodHandle asListFix = asListVar.asFixedArity(); |
| assertEquals("[1]", asListVar.invoke(1).toString()); |
| Exception caught = null; |
| try { asListFix.invoke((Object)1); } |
| catch (Exception ex) { caught = ex; } |
| assert(caught instanceof ClassCastException); |
| assertEquals("[two, too]", asListVar.invoke("two", "too").toString()); |
| try { asListFix.invoke("two", "too"); } |
| catch (Exception ex) { caught = ex; } |
| assert(caught instanceof WrongMethodTypeException); |
| Object[] argv = { "three", "thee", "tee" }; |
| assertEquals("[three, thee, tee]", asListVar.invoke(argv).toString()); |
| assertEquals("[three, thee, tee]", asListFix.invoke(argv).toString()); |
| assertEquals(1, ((List) asListVar.invoke((Object)argv)).size()); |
| assertEquals("[three, thee, tee]", asListFix.invoke((Object)argv).toString()); |
| }} |
| } |
| |
| @Test public void testAsTypeCornerCases() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle i2s = publicLookup() |
| .findVirtual(Integer.class, "toString", methodType(String.class)); |
| i2s = i2s.asType(i2s.type().unwrap()); |
| MethodHandle l2s = publicLookup() |
| .findVirtual(Long.class, "toString", methodType(String.class)); |
| l2s = l2s.asType(l2s.type().unwrap()); |
| |
| Exception caught = null; |
| try { i2s.asType(methodType(String.class, String.class)); } |
| catch (Exception ex) { caught = ex; } |
| assert(caught instanceof WrongMethodTypeException); |
| |
| i2s.asType(methodType(String.class, byte.class)); |
| i2s.asType(methodType(String.class, Byte.class)); |
| i2s.asType(methodType(String.class, Character.class)); |
| i2s.asType(methodType(String.class, Integer.class)); |
| l2s.asType(methodType(String.class, byte.class)); |
| l2s.asType(methodType(String.class, Byte.class)); |
| l2s.asType(methodType(String.class, Character.class)); |
| l2s.asType(methodType(String.class, Integer.class)); |
| l2s.asType(methodType(String.class, Long.class)); |
| |
| caught = null; |
| try { i2s.asType(methodType(String.class, Long.class)); } |
| catch (Exception ex) { caught = ex; } |
| assert(caught instanceof WrongMethodTypeException); |
| |
| MethodHandle i2sGen = i2s.asType(methodType(String.class, Object.class)); |
| MethodHandle l2sGen = l2s.asType(methodType(String.class, Object.class)); |
| |
| i2sGen.invoke(42); // int -> Integer -> Object -> Integer -> int |
| i2sGen.invoke((byte)4); // byte -> Byte -> Object -> Byte -> byte -> int |
| l2sGen.invoke(42); // int -> Integer -> Object -> Integer -> int |
| l2sGen.invoke((byte)4); // byte -> Byte -> Object -> Byte -> byte -> int |
| l2sGen.invoke(0x420000000L); |
| |
| caught = null; |
| try { i2sGen.invoke(0x420000000L); } // long -> Long -> Object -> Integer CCE |
| catch (Exception ex) { caught = ex; } |
| assert(caught instanceof ClassCastException); |
| |
| caught = null; |
| try { i2sGen.invoke("asdf"); } // String -> Object -> Integer CCE |
| catch (Exception ex) { caught = ex; } |
| assert(caught instanceof ClassCastException); |
| {} |
| }} |
| } |
| |
| @Test public void testMutableCallSite() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MutableCallSite name = new MutableCallSite(MethodType.methodType(String.class)); |
| MethodHandle MH_name = name.dynamicInvoker(); |
| MethodType MT_str1 = MethodType.methodType(String.class); |
| MethodHandle MH_upcase = MethodHandles.lookup() |
| .findVirtual(String.class, "toUpperCase", MT_str1); |
| MethodHandle worker1 = MethodHandles.filterReturnValue(MH_name, MH_upcase); |
| name.setTarget(MethodHandles.constant(String.class, "Rocky")); |
| assertEquals("ROCKY", (String) worker1.invokeExact()); |
| name.setTarget(MethodHandles.constant(String.class, "Fred")); |
| assertEquals("FRED", (String) worker1.invokeExact()); |
| // (mutation can be continued indefinitely) |
| /* |
| * </pre></blockquote> |
| * <p> |
| * The same call site may be used in several places at once. |
| * <blockquote><pre> |
| */ |
| MethodType MT_str2 = MethodType.methodType(String.class, String.class); |
| MethodHandle MH_cat = lookup().findVirtual(String.class, |
| "concat", methodType(String.class, String.class)); |
| MethodHandle MH_dear = MethodHandles.insertArguments(MH_cat, 1, ", dear?"); |
| MethodHandle worker2 = MethodHandles.filterReturnValue(MH_name, MH_dear); |
| assertEquals("Fred, dear?", (String) worker2.invokeExact()); |
| name.setTarget(MethodHandles.constant(String.class, "Wilma")); |
| assertEquals("WILMA", (String) worker1.invokeExact()); |
| assertEquals("Wilma, dear?", (String) worker2.invokeExact()); |
| {} |
| }} |
| } |
| |
| @Test public void testSwitchPoint() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle MH_strcat = MethodHandles.lookup() |
| .findVirtual(String.class, "concat", MethodType.methodType(String.class, String.class)); |
| SwitchPoint spt = new SwitchPoint(); |
| assert(!spt.hasBeenInvalidated()); |
| // the following steps may be repeated to re-use the same switch point: |
| MethodHandle worker1 = MH_strcat; |
| MethodHandle worker2 = MethodHandles.permuteArguments(MH_strcat, MH_strcat.type(), 1, 0); |
| MethodHandle worker = spt.guardWithTest(worker1, worker2); |
| assertEquals("method", (String) worker.invokeExact("met", "hod")); |
| SwitchPoint.invalidateAll(new SwitchPoint[]{ spt }); |
| assert(spt.hasBeenInvalidated()); |
| assertEquals("hodmet", (String) worker.invokeExact("met", "hod")); |
| {} |
| }} |
| } |
| |
| @Test public void testFoldArguments2() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| // argument-based dispatch for methods of the form boolean x.___(y: String) |
| Lookup lookup = publicLookup(); |
| // first, a tracing hack: |
| MethodHandle println = lookup.findVirtual(java.io.PrintStream.class, "println", methodType(void.class, String.class)); |
| MethodHandle arrayToString = lookup.findStatic(Arrays.class, "toString", methodType(String.class, Object[].class)); |
| MethodHandle concat = lookup.findVirtual(String.class, "concat", methodType(String.class, String.class)); |
| MethodHandle arrayToString_DIS = filterReturnValue(arrayToString, concat.bindTo("DIS:")); |
| MethodHandle arrayToString_INV = filterReturnValue(arrayToString, concat.bindTo("INV:")); |
| MethodHandle printArgs_DIS = filterReturnValue(arrayToString_DIS, println.bindTo(System.out)).asVarargsCollector(Object[].class); |
| MethodHandle printArgs_INV = filterReturnValue(arrayToString_INV, println.bindTo(System.out)).asVarargsCollector(Object[].class); |
| // metaobject protocol: |
| MethodType mtype = methodType(boolean.class, String.class); |
| MethodHandle findVirtual = lookup.findVirtual(Lookup.class, |
| "findVirtual", methodType(MethodHandle.class, Class.class, String.class, MethodType.class)); |
| MethodHandle getClass = lookup.findVirtual(Object.class, |
| "getClass", methodType(Class.class)); |
| MethodHandle dispatch = findVirtual; |
| dispatch = filterArguments(dispatch, 1, getClass); |
| dispatch = insertArguments(dispatch, 3, mtype); |
| dispatch = dispatch.bindTo(lookup); |
| assertEquals(methodType(MethodHandle.class, Object.class, String.class), dispatch.type()); |
| MethodHandle invoker = invoker(mtype.insertParameterTypes(0, Object.class)); |
| // wrap tracing around the dispatch and invoke steps: |
| dispatch = foldArguments(dispatch, printArgs_DIS.asType(dispatch.type().changeReturnType(void.class))); |
| invoker = foldArguments(invoker, printArgs_INV.asType(invoker.type().changeReturnType(void.class))); |
| invoker = dropArguments(invoker, 2, String.class); // ignore selector |
| // compose the dispatcher and the invoker: |
| MethodHandle invokeDispatched = foldArguments(invoker, dispatch); |
| Object x = "football", y = new java.util.Scanner("bar"); |
| assert( (boolean) invokeDispatched.invokeExact(x, "startsWith", "foo")); |
| assert(!(boolean) invokeDispatched.invokeExact(x, "startsWith", "#")); |
| assert( (boolean) invokeDispatched.invokeExact(x, "endsWith", "all")); |
| assert(!(boolean) invokeDispatched.invokeExact(x, "endsWith", "foo")); |
| assert( (boolean) invokeDispatched.invokeExact(y, "hasNext", "[abc]+[rst]")); |
| assert(!(boolean) invokeDispatched.invokeExact(y, "hasNext", "[123]+[789]")); |
| }} |
| } |
| |
| static int one(int k) { return 1; } |
| static int inc(int i, int acc, int k) { return i + 1; } |
| static int mult(int i, int acc, int k) { return i * acc; } |
| static boolean pred(int i, int acc, int k) { return i < k; } |
| static int fin(int i, int acc, int k) { return acc; } |
| |
| @Test public void testLoop() throws Throwable { |
| MethodHandle MH_inc, MH_one, MH_mult, MH_pred, MH_fin; |
| Class<?> I = int.class; |
| MH_inc = LOOKUP.findStatic(THIS_CLASS, "inc", methodType(I, I, I, I)); |
| MH_one = LOOKUP.findStatic(THIS_CLASS, "one", methodType(I, I)); |
| MH_mult = LOOKUP.findStatic(THIS_CLASS, "mult", methodType(I, I, I, I)); |
| MH_pred = LOOKUP.findStatic(THIS_CLASS, "pred", methodType(boolean.class, I, I, I)); |
| MH_fin = LOOKUP.findStatic(THIS_CLASS, "fin", methodType(I, I, I, I)); |
| {{ |
| {} /// JAVADOC |
| // iterative implementation of the factorial function as a loop handle |
| // null initializer for counter, should initialize to 0 |
| MethodHandle[] counterClause = new MethodHandle[]{null, MH_inc}; |
| MethodHandle[] accumulatorClause = new MethodHandle[]{MH_one, MH_mult, MH_pred, MH_fin}; |
| MethodHandle loop = MethodHandles.loop(counterClause, accumulatorClause); |
| assertEquals(120, loop.invoke(5)); |
| {} |
| }} |
| } |
| |
| static List<String> initZip(Iterator<String> a, Iterator<String> b) { return new ArrayList<>(); } |
| static boolean zipPred(List<String> zip, Iterator<String> a, Iterator<String> b) { return a.hasNext() && b.hasNext(); } |
| static List<String> zipStep(List<String> zip, Iterator<String> a, Iterator<String> b) { |
| zip.add(a.next()); |
| zip.add(b.next()); |
| return zip; |
| } |
| |
| @Test public void testWhileLoop() throws Throwable { |
| MethodHandle MH_initZip, MH_zipPred, MH_zipStep; |
| Class<?> IT = Iterator.class; |
| Class<?> L = List.class; |
| MH_initZip = LOOKUP.findStatic(THIS_CLASS, "initZip", methodType(L, IT, IT)); |
| MH_zipPred = LOOKUP.findStatic(THIS_CLASS, "zipPred", methodType(boolean.class, L, IT, IT)); |
| MH_zipStep = LOOKUP.findStatic(THIS_CLASS, "zipStep", methodType(L, L, IT, IT)); |
| {{ |
| {} /// JAVADOC |
| // implement the zip function for lists as a loop handle |
| MethodHandle loop = MethodHandles.whileLoop(MH_initZip, MH_zipPred, MH_zipStep); |
| List<String> a = Arrays.asList("a", "b", "c", "d"); |
| List<String> b = Arrays.asList("e", "f", "g", "h"); |
| List<String> zipped = Arrays.asList("a", "e", "b", "f", "c", "g", "d", "h"); |
| assertEquals(zipped, (List<String>) loop.invoke(a.iterator(), b.iterator())); |
| {} |
| }} |
| } |
| |
| static int zero(int limit) { return 0; } |
| static int step(int i, int limit) { return i + 1; } |
| static boolean pred(int i, int limit) { return i < limit; } |
| |
| @Test public void testDoWhileLoop() throws Throwable { |
| MethodHandle MH_zero, MH_step, MH_pred; |
| Class<?> I = int.class; |
| MH_zero = LOOKUP.findStatic(THIS_CLASS, "zero", methodType(I, I)); |
| MH_step = LOOKUP.findStatic(THIS_CLASS, "step", methodType(I, I, I)); |
| MH_pred = LOOKUP.findStatic(THIS_CLASS, "pred", methodType(boolean.class, I, I)); |
| {{ |
| {} /// JAVADOC |
| // int i = 0; while (i < limit) { ++i; } return i; => limit |
| MethodHandle loop = MethodHandles.doWhileLoop(MH_zero, MH_step, MH_pred); |
| assertEquals(23, loop.invoke(23)); |
| {} |
| }} |
| } |
| |
| static String start(String arg) { return arg; } |
| static String step(int counter, String v, String arg) { return "na " + v; } |
| |
| @Test public void testCountedLoop() throws Throwable { |
| MethodHandle MH_start, MH_step; |
| Class<?> S = String.class; |
| MH_start = LOOKUP.findStatic(THIS_CLASS, "start", methodType(S, S)); |
| MH_step = LOOKUP.findStatic(THIS_CLASS, "step", methodType(S, int.class, S, S)); |
| {{ |
| {} /// JAVADOC |
| // String s = "Lambdaman!"; for (int i = 0; i < 13; ++i) { s = "na " + s; } return s; |
| // => a variation on a well known theme |
| MethodHandle fit13 = MethodHandles.constant(int.class, 13); |
| MethodHandle loop = MethodHandles.countedLoop(fit13, MH_start, MH_step); |
| assertEquals("na na na na na na na na na na na na na Lambdaman!", loop.invoke("Lambdaman!")); |
| {} |
| }} |
| } |
| |
| static List<String> reverseStep(String e, List<String> r, List<String> l) { |
| r.add(0, e); |
| return r; |
| } |
| static List<String> newArrayList(List<String> l) { return new ArrayList<>(); } |
| |
| @Test public void testIteratedLoop() throws Throwable { |
| MethodHandle MH_newArrayList, MH_reverseStep; |
| Class<?> L = List.class; |
| MH_newArrayList = LOOKUP.findStatic(THIS_CLASS, "newArrayList", methodType(L, L)); |
| MH_reverseStep = LOOKUP.findStatic(THIS_CLASS, "reverseStep", methodType(L, String.class, L, L)); |
| {{ |
| {} /// JAVADOC |
| // reverse a list |
| MethodHandle loop = MethodHandles.iteratedLoop(null, MH_newArrayList, MH_reverseStep); |
| List<String> list = Arrays.asList("a", "b", "c", "d", "e"); |
| List<String> reversedList = Arrays.asList("e", "d", "c", "b", "a"); |
| assertEquals(reversedList, (List<String>) loop.invoke(list)); |
| {} |
| }} |
| } |
| |
| @Test public void testFoldArguments3() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle trace = publicLookup().findVirtual(java.io.PrintStream.class, |
| "println", methodType(void.class, String.class)) |
| .bindTo(System.out); |
| MethodHandle cat = lookup().findVirtual(String.class, |
| "concat", methodType(String.class, String.class)); |
| assertEquals("boojum", (String) cat.invokeExact("boo", "jum")); |
| MethodHandle catTrace = foldArguments(cat, 1, trace); |
| // also prints "jum": |
| assertEquals("boojum", (String) catTrace.invokeExact("boo", "jum")); |
| {} |
| }} |
| } |
| |
| @Test public void testAsCollector2() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| StringWriter swr = new StringWriter(); |
| MethodHandle swWrite = LOOKUP.findVirtual(StringWriter.class, "write", methodType(void.class, char[].class, int.class, int.class)).bindTo(swr); |
| MethodHandle swWrite4 = swWrite.asCollector(0, char[].class, 4); |
| swWrite4.invoke('A', 'B', 'C', 'D', 1, 2); |
| assertEquals("BC", swr.toString()); |
| swWrite4.invoke('P', 'Q', 'R', 'S', 0, 4); |
| assertEquals("BCPQRS", swr.toString()); |
| swWrite4.invoke('W', 'X', 'Y', 'Z', 3, 1); |
| assertEquals("BCPQRSZ", swr.toString()); |
| {} |
| }} |
| } |
| |
| @Test public void testAsSpreader2() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| MethodHandle compare = LOOKUP.findStatic(Objects.class, "compare", methodType(int.class, Object.class, Object.class, Comparator.class)); |
| MethodHandle compare2FromArray = compare.asSpreader(0, Object[].class, 2); |
| Object[] ints = new Object[]{3, 9, 7, 7}; |
| Comparator<Integer> cmp = (a, b) -> a - b; |
| assertTrue((int) compare2FromArray.invoke(Arrays.copyOfRange(ints, 0, 2), cmp) < 0); |
| assertTrue((int) compare2FromArray.invoke(Arrays.copyOfRange(ints, 1, 3), cmp) > 0); |
| assertTrue((int) compare2FromArray.invoke(Arrays.copyOfRange(ints, 2, 4), cmp) == 0); |
| {} |
| }} |
| } |
| |
| /* ---- TEMPLATE ---- |
| @Test public void testFoo() throws Throwable { |
| {{ |
| {} /// JAVADOC |
| {} |
| }} |
| } |
| */ |
| } |