Java example source code file (TestMetafactoryBridges.java)

This example Java source code file (TestMetafactoryBridges.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

assertionerror, classkind, classpathkind, file, javafileobject, javasource, jcdiagnostic, list, net, network, override, preferpolicy, printwriter, sourcepathkind, string, util

The TestMetafactoryBridges.java Java example source code

/*
 * Copyright (c) 2013, 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
 * @bug 8013789
 * @summary Compiler should emit bridges in interfaces
 */

import com.sun.source.util.JavacTask;
import com.sun.tools.javac.api.ClientCodeWrapper.DiagnosticSourceUnwrapper;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.util.JCDiagnostic;

import java.io.File;
import java.io.PrintWriter;
import java.net.URI;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.EnumSet;
import java.util.List;
import java.util.Set;

import javax.tools.Diagnostic;
import javax.tools.Diagnostic.Kind;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;
import javax.tools.ToolProvider;

public class TestMetafactoryBridges {

    static int checkCount = 0;

    enum ClasspathKind {
        NONE(),
        B7(7, ClassKind.B),
        A7(7, ClassKind.A),
        B8(8, ClassKind.B),
        A8(8, ClassKind.A);

        int version;
        ClassKind ck;

        ClasspathKind() {
            this(-1, null);
        }

        ClasspathKind(int version, ClassKind ck) {
            this.version = version;
            this.ck = ck;
        }
    }

    enum PreferPolicy {
        SOURCE("-Xprefer:source"),
        NEWER("-Xprefer:newer");

        String preferOpt;

        PreferPolicy(String preferOpt) {
            this.preferOpt = preferOpt;
        }
    }

    enum SourcepathKind {
        NONE,
        A(ClassKind.A),
        B(ClassKind.B),
        C(ClassKind.C),
        AB(ClassKind.A, ClassKind.B),
        BC(ClassKind.B, ClassKind.C),
        AC(ClassKind.A, ClassKind.C),
        ABC(ClassKind.A, ClassKind.B, ClassKind.C);

        List<ClassKind> sources;

        SourcepathKind(ClassKind... sources) {
            this.sources = Arrays.asList(sources);
        }
    }

    enum SourceSet {
        ALL() {
            @Override
            List<List permutations() {
                return Arrays.asList(
                    Arrays.asList(ClassKind.A, ClassKind.B, ClassKind.C),
                    Arrays.asList(ClassKind.A, ClassKind.B, ClassKind.C),
                    Arrays.asList(ClassKind.B, ClassKind.A, ClassKind.C),
                    Arrays.asList(ClassKind.B, ClassKind.C, ClassKind.A),
                    Arrays.asList(ClassKind.C, ClassKind.A, ClassKind.B),
                    Arrays.asList(ClassKind.C, ClassKind.B, ClassKind.A)
                );
            }
        },
        AC() {
            @Override
            List<List permutations() {
                return Arrays.asList(
                    Arrays.asList(ClassKind.A, ClassKind.C),
                    Arrays.asList(ClassKind.C, ClassKind.A)
                );
            }
        },
        C() {
            @Override
            List<List permutations() {
                return Arrays.asList(Arrays.asList(ClassKind.C));
            }
        };

        abstract List<List permutations();
    }

    enum ClassKind {
        A("A", "interface A { Object m(); }"),
        B("B", "interface B extends A { Integer m(); }", A),
        C("C", "class C { B b = ()->42; }", A, B);

        String name;
        String source;
        ClassKind[] deps;

        ClassKind(String name, String source, ClassKind... deps) {
            this.name = name;
            this.source = source;
            this.deps = deps;
        }
    }

    public static void main(String... args) throws Exception {
        String SCRATCH_DIR = System.getProperty("user.dir");
        //create default shared JavaCompiler - reused across multiple compilations
        JavaCompiler comp = ToolProvider.getSystemJavaCompiler();

        int n = 0;
        for (SourceSet ss : SourceSet.values()) {
            for (List<ClassKind> sources : ss.permutations()) {
                for (SourcepathKind spKind : SourcepathKind.values()) {
                    for (ClasspathKind cpKind : ClasspathKind.values()) {
                        for (PreferPolicy pp : PreferPolicy.values()) {
                            Set<ClassKind> deps = EnumSet.noneOf(ClassKind.class);
                            if (cpKind.ck != null) {
                                deps.add(cpKind.ck);
                            }
                            deps.addAll(sources);
                            if (deps.size() < 3) continue;
                            File testDir = new File(SCRATCH_DIR, "test" + n);
                            testDir.mkdir();
                            try (PrintWriter debugWriter = new PrintWriter(new File(testDir, "debug.txt"))) {
                                new TestMetafactoryBridges(testDir, sources, spKind, cpKind, pp, debugWriter).run(comp);
                                n++;
                            }
                        }
                    }
                }
            }
        }
        System.out.println("Total check executed: " + checkCount);
    }

    File testDir;
    List<ClassKind> sources;
    SourcepathKind spKind;
    ClasspathKind cpKind;
    PreferPolicy pp;
    PrintWriter debugWriter;
    DiagnosticChecker diagChecker;

    TestMetafactoryBridges(File testDir, List<ClassKind>sources, SourcepathKind spKind,
            ClasspathKind cpKind, PreferPolicy pp, PrintWriter debugWriter) {
        this.testDir = testDir;
        this.sources = sources;
        this.spKind = spKind;
        this.cpKind = cpKind;
        this.pp = pp;
        this.debugWriter = debugWriter;
        this.diagChecker = new DiagnosticChecker();
    }

    class JavaSource extends SimpleJavaFileObject {

        final String source;

        public JavaSource(ClassKind ck) {
            super(URI.create(String.format("myfo:/%s.java", ck.name)), JavaFileObject.Kind.SOURCE);
            this.source = ck.source;
        }

        @Override
        public CharSequence getCharContent(boolean ignoreEncodingErrors) {
            return source;
        }
    }

    void run(JavaCompiler tool) throws Exception {
        File classesDir = new File(testDir, "classes");
        File outDir = new File(testDir, "out");
        File srcDir = new File(testDir, "src");
        classesDir.mkdir();
        outDir.mkdir();
        srcDir.mkdir();

        debugWriter.append(testDir.getName() + "\n");
        debugWriter.append("sources = " + sources + "\n");
        debugWriter.append("spKind = " + spKind  + "\n");
        debugWriter.append("cpKind = " + cpKind + "\n");
        debugWriter.append("preferPolicy = " + pp.preferOpt + "\n");

        //step 1 - prepare sources (older!!)
        debugWriter.append("Preparing sources\n");
        for (ClassKind ck : spKind.sources) {
            //skip sources explicitly provided on command line
            if (!sources.contains(ck)) {
                debugWriter.append("Copy " + ck.name + ".java to" + srcDir.getAbsolutePath() + "\n");
                File dest = new File(srcDir, ck.name + ".java");
                PrintWriter pw = new PrintWriter(dest);
                pw.append(ck.source);
                pw.close();
            }
        }

        //step 2 - prepare classes
        debugWriter.append("Preparing classes\n");
        if (cpKind != ClasspathKind.NONE) {
            List<JavaSource> sources = new ArrayList<>();
            ClassKind toRemove = null;
            sources.add(new JavaSource(cpKind.ck));
            if (cpKind.ck.deps.length != 0) {
                //at most only one dependency
                toRemove = cpKind.ck.deps[0];
                sources.add(new JavaSource(toRemove));
            }
            JavacTask ct = (JavacTask)tool.getTask(debugWriter, null, null,
                    Arrays.asList("-d", classesDir.getAbsolutePath(), "-source", String.valueOf(cpKind.version)), null, sources);
            try {
                ct.generate();
                if (toRemove != null) {
                    debugWriter.append("Remove " + toRemove.name + ".class from" + classesDir.getAbsolutePath() + "\n");
                    File fileToRemove = new File(classesDir, toRemove.name + ".class");
                    fileToRemove.delete();
                }
            } catch (Throwable ex) {
                throw new AssertionError("Error thrown when generating side-classes");
            }
        }

        //step 3 - compile
        debugWriter.append("Compiling test\n");
        List<JavaSource> sourcefiles = new ArrayList<>();
        for (ClassKind ck : sources) {
            sourcefiles.add(new JavaSource(ck));
        }
        JavacTask ct = (JavacTask)tool.getTask(debugWriter, null, diagChecker,
                    Arrays.asList("-XDdumpLambdaToMethodStats", "-d", outDir.getAbsolutePath(),
                                  "-sourcepath", srcDir.getAbsolutePath(),
                                  "-classpath", classesDir.getAbsolutePath(),
                                  pp.preferOpt), null, sourcefiles);
        try {
            ct.generate();
        } catch (Throwable ex) {
            throw new AssertionError("Error thrown when compiling test case");
        }
        check();
    }

    void check() {
        checkCount++;
        if (diagChecker.errorFound) {
            throw new AssertionError("Unexpected compilation failure");
        }

        boolean altMetafactory =
                cpKind == ClasspathKind.B7 &&
                !sources.contains(ClassKind.B) &&
                (pp == PreferPolicy.NEWER || !spKind.sources.contains(ClassKind.B));

        if (altMetafactory != diagChecker.altMetafactory) {
            throw new AssertionError("Bad metafactory detected - expected altMetafactory: " + altMetafactory +
                    "\ntest: " + testDir);
        }
    }

    static class DiagnosticChecker implements javax.tools.DiagnosticListener<JavaFileObject> {

        boolean altMetafactory = false;
        boolean errorFound = false;

        public void report(Diagnostic<? extends JavaFileObject> diagnostic) {
            if (diagnostic.getKind() == Diagnostic.Kind.ERROR) {
                errorFound = true;
            } else if (statProcessor.matches(diagnostic)) {
                statProcessor.process(diagnostic);
            }
        }

        abstract class DiagnosticProcessor {

            List<String> codes;
            Diagnostic.Kind kind;

            public DiagnosticProcessor(Kind kind, String... codes) {
                this.codes = Arrays.asList(codes);
                this.kind = kind;
            }

            abstract void process(Diagnostic<? extends JavaFileObject> diagnostic);

            boolean matches(Diagnostic<? extends JavaFileObject> diagnostic) {
                return (codes.isEmpty() || codes.contains(diagnostic.getCode())) &&
                        diagnostic.getKind() == kind;
            }

            JCDiagnostic asJCDiagnostic(Diagnostic<? extends JavaFileObject> diagnostic) {
                if (diagnostic instanceof JCDiagnostic) {
                    return (JCDiagnostic)diagnostic;
                } else if (diagnostic instanceof DiagnosticSourceUnwrapper) {
                    return ((DiagnosticSourceUnwrapper)diagnostic).d;
                } else {
                    throw new AssertionError("Cannot convert diagnostic to JCDiagnostic: " + diagnostic.getClass().getName());
                }
            }
        }

        DiagnosticProcessor statProcessor = new DiagnosticProcessor(Kind.NOTE,
                "compiler.note.lambda.stat",
                "compiler.note.mref.stat",
                "compiler.note.mref.stat.1") {
            @Override
            void process(Diagnostic<? extends JavaFileObject> diagnostic) {
                JCDiagnostic diag = asJCDiagnostic(diagnostic);
                if ((Boolean)diag.getArgs()[0]) {
                    altMetafactory = true;
                }
            }
        };
    }
}