Java example source code file (IntersectionTargetTypeTest.java)

This example Java source code file (IntersectionTargetTypeTest.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

castinfo, castkind, expressionkind, intersectiontargettypetest, javasource, list, methodkind, net, network, string, typekind, util

The IntersectionTargetTypeTest.java Java example source code

/*
 * Copyright (c) 2012, 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 8002099
 * @summary Add support for intersection types in cast expression
 */

import com.sun.source.util.JavacTask;
import com.sun.tools.javac.util.ListBuffer;
import java.net.URI;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.tools.Diagnostic;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;

public class IntersectionTargetTypeTest {

    static int checkCount = 0;

    enum BoundKind {
        INTF,
        CLASS;
    }

    enum MethodKind {
        NONE(false),
        ABSTRACT_M(true),
        DEFAULT_M(false),
        ABSTRACT_G(true),
        DEFAULT_G(false);

        boolean isAbstract;

        MethodKind(boolean isAbstract) {
            this.isAbstract = isAbstract;
        }
    }

    enum TypeKind {
        A("interface A { }\n", "A", BoundKind.INTF, MethodKind.NONE),
        B("interface B { default void m() { } }\n", "B", BoundKind.INTF, MethodKind.DEFAULT_M),
        C("interface C { void m(); }\n", "C", BoundKind.INTF, MethodKind.ABSTRACT_M),
        D("interface D extends B { }\n", "D", BoundKind.INTF, MethodKind.DEFAULT_M),
        E("interface E extends C { }\n", "E", BoundKind.INTF, MethodKind.ABSTRACT_M),
        F("interface F extends C { void g(); }\n", "F", BoundKind.INTF, MethodKind.ABSTRACT_G, MethodKind.ABSTRACT_M),
        G("interface G extends B { void g(); }\n", "G", BoundKind.INTF, MethodKind.ABSTRACT_G, MethodKind.DEFAULT_M),
        H("interface H extends A { void g(); }\n", "H", BoundKind.INTF, MethodKind.ABSTRACT_G),
        OBJECT("", "Object", BoundKind.CLASS),
        STRING("", "String", BoundKind.CLASS);

        String declStr;
        String typeStr;
        BoundKind boundKind;
        MethodKind[] methodKinds;

        private TypeKind(String declStr, String typeStr, BoundKind boundKind, MethodKind... methodKinds) {
            this.declStr = declStr;
            this.typeStr = typeStr;
            this.boundKind = boundKind;
            this.methodKinds = methodKinds;
        }

        boolean compatibleSupertype(TypeKind tk) {
            if (tk == this) return true;
            switch (tk) {
                case B:
                    return this != C && this != E && this != F;
                case C:
                    return this != B && this != C && this != D && this != G;
                case D: return compatibleSupertype(B);
                case E:
                case F: return compatibleSupertype(C);
                case G: return compatibleSupertype(B);
                case H: return compatibleSupertype(A);
                default:
                    return true;
            }
        }
    }

    enum CastKind {
        ONE_ARY("(#B0)", 1),
        TWO_ARY("(#B0 & #B1)", 2),
        THREE_ARY("(#B0 & #B1 & #B2)", 3);

        String castTemplate;
        int nbounds;

        CastKind(String castTemplate, int nbounds) {
            this.castTemplate = castTemplate;
            this.nbounds = nbounds;
        }
    }

    enum ExpressionKind {
        LAMBDA("()->{}", true),
        MREF("this::m", true),
        //COND_LAMBDA("(true ? ()->{} : ()->{})", true), re-enable if spec allows this
        //COND_MREF("(true ? this::m : this::m)", true),
        STANDALONE("null", false);

        String exprString;
        boolean isFunctional;

        private ExpressionKind(String exprString, boolean isFunctional) {
            this.exprString = exprString;
            this.isFunctional = isFunctional;
        }
    }

    static class CastInfo {
        CastKind kind;
        TypeKind[] types;

        CastInfo(CastKind kind, TypeKind... types) {
            this.kind = kind;
            this.types = types;
        }

        String getCast() {
            String temp = kind.castTemplate;
            for (int i = 0; i < kind.nbounds ; i++) {
                temp = temp.replace(String.format("#B%d", i), types[i].typeStr);
            }
            return temp;
        }

        boolean wellFormed() {
            //check for duplicate types
            for (int i = 0 ; i < types.length ; i++) {
                for (int j = 0 ; j < types.length ; j++) {
                    if (i != j && types[i] == types[j]) {
                        return false;
                    }
                }
            }
            //check that classes only appear as first bound
            boolean classOk = true;
            for (int i = 0 ; i < types.length ; i++) {
                if (types[i].boundKind == BoundKind.CLASS &&
                        !classOk) {
                    return false;
                }
                classOk = false;
            }
            //check that supertypes are mutually compatible
            for (int i = 0 ; i < types.length ; i++) {
                for (int j = 0 ; j < types.length ; j++) {
                    if (!types[i].compatibleSupertype(types[j]) && i != j) {
                        return false;
                    }
                }
            }
            return true;
        }
    }

    public static void main(String... args) throws Exception {
        //create default shared JavaCompiler - reused across multiple compilations
        JavaCompiler comp = ToolProvider.getSystemJavaCompiler();
        StandardJavaFileManager fm = comp.getStandardFileManager(null, null, null);

        for (CastInfo cInfo : allCastInfo()) {
            for (ExpressionKind ek : ExpressionKind.values()) {
                new IntersectionTargetTypeTest(cInfo, ek).run(comp, fm);
            }
        }
        System.out.println("Total check executed: " + checkCount);
    }

    static List<CastInfo> allCastInfo() {
        ListBuffer<CastInfo> buf = new ListBuffer<>();
        for (CastKind kind : CastKind.values()) {
            for (TypeKind b1 : TypeKind.values()) {
                if (kind.nbounds == 1) {
                    buf.append(new CastInfo(kind, b1));
                    continue;
                } else {
                    for (TypeKind b2 : TypeKind.values()) {
                        if (kind.nbounds == 2) {
                            buf.append(new CastInfo(kind, b1, b2));
                            continue;
                        } else {
                            for (TypeKind b3 : TypeKind.values()) {
                                buf.append(new CastInfo(kind, b1, b2, b3));
                            }
                        }
                    }
                }
            }
        }
        return buf.toList();
    }

    CastInfo cInfo;
    ExpressionKind ek;
    JavaSource source;
    DiagnosticChecker diagChecker;

    IntersectionTargetTypeTest(CastInfo cInfo, ExpressionKind ek) {
        this.cInfo = cInfo;
        this.ek = ek;
        this.source = new JavaSource();
        this.diagChecker = new DiagnosticChecker();
    }

    class JavaSource extends SimpleJavaFileObject {

        String bodyTemplate = "class Test {\n" +
                              "   void m() { }\n" +
                              "   void test() {\n" +
                              "      Object o = #C#E;\n" +
                              "   } }";

        String source = "";

        public JavaSource() {
            super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);
            for (TypeKind tk : TypeKind.values()) {
                source += tk.declStr;
            }
            source += bodyTemplate.replaceAll("#C", cInfo.getCast()).replaceAll("#E", ek.exprString);
        }

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

    void run(JavaCompiler tool, StandardJavaFileManager fm) throws Exception {
        JavacTask ct = (JavacTask)tool.getTask(null, fm, diagChecker,
                null, null, Arrays.asList(source));
        try {
            ct.analyze();
        } catch (Throwable ex) {
            throw new AssertionError("Error thrown when compiling the following code:\n" + source.getCharContent(true));
        }
        check();
    }

    void check() {
        checkCount++;

        boolean errorExpected = !cInfo.wellFormed();

        if (ek.isFunctional) {
            List<MethodKind> mks = new ArrayList<>();
            for (TypeKind tk : cInfo.types) {
                if (tk.boundKind == BoundKind.CLASS) {
                    errorExpected = true;
                    break;
                } else {
                    mks = mergeMethods(mks, Arrays.asList(tk.methodKinds));
                }
            }
            int abstractCount = 0;
            for (MethodKind mk : mks) {
                if (mk.isAbstract) {
                    abstractCount++;
                }
            }
            errorExpected |= abstractCount != 1;
        }

        if (errorExpected != diagChecker.errorFound) {
            throw new Error("invalid diagnostics for source:\n" +
                source.getCharContent(true) +
                "\nFound error: " + diagChecker.errorFound +
                "\nExpected error: " + errorExpected);
        }
    }

    List<MethodKind> mergeMethods(List l1, List l2) {
        List<MethodKind> mergedMethods = new ArrayList<>(l1);
        for (MethodKind mk2 : l2) {
            boolean add = !mergedMethods.contains(mk2);
            switch (mk2) {
                case ABSTRACT_G:
                    add = add && !mergedMethods.contains(MethodKind.DEFAULT_G);
                    break;
                case ABSTRACT_M:
                    add = add && !mergedMethods.contains(MethodKind.DEFAULT_M);
                    break;
                case DEFAULT_G:
                    mergedMethods.remove(MethodKind.ABSTRACT_G);
                case DEFAULT_M:
                    mergedMethods.remove(MethodKind.ABSTRACT_M);
                case NONE:
                    add = false;
                    break;
            }
            if (add) {
                mergedMethods.add(mk2);
            }
        }
        return mergedMethods;
    }

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

        boolean errorFound;

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