Java example source code file (TestSelfRef.java)

This example Java source code file (TestSelfRef.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

diagnosticchecker, enclosingkind, innerkind, javasource, net, network, none, object, refkind, sitekind, standardjavafilemanager, string, testselfref, util

The TestSelfRef.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 8003280
 * @summary Add lambda tests
 *  Check that self/forward references from lambda expressions behave
 *          consistently w.r.t. local inner classes
 */

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

public class TestSelfRef {

    static int checkCount = 0;

    enum RefKind {
        SELF_LAMBDA("SAM s = x->{ System.out.println(s); };", true, false),
        FORWARD_LAMBDA("SAM s = x->{ System.out.println(f); };\nObject f = null;", false, true),
        SELF_ANON("Object s = new Object() { void test() { System.out.println(s); } };", true, false),
        FORWARD_ANON("Object s = new Object() { void test() { System.out.println(f); } }; Object f = null;", false, true);

        String refStr;
        boolean selfRef;
        boolean forwardRef;

        private RefKind(String refStr, boolean selfRef, boolean forwardRef) {
            this.refStr = refStr;
            this.selfRef = selfRef;
            this.forwardRef = forwardRef;
        }
    }

    enum EnclosingKind {
        TOPLEVEL("class C { #S }"),
        MEMBER_INNER("class Outer { class C { #S } }"),
        NESTED_INNER("class Outer { static class C { #S } }");

        String enclStr;

        private EnclosingKind(String enclStr) {
            this.enclStr = enclStr;
        }
    }

    enum InnerKind {
        NONE("#R"),
        LOCAL_NONE("class Local { #R }"),
        LOCAL_MTH("class Local { void test() { #R } }"),
        ANON_NONE("new Object() { #R };"),
        ANON_MTH("new Object() { void test() { #R } };");

        String innerStr;

        private InnerKind(String innerStr) {
            this.innerStr = innerStr;
        }

        boolean inMethodContext(SiteKind sk) {
            switch (this) {
                case LOCAL_MTH:
                case ANON_MTH: return true;
                case NONE: return sk != SiteKind.NONE;
                default:
                    return false;
            }
        }
    }

    enum SiteKind {
        NONE("#I"),
        STATIC_INIT("static { #I }"),
        INSTANCE_INIT("{ #I }"),
        CONSTRUCTOR("C() { #I }"),
        METHOD("void test() { #I }");

        String siteStr;

        private SiteKind(String siteStr) {
            this.siteStr = siteStr;
        }
    }

    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 (EnclosingKind ek : EnclosingKind.values()) {
            for (SiteKind sk : SiteKind.values()) {
                if (sk == SiteKind.STATIC_INIT && ek == EnclosingKind.MEMBER_INNER)
                    continue;
                for (InnerKind ik : InnerKind.values()) {
                    if (ik != InnerKind.NONE && sk == SiteKind.NONE)
                        break;
                    for (RefKind rk : RefKind.values()) {
                        new TestSelfRef(ek, sk, ik, rk).run(comp, fm);
                    }
                }
            }
        }
        System.out.println("Total check executed: " + checkCount);
    }

    EnclosingKind ek;
    SiteKind sk;
    InnerKind ik;
    RefKind rk;
    JavaSource source;
    DiagnosticChecker diagChecker;

    TestSelfRef(EnclosingKind ek, SiteKind sk, InnerKind ik, RefKind rk) {
        this.ek = ek;
        this.sk = sk;
        this.ik = ik;
        this.rk = rk;
        this.source = new JavaSource();
        this.diagChecker = new DiagnosticChecker();
    }

    class JavaSource extends SimpleJavaFileObject {

        String bodyTemplate = "interface SAM { void test(Object o); }\n#B";
        String source;

        public JavaSource() {
            super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);
            source = bodyTemplate.replace("#B",
                    ek.enclStr.replace("#S", sk.siteStr.replace("#I", ik.innerStr.replace("#R", rk.refStr))));
        }

        @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 thron when compiling the following code:\n" + source.getCharContent(true));
        }
        check();
    }

    boolean isErrorExpected() {
        //illegal forward ref
        boolean result = ik.inMethodContext(sk) && (rk.selfRef || rk.forwardRef);
        result |= (rk == RefKind.SELF_LAMBDA || rk == RefKind.FORWARD_LAMBDA);
        return result;
    }

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

    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;
            }
        }
    }
}