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Java example source code file (Warn4.java)

This example Java source code file (Warn4.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, javasource, modifierkind, net, network, none, override, signature, sourcelevel, string, suppresslevel, trustme, unchecked, util, varargs, warn4, warning

The Warn4.java Java example source code

/*
 * Copyright (c) 2010, 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     6945418 6993978 8006694
 * @summary Project Coin: Simplified Varargs Method Invocation
 *  temporarily workaround combo tests are causing time out in several platforms
 * @author  mcimadamore
 * @library ../../lib
 * @build JavacTestingAbstractThreadedTest
 * @run main/othervm Warn4
 */

// use /othervm to avoid jtreg timeout issues (CODETOOLS-7900047)
// see JDK-8006746

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

public class Warn4
    extends JavacTestingAbstractThreadedTest
    implements Runnable {

    final static Warning[] error = null;
    final static Warning[] none = new Warning[] {};
    final static Warning[] vararg = new Warning[] { Warning.VARARGS };
    final static Warning[] unchecked = new Warning[] { Warning.UNCHECKED };
    final static Warning[] both =
            new Warning[] { Warning.VARARGS, Warning.UNCHECKED };

    enum Warning {
        UNCHECKED("generic.array.creation"),
        VARARGS("varargs.non.reifiable.type");

        String key;

        Warning(String key) {
            this.key = key;
        }

        boolean isSuppressed(TrustMe trustMe, SourceLevel source,
                SuppressLevel suppressLevelClient,
                SuppressLevel suppressLevelDecl,
                ModifierKind modKind) {
            switch(this) {
                case VARARGS:
                    return source == SourceLevel.JDK_6 ||
                            suppressLevelDecl == SuppressLevel.UNCHECKED ||
                            trustMe == TrustMe.TRUST;
                case UNCHECKED:
                    return suppressLevelClient == SuppressLevel.UNCHECKED ||
                        (trustMe == TrustMe.TRUST && modKind !=
                            ModifierKind.NONE && source == SourceLevel.JDK_7);
            }

            SuppressLevel supLev = this == VARARGS ?
                suppressLevelDecl :
                suppressLevelClient;
            return supLev == SuppressLevel.UNCHECKED ||
                    (trustMe == TrustMe.TRUST && modKind != ModifierKind.NONE);
        }
    }

    enum SourceLevel {
        JDK_6("6"),
        JDK_7("7");

        String sourceKey;

        SourceLevel(String sourceKey) {
            this.sourceKey = sourceKey;
        }
    }

    enum TrustMe {
        DONT_TRUST(""),
        TRUST("@java.lang.SafeVarargs");

        String anno;

        TrustMe(String anno) {
            this.anno = anno;
        }
    }

    enum ModifierKind {
        NONE(" "),
        FINAL("final "),
        STATIC("static ");

        String mod;

        ModifierKind(String mod) {
            this.mod = mod;
        }
    }

    enum SuppressLevel {
        NONE(""),
        UNCHECKED("unchecked");

        String lint;

        SuppressLevel(String lint) {
            this.lint = lint;
        }

        String getSuppressAnno() {
            return "@SuppressWarnings(\"" + lint + "\")";
        }
    }

    enum Signature {
        UNBOUND("void #name(List<?>#arity arg) { #body }",
            new Warning[][] {none, none, none, none, error}),
        INVARIANT_TVAR("<Z> void #name(List#arity arg) { #body }",
            new Warning[][] {both, both, error, both, error}),
        TVAR("<Z> void #name(Z#arity arg) { #body }",
            new Warning[][] {both, both, both, both, vararg}),
        INVARIANT("void #name(List<String>#arity arg) { #body }",
            new Warning[][] {error, error, error, both, error}),
        UNPARAMETERIZED("void #name(String#arity arg) { #body }",
            new Warning[][] {error, error, error, error, none});

        String template;
        Warning[][] warnings;

        Signature(String template, Warning[][] warnings) {
            this.template = template;
            this.warnings = warnings;
        }

        boolean isApplicableTo(Signature other) {
            return warnings[other.ordinal()] != null;
        }

        boolean giveUnchecked(Signature other) {
            return warnings[other.ordinal()] == unchecked ||
                    warnings[other.ordinal()] == both;
        }

        boolean giveVarargs(Signature other) {
            return warnings[other.ordinal()] == vararg ||
                    warnings[other.ordinal()] == both;
        }
    }

    public static void main(String... args) throws Exception {
        for (SourceLevel sourceLevel : SourceLevel.values()) {
            for (TrustMe trustMe : TrustMe.values()) {
                for (SuppressLevel suppressLevelClient : SuppressLevel.values()) {
                    for (SuppressLevel suppressLevelDecl : SuppressLevel.values()) {
                        for (ModifierKind modKind : ModifierKind.values()) {
                            for (Signature vararg_meth : Signature.values()) {
                                for (Signature client_meth : Signature.values()) {
                                    if (vararg_meth.isApplicableTo(client_meth)) {
                                        pool.execute(new Warn4(sourceLevel,
                                                trustMe,
                                                suppressLevelClient,
                                                suppressLevelDecl,
                                                modKind,
                                                vararg_meth,
                                                client_meth));
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }

        checkAfterExec();
    }

    SourceLevel sourceLevel;
    TrustMe trustMe;
    SuppressLevel suppressLevelClient;
    SuppressLevel suppressLevelDecl;
    ModifierKind modKind;
    Signature vararg_meth;
    Signature client_meth;
    DiagnosticChecker diagChecker;

    public Warn4(SourceLevel sourceLevel, TrustMe trustMe,
            SuppressLevel suppressLevelClient, SuppressLevel suppressLevelDecl,
            ModifierKind modKind, Signature vararg_meth, Signature client_meth) {
        this.sourceLevel = sourceLevel;
        this.trustMe = trustMe;
        this.suppressLevelClient = suppressLevelClient;
        this.suppressLevelDecl = suppressLevelDecl;
        this.modKind = modKind;
        this.vararg_meth = vararg_meth;
        this.client_meth = client_meth;
        this.diagChecker = new DiagnosticChecker();
    }

    @Override
    public void run() {
        int id = checkCount.incrementAndGet();
        final JavaCompiler tool = ToolProvider.getSystemJavaCompiler();
        JavaSource source = new JavaSource(id);
        JavacTask ct = (JavacTask)tool.getTask(null, fm.get(), diagChecker,
                Arrays.asList("-Xlint:unchecked", "-source", sourceLevel.sourceKey),
                null, Arrays.asList(source));
        ct.call(); //to get mandatory notes
        check(source, new boolean[] {vararg_meth.giveUnchecked(client_meth),
                               vararg_meth.giveVarargs(client_meth)});
    }

    void check(JavaSource source, boolean[] warnArr) {
        boolean badOutput = false;
        for (Warning wkind : Warning.values()) {
            boolean isSuppressed = wkind.isSuppressed(trustMe, sourceLevel,
                    suppressLevelClient, suppressLevelDecl, modKind);
            badOutput |= (warnArr[wkind.ordinal()] && !isSuppressed) !=
                    diagChecker.warnings.contains(wkind);
        }
        if (badOutput) {
            throw new Error("invalid diagnostics for source:\n" +
                    source.getCharContent(true) +
                    "\nExpected unchecked warning: " + warnArr[0] +
                    "\nExpected unsafe vararg warning: " + warnArr[1] +
                    "\nWarnings: " + diagChecker.warnings +
                    "\nSource level: " + sourceLevel);
        }
    }

    class JavaSource extends SimpleJavaFileObject {

        String source;

        public JavaSource(int id) {
            super(URI.create(String.format("myfo:/Test%d.java", id)),
                    JavaFileObject.Kind.SOURCE);
            String meth1 = vararg_meth.template.replace("#arity", "...");
            meth1 = meth1.replace("#name", "m");
            meth1 = meth1.replace("#body", "");
            meth1 = trustMe.anno + "\n" + suppressLevelDecl.getSuppressAnno() +
                    modKind.mod + meth1;
            String meth2 = client_meth.template.replace("#arity", "");
            meth2 = meth2.replace("#name", "test");
            meth2 = meth2.replace("#body", "m(arg);");
            meth2 = suppressLevelClient.getSuppressAnno() + meth2;
            source = String.format("import java.util.List;\n" +
                     "class Test%s {\n %s \n %s \n } \n", id, meth1, meth2);
        }

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

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

        Set<Warning> warnings = new HashSet<>();

        public void report(Diagnostic<? extends JavaFileObject> diagnostic) {
            if (diagnostic.getKind() == Diagnostic.Kind.MANDATORY_WARNING ||
                    diagnostic.getKind() == Diagnostic.Kind.WARNING) {
                if (diagnostic.getCode().contains(Warning.VARARGS.key)) {
                    warnings.add(Warning.VARARGS);
                } else if(diagnostic.getCode().contains(Warning.UNCHECKED.key)) {
                    warnings.add(Warning.UNCHECKED);
                }
            }
        }
    }

}

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