Java example source code file (BadLambdaExpr.java)

This example Java source code file (BadLambdaExpr.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

arrowkind, badlambdaexpr, diagnosticchecker, error, exception, exprkind, javasource, net, network, none, override, parameterkind, parameterlistkind, standardjavafilemanager, string, util

The BadLambdaExpr.java Java example source code

/*
 * Copyright (c) 2012, 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
 *  compile crashes on partial lambda expressions
 */

import com.sun.source.util.JavacTask;
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;


public class BadLambdaExpr {

    static int checkCount = 0;

    enum ParameterListKind {
        ZERO_ARY("()"),
        UNARY("(#P)"),
        TWO_ARY("(#P, #P)"),
        THREE_ARY("(#P, #P, #P)");

        String parametersTemplateStr;

        ParameterListKind(String parametersTemplateStr) {
            this.parametersTemplateStr = parametersTemplateStr;
        }

        String getParameterString(ParameterKind pk) {
            return parametersTemplateStr.replaceAll("#P", pk.parameterStr);
        }
    }

    enum ParameterKind {
        IMPLICIT("a"),
        EXPLIICT("A a");

        String parameterStr;

        ParameterKind(String parameterStr) {
            this.parameterStr = parameterStr;
        }
    }

    enum ArrowKind {
        NONE(""),
        SEMI("-"),
        FULL("->");

        String arrowStr;

        ArrowKind(String arrowStr) {
            this.arrowStr = arrowStr;
        }
    }

    enum ExprKind {
        NONE("#P#A"),
        METHOD_CALL("m(#P#A)"),
        CONSTR_CALL("new Foo(#P#A)");

        String expressionTemplate;

        ExprKind(String expressionTemplate) {
            this.expressionTemplate = expressionTemplate;
        }

        String expressionString(ParameterListKind plk, ParameterKind pk,
                ArrowKind ak) {
            return expressionTemplate.replaceAll("#P", plk.getParameterString(pk))
                    .replaceAll("#A", ak.arrowStr);
        }
    }

    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 (ParameterListKind plk : ParameterListKind.values()) {
            for (ParameterKind pk : ParameterKind.values()) {
                for (ArrowKind ak : ArrowKind.values()) {
                    for (ExprKind ek : ExprKind.values()) {
                        new BadLambdaExpr(plk, pk, ak, ek).run(comp, fm);
                    }
                }
            }
        }
        System.out.println("Total check executed: " + checkCount);
    }

    ParameterListKind plk;
    ParameterKind pk;
    ArrowKind ak;
    ExprKind ek;
    JavaSource source;
    DiagnosticChecker diagChecker;

    BadLambdaExpr(ParameterListKind plk, ParameterKind pk, ArrowKind ak, ExprKind ek) {
        this.plk = plk;
        this.pk = pk;
        this.ak = ak;
        this.ek = ek;
        this.source = new JavaSource();
        this.diagChecker = new DiagnosticChecker();
    }

    class JavaSource extends SimpleJavaFileObject {

        String template = "class Test {\n" +
                          "   SAM s = #E;\n" +
                          "}";

        String source;

        public JavaSource() {
            super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);
            source = template.replaceAll("#E", ek.expressionString(plk, pk, ak));
        }

        @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.parse();
        } catch (Throwable ex) {
            throw new AssertionError("Error thron when parsing the following source:\n" + source.getCharContent(true));
        }
        check();
    }

    void check() {
        boolean errorExpected =
                ak != ArrowKind.NONE ||
                plk != ParameterListKind.UNARY ||
                pk != ParameterKind.IMPLICIT;
        if (errorExpected != diagChecker.errorFound) {
            throw new Error("bad diag for source:\n" +
                source.getCharContent(true));
        }
        checkCount++;
    }

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

        boolean errorFound;

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