Java example source code file (TestSerializedLambdaNameStability.java)

This example Java source code file (TestSerializedLambdaNameStability.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

bytearrayinputstream, bytearrayoutputstream, classloader, classnotfoundexception, exception, fail, method, object, pass, path, reflection, string, testclassloader, testserializedlambdanamestability, throwable

The TestSerializedLambdaNameStability.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 8023668
 * @summary Desugar serializable lambda bodies using more robust naming scheme
 * @library /tools/javac/lib
 * @build ToolBox
 * @run main TestSerializedLambdaNameStability
 */

import java.io.*;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.file.*;

public class TestSerializedLambdaNameStability {

    final ClassLoader writingClassLoader;
    final ClassLoader clonedClassLoader;
    final ClassLoader checkingClassLoader;

    TestSerializedLambdaNameStability()  {
        writingClassLoader = new TestClassLoader("before");
        clonedClassLoader = new TestClassLoader("before");
        checkingClassLoader = new TestClassLoader("after");
    }

    public static void main(String... args) throws Exception {
        new TestSerializedLambdaNameStability().doit("NameOfCapturedArgs", true);
        new TestSerializedLambdaNameStability().doit("TypesOfCapturedArgs", true);
        new TestSerializedLambdaNameStability().doit("OrderOfCapturedArgs", true);
        new TestSerializedLambdaNameStability().doit("VariableAssignmentTarget", false);
        new TestSerializedLambdaNameStability().doit("TargetName", true);
        new TestSerializedLambdaNameStability().doit("TargetType", true);
    }

    public void doit(String name, boolean expectFail) throws Exception {
        String iName = "I" + name;
        String testName = "TEST" + name;
        Class<?> kw = writingClassLoader.loadClass(testName);
        Object instw = getInstance(kw);
        Method mw = getMethod(kw, "write", ObjectOutput.class);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try (ObjectOutput out = new ObjectOutputStream(baos)) {
            mw.invoke(instw, out);
        }
        byte[] ser = baos.toByteArray();

        // Read and check clone
        readCheck(iName, testName, clonedClassLoader, ser);
        System.err.printf("cloned test readCheck %s\n", testName);

        // Read and check other
        if (expectFail) {
            try {
                readCheck(iName, testName, checkingClassLoader, ser);
            } catch (InvocationTargetException ite) {
                Throwable underlying = ite;
                while (underlying != null && !(underlying instanceof IllegalArgumentException)) {
                    underlying = underlying.getCause();
                }
                if (underlying != null) {
                    if (underlying.getMessage().contains("deserialization")) {
                        System.err.printf("PASS: other test %s got expected exception %s\n", testName, underlying);
                        return;
                    }
                }
                System.err.printf("FAIL: other test %s got unexpected exception %s\n", testName, ite);
                throw new Exception("unexpected exception ", ite);
            }
            System.err.printf("FAIL: other test %s expected an exception", testName);
            throw new Exception("expected an exception" + testName);
        } else {
            readCheck(iName, testName, checkingClassLoader, ser);
            System.err.printf("PASS: other test %s readCheck\n", testName);
        }
    }

    void readCheck(String iName, String testName, ClassLoader loader, byte[] ser) throws Exception {
        Class<?> k = loader.loadClass(testName);
        Object inst = getInstance(k);
        Method mrc = getMethod(k, "readCheck", ObjectInput.class);
        ByteArrayInputStream bais = new ByteArrayInputStream(ser);
        try (ObjectInput in = new ObjectInputStream(bais)) {
            mrc.invoke(inst, in);
        }
    }

    Method getMethod(Class<?> k, String name, Class argTypes) throws Exception {
        Method meth = k.getDeclaredMethod(name, argTypes);
        meth.setAccessible(true);
        return meth;
    }

    Object getInstance(Class<?> k) throws Exception {
        Constructor<?> cons = k.getConstructors()[0];
        cons.setAccessible(true);
        return cons.newInstance();
    }

    static class TestClassLoader extends ClassLoader  {
        static final String compiledDir = System.getProperty("user.dir");
        static final String sourceBaseDir = System.getProperty("test.src");

        final String context;

        public TestClassLoader(String context) {
            super();
            this.context = context;
        }

        @Override
        public Class findClass(String name) throws ClassNotFoundException {
            byte[] b;

            try {
                b = loadClassData(name);
            } catch (Throwable th) {
                // th.printStackTrace();
                throw new ClassNotFoundException("Loading error", th);
            }
            return defineClass(name, b, 0, b.length);
        }

        private byte[] loadClassData(String name) throws Exception {
            String srcName;
            if (name.startsWith("TEST"))
                srcName = name;
            else if (name.startsWith("I"))
                srcName = "TEST" + name.substring(1);
            else
                throw new Exception("Did not expect to load " + name);
            Path srcFile = Paths.get(sourceBaseDir, context, srcName + ".java");
            String testSource = new String(Files.readAllBytes(srcFile));
            ToolBox.JavaToolArgs javacSuccessArgs =
                    new ToolBox.JavaToolArgs().setSources(testSource);
            ToolBox.javac(javacSuccessArgs);
            Path cfFile = Paths.get(compiledDir, name + ".class");
            byte[] bytes = Files.readAllBytes(cfFile);
            return bytes;
        }
    }
}