Java example source code file (InheritIOEHandle.java)

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Java - Java tags/keywords

app, bufferedreader, catastrophe, file, inheritioehandle, interruptedexception, ioexception, java_exe, processbuilder, runtimeexception, signal, string

The InheritIOEHandle.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 7147084
 * @run main/othervm InheritIOEHandle
 * @summary inherit IOE handles and MS CreateProcess limitations (kb315939)
 */

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;

public class InheritIOEHandle {
    private static enum APP {
        A, B, C;
    }

    private static File stopC = new File("StopC.txt");
    private static String SIGNAL = "After call child process";
    private static String JAVA_EXE = System.getProperty("java.home")
            + File.separator + "bin"
            + File.separator + "java";

    private static String[] getCommandArray(String processName) {
        String[] cmdArray = {
                JAVA_EXE,
                "-cp",
                System.getProperty("java.class.path"),
                InheritIOEHandle.class.getName(),
                processName
        };
        return cmdArray;
    }

    public static void main(String[] args) throws Exception {
        if (!System.getProperty("os.name").startsWith("Windows")) {
            return;
        }

        APP app = (args.length > 0) ? APP.valueOf(args[0]) : APP.A;
        switch (app) {
            case A:
                performA();
                break;
            case B:
                performB();
                break;
            case C:
                performC();
                break;
        }
    }

    private static void performA() {
        try {
            stopC.delete();

            ProcessBuilder builder = new ProcessBuilder(
                    getCommandArray(APP.B.name()));
            builder.redirectErrorStream(true);

            Process process = builder.start();

            process.getOutputStream().close();
            process.getErrorStream().close();

            boolean isSignalReceived = false;
            try (BufferedReader in = new BufferedReader(new InputStreamReader(
                    process.getInputStream(), "utf-8")))
            {
                String result;
                while ((result = in.readLine()) != null) {
                    if (SIGNAL.equals(result)) {
                        isSignalReceived = true;
                        break;
                    } else {
                        throw new RuntimeException("Catastrophe in process B! Bad output.");
                    }
                }

            }
            if (!isSignalReceived) {
                throw new RuntimeException("Signal from B was not received");
            }

            // If JDK-7147084 is not fixed that point is unreachable.
            System.out.println("Received signal from B, creating file StopC");
            // write signal file
            boolean isFileStopC = stopC.createNewFile();
            if (!isFileStopC) {
                throw new RuntimeException("Signal file StopC.txt was not created. TEST or INFRA bug");
            }

            process.waitFor();

            System.err.println("Read stream finished.");
        } catch (IOException ex) {
            throw new RuntimeException("Catastrophe in process A!", ex);
        } catch (InterruptedException ex) {
            throw new RuntimeException("A was interrupted while waiting for B", ex);
        }
    }

    private static void performB() {
        try {
            ProcessBuilder builder = new ProcessBuilder(
                    getCommandArray(APP.C.name()));

            Process process = builder.start();

            process.getInputStream().close();
            process.getOutputStream().close();
            process.getErrorStream().close();

            System.out.println(SIGNAL);
            process.waitFor();

            // JDK-7147084 subject:
            // Process C inherits the [System.out] handle and
            // handle close in B does not finalize the streaming for A.
            // (handle reference count > 1).
        } catch (IOException ex) {
            throw new RuntimeException("Catastrophe in process B!", ex);
        } catch (InterruptedException ex) {
            throw new RuntimeException("B was interrupted while waiting for C", ex);
        }
    }

    private static void performC() {
        // If JDK-7147084 is not fixed the loop is 5min long.
        for (int i = 0; i < 5 * 60; ++i) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException ex) {
                // that is ok. Longer sleep - better effect.
            }
            // check for success
            if (stopC.exists()) {
                break;
            }
        }
    }
}