Ziele Untersuchung
mit Columbo Integrität von
Datenbanken Interaktion und
Portierbarkeit Ergonomie der
Schnittstellen

Angebot Produkte Projekt Beratung

Mittel Analytik Modellierung Sprachen Algebra Logik Hardware Denken Kreativität

Zusammenhänge Gesellschaft Wirtschaft Branche Firma


products/Sources/formale Sprachen/Java/Openjdk/src/hotspot/cpu/s390/ (Sun/Oracle ^©) Datei vom 13.11.2022 mit Größe 25 kB

Impressum Truncate.java Sprache: JAVA

/*
* Copyright (c) 2000, 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 6191269 6709457 8000330
* @summary Test truncate method of FileChannel
* @key randomness
*/

import java.io.*;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.nio.file.Files;
import static java.nio.file.StandardOpenOption.*;
import static java.nio.charset.StandardCharsets.*;
import java.util.Random;

/**
* Testing FileChannel's truncate method.
*/

public class Truncate {
    private static final Random generator = new Random();

    public static void main(String[] args) throws Exception {
        File blah = File.createTempFile("blah", null);
        blah.deleteOnExit();
        try {
            basicTest(blah);
            appendTest(blah);
            exceptionTests(blah);
        } finally {
            blah.delete();
        }
    }

    /**
     * Basic test of asserts in truncate's specification.
     */
    static void basicTest(File blah) throws Exception {
        for(int i=0; i<100; i++) {
            long testSize = generator.nextInt(1000) + 10;
            initTestFile(blah, testSize);

            try (FileChannel fc = (i < 50) ?
                 new RandomAccessFile(blah, "rw").getChannel() :
                 FileChannel.open(blah.toPath(), READ, WRITE))
                {
                    if (fc.size() != testSize)
                        throw new RuntimeException("Size failed");

                    long position = generator.nextInt((int)testSize*2);
                    fc.position(position);

                    long newSize = generator.nextInt((int)testSize*2);
                    fc.truncate(newSize);

                    // check new size
                    if (newSize > testSize) {
                        if (fc.size() != testSize)
                            throw new RuntimeException("Attempt to expand file changed size");
                    } else {
                        if (fc.size() != newSize)
                            throw new RuntimeException("Unexpected size after truncate");
                    }

                    // check new position
                    if (position > newSize) {
                        if (fc.position() != newSize)
                            throw new RuntimeException("Position greater than size");
                    } else {
                        if (fc.position() != position)
                            throw new RuntimeException("Truncate changed position");
                    };
                }
        }
    }

    /**
     * Test behavior of truncate method when file is opened for append
     */
    static void appendTest(File blah) throws Exception {
        for (int i=0; i<10; i++) {
            long testSize = generator.nextInt(1000) + 10;
            initTestFile(blah, testSize);
            try (FileChannel fc = (i < 5) ?
                 new FileOutputStream(blah, true).getChannel() :
                 FileChannel.open(blah.toPath(), APPEND))
                {
                    // truncate file
                    long newSize = generator.nextInt((int)testSize);
                    fc.truncate(newSize);
                    if (fc.size() != newSize)
                        throw new RuntimeException("Truncate failed");

                    // write one byte
                    ByteBuffer buf = ByteBuffer.allocate(1);
                    buf.put((byte)'x');
                    buf.flip();
                    fc.write(buf);
                    if (fc.size() != (newSize+1))
                        throw new RuntimeException("Unexpected size");
                }
        }
    }

    /**
     * Test exceptions specified by truncate method
     */
    static void exceptionTests(File blah) throws Exception {
        // check exceptions when channel opened for read access
        try (FileChannel fc = FileChannel.open(blah.toPath(), READ)) {
            long size = fc.size();

            // open channel
            checkException(fc, 0L, NonWritableChannelException.class);

            checkException(fc, -1L, NonWritableChannelException.class,
                           IllegalArgumentException.class);

            checkException(fc, size+1L, NonWritableChannelException.class);

            // closed channel
            fc.close();

            checkException(fc, 0L, ClosedChannelException.class);

            checkException(fc, -1L, ClosedChannelException.class,
                           IllegalArgumentException.class);

            checkException(fc, size+1L, ClosedChannelException.class);
        }

        // check exceptions when channel opened for write access
        try (FileChannel fc = FileChannel.open(blah.toPath(), WRITE)) {
            long size = fc.size();

            // open channel
            checkException(fc, -1L, IllegalArgumentException.class);

            // closed channel
            fc.close();

            checkException(fc, 0L, ClosedChannelException.class);

            checkException(fc, -1L, ClosedChannelException.class,
                           IllegalArgumentException.class);

            checkException(fc, size+1L, ClosedChannelException.class);
        }
    }

    /**
     * Checks that FileChannel truncate throws one of the expected exceptions
     * when invoked with the given size.
     */
    private static void checkException(FileChannel fc, long size, Class<?>... expected)
        throws IOException
    {
        Exception exc = null;
        try {
            fc.truncate(size);
        } catch (Exception actual) {
            exc = actual;
        }
        if (exc != null) {
            for (Class<?> clazz: expected) {
                if (clazz.isInstance(exc)) {
                    return;
                }
            }
        }
        System.err.println("Expected one of");
        for (Class<?> clazz: expected) {
            System.err.println(clazz);
        }
        if (exc == null) {
            throw new RuntimeException("No expection thrown");
        } else {
            throw new RuntimeException("Unexpected exception thrown", exc);
        }
    }

    /**
     * Creates file blah of specified size in bytes.
     */
    private static void initTestFile(File blah, long size) throws Exception {
        try (BufferedWriter writer = Files.newBufferedWriter(blah.toPath(), ISO_8859_1)) {
            for(int i=0; i<size; i++) {
                writer.write("e");
            }
        }
    }
}

quality87%

¤ Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.0.33Bemerkung: (vorverarbeitet) ¤

*Bot Zugriff

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.