Java example source code file (MaxPathLength.java)

This example Java source code file (MaxPathLength.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

directorynotemptyexception, file, fileoutputstream, max_length, max_length\/2, maxpathlength, path, renamed, runtimeexception, string, windows

The MaxPathLength.java Java example source code

/*
 * Copyright (c) 2002, 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 4759207 4403166 4165006 4403166 6182812 6274272 7160013
   @summary Test to see if win32 path length can be greater than 260
 */

import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.DirectoryNotEmptyException;

public class MaxPathLength {
    private static String sep = File.separator;
    private static String pathComponent = sep +
        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
    private static String fileName =
                 "areallylongfilenamethatsforsur";
    private static boolean isWindows = false;

    private final static int MAX_LENGTH = 256;

    private static int counter = 0;

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

        for (int i = 4; i < 7; i++) {
            String name = fileName;
            while (name.length() < MAX_LENGTH) {
                testLongPath (i, name, false);
                testLongPath (i, name, true);
                name = getNextName(name);
            }
        }

        // test long paths on windows
        // And these long pathes cannot be handled on Solaris and Mac platforms
        if (isWindows) {
            String name = fileName;
            while (name.length() < MAX_LENGTH) {
                testLongPath (20, name, false);
                testLongPath (20, name, true);
                name = getNextName(name);
            }
        }
    }

    private static String getNextName(String fName) {
        return (fName.length() < MAX_LENGTH/2) ? fName + fName
                                               : fName + "A";
    }

    static void testLongPath(int max, String fn,
                             boolean tryAbsolute) throws Exception {
        String[] created = new String[max];
        String pathString = ".";
        for (int i = 0; i < max -1; i++) {
            pathString = pathString + pathComponent + (counter++);
            created[max - 1 -i] = pathString;
        }

        File dirFile = new File(pathString);
        File f = new File(pathString + sep + fn);

        String tPath = f.getPath();
        if (tryAbsolute) {
            tPath = f.getCanonicalPath();
        }
        created[0] = tPath;

        //for getCanonicalPath testing on win32
        File fu = new File(pathString + sep + fn.toUpperCase());

        if (dirFile.exists()) {
            System.err.println("Warning: Test directory structure exists already!");
            return;
        }

        try {
            Files.createDirectories(dirFile.toPath());

            if (tryAbsolute)
                dirFile = new File(dirFile.getCanonicalPath());
            if (!dirFile.isDirectory())
                throw new RuntimeException ("File.isDirectory() failed");
            f = new File(tPath);
            if (!f.createNewFile()) {
                throw new RuntimeException ("File.createNewFile() failed");
            }

            if (!f.exists())
                throw new RuntimeException ("File.exists() failed");
            if (!f.isFile())
                throw new RuntimeException ("File.isFile() failed");
            if (!f.canRead())
                throw new RuntimeException ("File.canRead() failed");
            if (!f.canWrite())
                throw new RuntimeException ("File.canWrite() failed");

            if (!f.delete())
                throw new RuntimeException ("File.delete() failed");

            FileOutputStream fos = new FileOutputStream(f);
            fos.write(1);
            fos.close();

            if (f.length() != 1)
                throw new RuntimeException ("File.length() failed");
            long time = System.currentTimeMillis();
            if (!f.setLastModified(time))
                throw new RuntimeException ("File.setLastModified() failed");
            if (f.lastModified() == 0) {
                throw new RuntimeException ("File.lastModified() failed");
            }
            String[] list = dirFile.list();
            if (list == null || !fn.equals(list[0])) {
                throw new RuntimeException ("File.list() failed");
            }

            File[] flist = dirFile.listFiles();
            if (flist == null || !fn.equals(flist[0].getName()))
                throw new RuntimeException ("File.listFiles() failed");

            if (isWindows &&
                !fu.getCanonicalPath().equals(f.getCanonicalPath()))
                throw new RuntimeException ("getCanonicalPath() failed");

            char[] cc = tPath.toCharArray();
            cc[cc.length-1] = 'B';
            File nf = new File(new String(cc));
            if (!f.renameTo(nf)) {
                /*there is a known issue that renameTo fails if
                  (1)the path is a UNC path and
                  (2)the path length is bigger than 1092
                  so don't stop if above are true
                */
                String abPath = f.getAbsolutePath();
                if (!abPath.startsWith("\\\\") ||
                    abPath.length() < 1093) {
                    throw new RuntimeException ("File.renameTo() failed for lenth="
                                                + abPath.length());
                }
            } else {
                if (!nf.canRead())
                    throw new RuntimeException ("Renamed file is not readable");
                if (!nf.canWrite())
                    throw new RuntimeException ("Renamed file is not writable");
                if (nf.length() != 1)
                    throw new RuntimeException ("Renamed file's size is not correct");
                if (!nf.renameTo(f)) {
                    created[0] = nf.getPath();
                }
                /* add a script to test these two if we got a regression later
                if (!f.setReadOnly())
                    throw new RuntimeException ("File.setReadOnly() failed");
                f.deleteOnExit();
                */
            }
        } finally {
            // Clean up
            for (int i = 0; i < max; i++) {
                Path p = (new File(created[i])).toPath();
                try {
                    Files.deleteIfExists(p);
                    // Test if the file is really deleted and wait for 1 second at most
                    for (int j = 0; j < 10 && Files.exists(p); j++) {
                        Thread.sleep(100);
                    }
                } catch (DirectoryNotEmptyException ex) {
                    // Give up the clean-up, let jtreg handle it.
                    System.err.println("Dir, " + p + ", is not empty");
                    break;
                }
            }
        }
    }
}