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Commons Net example source code file (UnixFTPEntryParser.java)

This example Commons Net source code file (UnixFTPEntryParser.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Net tags/keywords

default_date_format, default_recent_date_format, ftpclientconfig, ftpclientconfig, ftpfile, ftpfile, mmm, nov, override, s+, string, string, text, unixftpentryparser, unixftpentryparser, util

The Commons Net UnixFTPEntryParser.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.net.ftp.parser;
import java.text.ParseException;
import java.util.List;
import java.util.ListIterator;

import org.apache.commons.net.ftp.FTPClientConfig;
import org.apache.commons.net.ftp.FTPFile;

/**
 * Implementation FTPFileEntryParser and FTPFileListParser for standard
 * Unix Systems.
 *
 * This class is based on the logic of Daniel Savarese's
 * DefaultFTPListParser, but adapted to use regular expressions and to fit the
 * new FTPFileEntryParser interface.
 * @version $Id: UnixFTPEntryParser.java 1084428 2011-03-23 00:46:12Z sebb $
 * @see org.apache.commons.net.ftp.FTPFileEntryParser FTPFileEntryParser (for usage instructions)
 */
public class UnixFTPEntryParser extends ConfigurableFTPFileEntryParserImpl
{

    static final String DEFAULT_DATE_FORMAT
        = "MMM d yyyy"; //Nov 9 2001

    static final String DEFAULT_RECENT_DATE_FORMAT
        = "MMM d HH:mm"; //Nov 9 20:06

    static final String NUMERIC_DATE_FORMAT
        = "yyyy-MM-dd HH:mm"; //2001-11-09 20:06

    /**
     * Some Linux distributions are now shipping an FTP server which formats
     * file listing dates in an all-numeric format:
     * <code>"yyyy-MM-dd HH:mm.
     * This is a very welcome development,  and hopefully it will soon become
     * the standard.  However, since it is so new, for now, and possibly
     * forever, we merely accomodate it, but do not make it the default.
     * <p>
     * For now end users may specify this format only via
     * <code>UnixFTPEntryParser(FTPClientConfig).
     * Steve Cohen - 2005-04-17
     */
    public static final FTPClientConfig NUMERIC_DATE_CONFIG =
        new FTPClientConfig(
                FTPClientConfig.SYST_UNIX,
                NUMERIC_DATE_FORMAT,
                null, null, null, null);

    /**
     * this is the regular expression used by this parser.
     *
     * Permissions:
     *    r   the file is readable
     *    w   the file is writable
     *    x   the file is executable
     *    -   the indicated permission is not granted
     *    L   mandatory locking occurs during access (the set-group-ID bit is
     *        on and the group execution bit is off)
     *    s   the set-user-ID or set-group-ID bit is on, and the corresponding
     *        user or group execution bit is also on
     *    S   undefined bit-state (the set-user-ID bit is on and the user
     *        execution bit is off)
     *    t   the 1000 (octal) bit, or sticky bit, is on [see chmod(1)], and
     *        execution is on
     *    T   the 1000 bit is turned on, and execution is off (undefined bit-
     *        state)
     *    e   z/OS external link bit
     */
    private static final String REGEX =
        "([bcdelfmpSs-])"
        +"(((r|-)(w|-)([xsStTL-]))((r|-)(w|-)([xsStTL-]))((r|-)(w|-)([xsStTL-])))\\+?\\s*"
        + "(\\d+)\\s+"                                  // link count
        + "(?:(\\S+(?:\\s\\S+)*?)\\s+)?"                // owner name (optional spaces)
        + "(?:(\\S+(?:\\s\\S+)*)\\s+)?"                 // group name (optional spaces)
        + "(\\d+(?:,\\s*\\d+)?)\\s+"                    // size or n,m
        /*
         * numeric or standard format date:
         *   yyyy-mm-dd (expecting hh:mm to follow)
         *   MMM [d]d
         *   [d]d MMM
         *   N.B. use non-space for MMM to allow for languages such as German which use
         *   diacritics (e.g. umlaut) in some abbreviations.
        */
        + "((?:\\d+[-/]\\d+[-/]\\d+)|(?:\\S{3}\\s+\\d{1,2})|(?:\\d{1,2}\\s+\\S{3}))\\s+"
        /*
           year (for non-recent standard format) - yyyy
           or time (for numeric or recent standard format) [h]h:mm
        */
        + "(\\d+(?::\\d+)?)\\s+"

        + "(\\S*)(\\s*.*)"; // the rest


    /**
     * The default constructor for a UnixFTPEntryParser object.
     *
     * @exception IllegalArgumentException
     * Thrown if the regular expression is unparseable.  Should not be seen
     * under normal conditions.  It it is seen, this is a sign that
     * <code>REGEX is  not a valid regular expression.
     */
    public UnixFTPEntryParser()
    {
        this(null);
    }

    /**
     * This constructor allows the creation of a UnixFTPEntryParser object with
     * something other than the default configuration.
     *
     * @param config The {@link FTPClientConfig configuration} object used to
     * configure this parser.
     * @exception IllegalArgumentException
     * Thrown if the regular expression is unparseable.  Should not be seen
     * under normal conditions.  It it is seen, this is a sign that
     * <code>REGEX is  not a valid regular expression.
     * @since 1.4
     */
    public UnixFTPEntryParser(FTPClientConfig config)
    {
        super(REGEX);
        configure(config);
    }

    /**
     * Preparse the list to discard "total nnn" lines
     */
    @Override
    public List<String> preParse(List original) {
        ListIterator<String> iter = original.listIterator();
        while (iter.hasNext()) {
            String entry = iter.next();
            if (entry.matches("^total \\d+$")) { // NET-389
                iter.remove();
            }
        }
        return original;
    }

    /**
     * Parses a line of a unix (standard) FTP server file listing and converts
     * it into a usable format in the form of an <code> FTPFile 
     * instance.  If the file listing line doesn't describe a file,
     * <code> null  is returned, otherwise a  FTPFile 
     * instance representing the files in the directory is returned.
     * <p>
     * @param entry A line of text from the file listing
     * @return An FTPFile instance corresponding to the supplied entry
     */
    public FTPFile parseFTPEntry(String entry) {
        FTPFile file = new FTPFile();
        file.setRawListing(entry);
        int type;
        boolean isDevice = false;

        if (matches(entry))
        {
            String typeStr = group(1);
            String hardLinkCount = group(15);
            String usr = group(16);
            String grp = group(17);
            String filesize = group(18);
            String datestr = group(19) + " " + group(20);
            String name = group(21);
            String endtoken = group(22);

            try
            {
                file.setTimestamp(super.parseTimestamp(datestr));
            }
            catch (ParseException e)
            {
                 // intentionally do nothing
            }

            // A 'whiteout' file is an ARTIFICIAL entry in any of several types of
            // 'translucent' filesystems, of which a 'union' filesystem is one.

            // bcdelfmpSs-
            switch (typeStr.charAt(0))
            {
            case 'd':
                type = FTPFile.DIRECTORY_TYPE;
                break;
            case 'e': // NET-39 => z/OS external link
                type = FTPFile.SYMBOLIC_LINK_TYPE;
                break;
            case 'l':
                type = FTPFile.SYMBOLIC_LINK_TYPE;
                break;
            case 'b':
            case 'c':
                isDevice = true;
                // break; - fall through
                //$FALL-THROUGH$ TODO change this if DEVICE_TYPE implemented
            case 'f':
            case '-':
                type = FTPFile.FILE_TYPE;
                break;
            default: // e.g. ? and w = whiteout
                type = FTPFile.UNKNOWN_TYPE;
            }

            file.setType(type);

            int g = 4;
            for (int access = 0; access < 3; access++, g += 4)
            {
                // Use != '-' to avoid having to check for suid and sticky bits
                file.setPermission(access, FTPFile.READ_PERMISSION,
                                   (!group(g).equals("-")));
                file.setPermission(access, FTPFile.WRITE_PERMISSION,
                                   (!group(g + 1).equals("-")));

                String execPerm = group(g + 2);
                if (!execPerm.equals("-") && !Character.isUpperCase(execPerm.charAt(0)))
                {
                    file.setPermission(access, FTPFile.EXECUTE_PERMISSION, true);
                }
                else
                {
                    file.setPermission(access, FTPFile.EXECUTE_PERMISSION, false);
                }
            }

            if (!isDevice)
            {
                try
                {
                    file.setHardLinkCount(Integer.parseInt(hardLinkCount));
                }
                catch (NumberFormatException e)
                {
                    // intentionally do nothing
                }
            }

            file.setUser(usr);
            file.setGroup(grp);

            try
            {
                file.setSize(Long.parseLong(filesize));
            }
            catch (NumberFormatException e)
            {
                // intentionally do nothing
            }

            if (null == endtoken)
            {
                file.setName(name);
            }
            else
            {
                // oddball cases like symbolic links, file names
                // with spaces in them.
                name += endtoken;
                if (type == FTPFile.SYMBOLIC_LINK_TYPE)
                {

                    int end = name.indexOf(" -> ");
                    // Give up if no link indicator is present
                    if (end == -1)
                    {
                        file.setName(name);
                    }
                    else
                    {
                        file.setName(name.substring(0, end));
                        file.setLink(name.substring(end + 4));
                    }

                }
                else
                {
                    file.setName(name);
                }
            }
            return file;
        }
        return null;
    }

    /**
     * Defines a default configuration to be used when this class is
     * instantiated without a {@link  FTPClientConfig  FTPClientConfig}
     * parameter being specified.
     * @return the default configuration for this parser.
     */
    @Override
    protected FTPClientConfig getDefaultConfiguration() {
        return new FTPClientConfig(
                FTPClientConfig.SYST_UNIX,
                DEFAULT_DATE_FORMAT,
                DEFAULT_RECENT_DATE_FORMAT,
                null, null, null);
    }

}

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