panda.net.ftp.parser.VMSVersioningFTPEntryParser Maven / Gradle / Ivy

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Panda Core is the core module of Panda Framework, it contains commonly used utility classes similar to apache-commons.
There is a newer version: 1.8.0
package panda.net.ftp.parser;

import java.util.HashMap;
import java.util.List;
import java.util.ListIterator;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import panda.net.ftp.FTPClientConfig;

/**
 * Special implementation VMSFTPEntryParser with versioning turned on. This parser removes all
 * duplicates and only leaves the version with the highest version number for each filename. This is
 * a sample of VMS LIST output
 * "1-JUN.LIS;1              9/9           2-JUN-1998 07:32:04  [GROUP,OWNER]    (RWED,RWED,RWED,RE)"
 * ,
 * "1-JUN.LIS;2              9/9           2-JUN-1998 07:32:04  [GROUP,OWNER]    (RWED,RWED,RWED,RE)"
 * ,
 * "DATA.DIR;1               1/9           2-JUN-1998 07:32:04  [GROUP,OWNER]    (RWED,RWED,RWED,RE)"
 * ,
 * 
 * 
 * @version $Id: VMSVersioningFTPEntryParser.java 1697293 2015-08-24 01:01:00Z sebb $
 * @see panda.net.ftp.FTPFileEntryParser FTPFileEntryParser (for usage instructions)
 */
public class VMSVersioningFTPEntryParser extends VMSFTPEntryParser {

	private final Pattern _preparse_pattern_;
	private static final String PRE_PARSE_REGEX = "(.*?);([0-9]+)\\s*.*";

	/**
	 * Constructor for a VMSFTPEntryParser 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
	 *                REGEX is not a valid regular expression.
	 */
	public VMSVersioningFTPEntryParser() {
		this(null);
	}

	/**
	 * This constructor allows the creation of a VMSVersioningFTPEntryParser 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
	 *                REGEX is not a valid regular expression.
	 */
	public VMSVersioningFTPEntryParser(FTPClientConfig config) {
		super();
		configure(config);
		try {
			// _preparse_matcher_ = new Perl5Matcher();
			_preparse_pattern_ = Pattern.compile(PRE_PARSE_REGEX);
		}
		catch (PatternSyntaxException pse) {
			throw new IllegalArgumentException("Unparseable regex supplied:  " + PRE_PARSE_REGEX);
		}

	}

	/**
	 * Implement hook provided for those implementers (such as VMSVersioningFTPEntryParser, and
	 * possibly others) which return multiple files with the same name to remove the duplicates ..
	 * 
	 * @param original Original list
	 * @return Original list purged of duplicates
	 */
	@Override
	public List preParse(List original) {
		HashMap existingEntries = new HashMap();
		ListIterator iter = original.listIterator();
		while (iter.hasNext()) {
			String entry = iter.next().trim();
			MatchResult result = null;
			Matcher _preparse_matcher_ = _preparse_pattern_.matcher(entry);
			if (_preparse_matcher_.matches()) {
				result = _preparse_matcher_.toMatchResult();
				String name = result.group(1);
				String version = result.group(2);
				Integer nv = Integer.valueOf(version);
				Integer existing = existingEntries.get(name);
				if (null != existing) {
					if (nv.intValue() < existing.intValue()) {
						iter.remove(); // removes older version from original list.
						continue;
					}
				}
				existingEntries.put(name, nv);
			}

		}
		// we've now removed all entries less than with less than the largest
		// version number for each name that were listed after the largest.
		// we now must remove those with smaller than the largest version number
		// for each name that were found before the largest
		while (iter.hasPrevious()) {
			String entry = iter.previous().trim();
			MatchResult result = null;
			Matcher _preparse_matcher_ = _preparse_pattern_.matcher(entry);
			if (_preparse_matcher_.matches()) {
				result = _preparse_matcher_.toMatchResult();
				String name = result.group(1);
				String version = result.group(2);
				Integer nv = Integer.valueOf(version);
				Integer existing = existingEntries.get(name);
				if (null != existing) {
					if (nv.intValue() < existing.intValue()) {
						iter.remove(); // removes older version from original list.
					}
				}
			}

		}
		return original;
	}

	@Override
	protected boolean isVersioning() {
		return true;
	}

}

/*
 * Emacs configuration Local variables: ** mode: java ** c-basic-offset: 4 ** indent-tabs-mode: nil
 * ** End: **
 */