Java tutorial
/* * Copyright 2001-2005 The Apache Software Foundation * * Licensed 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.eredlab.g4.ccl.net.ftp.parser; import java.util.HashMap; import java.util.List; import java.util.ListIterator; import org.apache.oro.text.regex.MalformedPatternException; import org.apache.oro.text.regex.MatchResult; import org.apache.oro.text.regex.Pattern; import org.apache.oro.text.regex.Perl5Compiler; import org.apache.oro.text.regex.Perl5Matcher; import org.eredlab.g4.ccl.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)", * <P> * * @author <a href="Winston.Ojeda@qg.com">Winston Ojeda</a> * @author <a href="sestegra@free.fr">Stephane ESTE-GRACIAS</a> * @version $Id: VMSVersioningFTPEntryParser.java 155429 2005-02-26 13:13:04Z dirkv $ * * @see org.apache.commons.net.ftp.FTPFileEntryParser FTPFileEntryParser (for usage instructions) */ public class VMSVersioningFTPEntryParser extends VMSFTPEntryParser { private Perl5Matcher _preparse_matcher_; private Pattern _preparse_pattern_; private static final String PRE_PARSE_REGEX = "(.*);([0-9]+)\\s*.*"; /** * Constructor for a VMSFTPEntryParser object. Sets the versioning member * to the supplied value. * * @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</code> 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 * <code>REGEX</code> is not a valid regular expression. * @since 1.4 */ public VMSVersioningFTPEntryParser(FTPClientConfig config) { super(); configure(config); try { _preparse_matcher_ = new Perl5Matcher(); _preparse_pattern_ = new Perl5Compiler().compile(PRE_PARSE_REGEX); } catch (MalformedPatternException e) { throw new IllegalArgumentException("Unparseable regex supplied: " + PRE_PARSE_REGEX); } } private class NameVersion { String name; int versionNumber; NameVersion(String name, String vers) { this.name = name; this.versionNumber = Integer.parseInt(vers); } } /** * 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 */ public List preParse(List original) { original = super.preParse(original); HashMap existingEntries = new HashMap(); ListIterator iter = original.listIterator(); while (iter.hasNext()) { String entry = ((String) iter.next()).trim(); MatchResult result = null; if (_preparse_matcher_.matches(entry, _preparse_pattern_)) { result = _preparse_matcher_.getMatch(); String name = result.group(1); String version = result.group(2); NameVersion nv = new NameVersion(name, version); NameVersion existing = (NameVersion) existingEntries.get(name); if (null != existing) { if (nv.versionNumber < existing.versionNumber) { iter.remove(); // removal removes 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 = ((String) iter.previous()).trim(); MatchResult result = null; if (_preparse_matcher_.matches(entry, _preparse_pattern_)) { result = _preparse_matcher_.getMatch(); String name = result.group(1); String version = result.group(2); NameVersion nv = new NameVersion(name, version); NameVersion existing = (NameVersion) existingEntries.get(name); if (null != existing) { if (nv.versionNumber < existing.versionNumber) { iter.remove(); // removal removes from original list. } } } } return original; } protected boolean isVersioning() { return true; } } /* Emacs configuration * Local variables: ** * mode: java ** * c-basic-offset: 4 ** * indent-tabs-mode: nil ** * End: ** */