VMSVersioningFTPEntryParser.java
- /*
- * 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.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 org.apache.commons.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 file name.
- * <p>
- * This is a sample of VMS LIST output
- * </p>
- *
- * <pre>
- * "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)",
- * </pre>
- *
- * @see org.apache.commons.net.ftp.FTPFileEntryParser FTPFileEntryParser (for usage instructions)
- */
- public class VMSVersioningFTPEntryParser extends VMSFTPEntryParser {
- /**
- * Guard against polynomial regular expression used on uncontrolled data.
- * Don't look for more than 20 digits for the version.
- * Don't look for more than 80 spaces after the version.
- * Don't look for more than 80 characters after the spaces.
- */
- private static final String REGEX = "(.*?);([0-9]{1,20})\\s{0,80}.{0,80}";
- private static final Pattern PATTERN = Pattern.compile(REGEX);
- /**
- * Constructor for a VMSFTPEntryParser object.
- *
- * @throws IllegalArgumentException Thrown if the regular expression is unparseable. Should not be seen under normal conditions. If the exception 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.
- * @throws IllegalArgumentException Thrown if the regular expression is unparseable. Should not be seen under normal conditions. If the exception is seen,
- * this is a sign that <code>REGEX</code> is not a valid regular expression.
- * @since 1.4
- */
- public VMSVersioningFTPEntryParser(final FTPClientConfig config) {
- configure(config);
- }
- @Override
- protected boolean isVersioning() {
- return true;
- }
- /**
- * 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<String> preParse(final List<String> original) {
- final HashMap<String, Integer> existingEntries = new HashMap<>();
- final ListIterator<String> iter = original.listIterator();
- while (iter.hasNext()) {
- final String entry = iter.next().trim();
- MatchResult result;
- final Matcher matcher = PATTERN.matcher(entry);
- if (matcher.matches()) {
- result = matcher.toMatchResult();
- final String name = result.group(1);
- final String version = result.group(2);
- final Integer nv = Integer.valueOf(version);
- final Integer existing = existingEntries.get(name);
- if (null != existing && 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()) {
- final String entry = iter.previous().trim();
- MatchResult result = null;
- final Matcher matcher = PATTERN.matcher(entry);
- if (matcher.matches()) {
- result = matcher.toMatchResult();
- final String name = result.group(1);
- final String version = result.group(2);
- final int nv = Integer.parseInt(version);
- final Integer existing = existingEntries.get(name);
- if (null != existing && nv < existing.intValue()) {
- iter.remove(); // removes older version from original list.
- }
- }
- }
- return original;
- }
- }