FTPTimestampParserImpl.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.text.DateFormatSymbols;
import java.text.ParseException;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
import org.apache.commons.net.ftp.Configurable;
import org.apache.commons.net.ftp.FTPClientConfig;
/**
* Default implementation of the {@link FTPTimestampParser FTPTimestampParser} interface also implements the {@link org.apache.commons.net.ftp.Configurable
* Configurable} interface to allow the parsing to be configured from the outside.
*
* @see ConfigurableFTPFileEntryParserImpl
* @since 1.4
*/
public class FTPTimestampParserImpl implements FTPTimestampParser, Configurable {
/*
* List of units in order of increasing significance. This allows the code to clear all units in the Calendar until it reaches the least significant unit in
* the parse string. The date formats are analysed to find the least significant unit (e.g. Minutes or Milliseconds) and the appropriate index to the array
* is saved. This is done by searching the array for the unit specifier, and returning the index. When clearing the Calendar units, the code loops through
* the array until the previous entry. e.g. for MINUTE it would clear MILLISECOND and SECOND
*/
private static final int[] CALENDAR_UNITS = { Calendar.MILLISECOND, Calendar.SECOND, Calendar.MINUTE, Calendar.HOUR_OF_DAY, Calendar.DAY_OF_MONTH,
Calendar.MONTH, Calendar.YEAR };
/*
* Return the index to the array representing the least significant unit found in the date format. Default is 0 (to avoid dropping precision)
*/
private static int getEntry(final SimpleDateFormat dateFormat) {
if (dateFormat == null) {
return 0;
}
final String FORMAT_CHARS = "SsmHdM";
final String pattern = dateFormat.toPattern();
for (final char ch : FORMAT_CHARS.toCharArray()) {
if (pattern.indexOf(ch) != -1) { // found the character
switch (ch) {
case 'S':
return indexOf(Calendar.MILLISECOND);
case 's':
return indexOf(Calendar.SECOND);
case 'm':
return indexOf(Calendar.MINUTE);
case 'H':
return indexOf(Calendar.HOUR_OF_DAY);
case 'd':
return indexOf(Calendar.DAY_OF_MONTH);
case 'M':
return indexOf(Calendar.MONTH);
}
}
}
return 0;
}
/*
* Find the entry in the CALENDAR_UNITS array.
*/
private static int indexOf(final int calendarUnit) {
int i;
for (i = 0; i < CALENDAR_UNITS.length; i++) {
if (calendarUnit == CALENDAR_UNITS[i]) {
return i;
}
}
return 0;
}
/*
* Sets the Calendar precision (used by FTPFile#toFormattedDate) by clearing the immediately preceding unit (if any). Unfortunately the clear(int) method
* results in setting all other units.
*/
private static void setPrecision(final int index, final Calendar working) {
if (index <= 0) { // e.g. MILLISECONDS
return;
}
final int field = CALENDAR_UNITS[index - 1];
// Just in case the analysis is wrong, stop clearing if
// field value is not the default.
final int value = working.get(field);
if (value != 0) { // don't reset if it has a value
// new Throwable("Unexpected value "+value).printStackTrace(); // DEBUG
} else {
working.clear(field); // reset just the required field
}
}
/** The date format for all dates, except possibly recent dates. Assumed to include the year. */
private SimpleDateFormat defaultDateFormat;
/* The index in CALENDAR_UNITS of the smallest time unit in defaultDateFormat */
private int defaultDateSmallestUnitIndex;
/** The format used for recent dates (which don't have the year). May be null. */
private SimpleDateFormat recentDateFormat;
/* The index in CALENDAR_UNITS of the smallest time unit in recentDateFormat */
private int recentDateSmallestUnitIndex;
private boolean lenientFutureDates;
/**
* The only constructor for this class.
*/
public FTPTimestampParserImpl() {
setDefaultDateFormat(DEFAULT_SDF, null);
setRecentDateFormat(DEFAULT_RECENT_SDF, null);
}
/**
* Implementation of the {@link Configurable Configurable} interface. Configures this <code>FTPTimestampParser</code> according to the following logic:
* <p>
* Set up the {@link FTPClientConfig#setDefaultDateFormatStr(java.lang.String) defaultDateFormat} and optionally the
* {@link FTPClientConfig#setRecentDateFormatStr(String) recentDateFormat} to values supplied in the config based on month names configured as follows:
* </p>
* <ul>
* <li>If a {@link FTPClientConfig#setShortMonthNames(String) shortMonthString} has been supplied in the <code>config</code>, use that to parse parse
* timestamps.</li>
* <li>Otherwise, if a {@link FTPClientConfig#setServerLanguageCode(String) serverLanguageCode} has been supplied in the <code>config</code>, use the month
* names represented by that {@link FTPClientConfig#lookupDateFormatSymbols(String) language} to parse timestamps.</li>
* <li>otherwise use default English month names</li>
* </ul>
* <p>
* Finally if a {@link org.apache.commons.net.ftp.FTPClientConfig#setServerTimeZoneId(String) serverTimeZoneId} has been supplied via the config, set that
* into all date formats that have been configured.
* </p>
*/
@Override
public void configure(final FTPClientConfig config) {
DateFormatSymbols dfs;
final String languageCode = config.getServerLanguageCode();
final String shortmonths = config.getShortMonthNames();
if (shortmonths != null) {
dfs = FTPClientConfig.getDateFormatSymbols(shortmonths);
} else if (languageCode != null) {
dfs = FTPClientConfig.lookupDateFormatSymbols(languageCode);
} else {
dfs = FTPClientConfig.lookupDateFormatSymbols("en");
}
final String recentFormatString = config.getRecentDateFormatStr();
setRecentDateFormat(recentFormatString, dfs);
final String defaultFormatString = config.getDefaultDateFormatStr();
if (defaultFormatString == null) {
throw new IllegalArgumentException("defaultFormatString cannot be null");
}
setDefaultDateFormat(defaultFormatString, dfs);
setServerTimeZone(config.getServerTimeZoneId());
this.lenientFutureDates = config.isLenientFutureDates();
}
/**
* @return Returns the defaultDateFormat.
*/
public SimpleDateFormat getDefaultDateFormat() {
return defaultDateFormat;
}
/**
* @return Returns the defaultDateFormat pattern string.
*/
public String getDefaultDateFormatString() {
return defaultDateFormat.toPattern();
}
/**
* @return Returns the recentDateFormat.
*/
public SimpleDateFormat getRecentDateFormat() {
return recentDateFormat;
}
/**
* @return Returns the recentDateFormat.
*/
public String getRecentDateFormatString() {
return recentDateFormat.toPattern();
}
/**
* @return Returns the serverTimeZone used by this parser.
*/
public TimeZone getServerTimeZone() {
return this.defaultDateFormat.getTimeZone();
}
/**
* @return returns an array of 12 strings representing the short month names used by this parse.
*/
public String[] getShortMonths() {
return defaultDateFormat.getDateFormatSymbols().getShortMonths();
}
/**
* @return Returns the lenientFutureDates.
*/
boolean isLenientFutureDates() {
return lenientFutureDates;
}
/**
* Implements the one {@link FTPTimestampParser#parseTimestamp(String) method} in the {@link FTPTimestampParser FTPTimestampParser} interface according to
* this algorithm:
*
* If the recentDateFormat member has been defined, try to parse the supplied string with that. If that parse fails, or if the recentDateFormat member has
* not been defined, attempt to parse with the defaultDateFormat member. If that fails, throw a ParseException.
*
* This method assumes that the server time is the same as the local time.
*
* @see FTPTimestampParserImpl#parseTimestamp(String, Calendar)
*
* @param timestampStr The timestamp to be parsed
* @return a Calendar with the parsed timestamp
*/
@Override
public Calendar parseTimestamp(final String timestampStr) throws ParseException {
final Calendar now = Calendar.getInstance();
return parseTimestamp(timestampStr, now);
}
/**
* If the recentDateFormat member has been defined, try to parse the supplied string with that. If that parse fails, or if the recentDateFormat member has
* not been defined, attempt to parse with the defaultDateFormat member. If that fails, throw a ParseException.
*
* This method allows a {@link Calendar} instance to be passed in which represents the current (system) time.
*
* @see FTPTimestampParser#parseTimestamp(String)
* @param timestampStr The timestamp to be parsed
* @param serverTime The current time for the server
* @return the calendar
* @throws ParseException if timestamp cannot be parsed
* @since 1.5
*/
public Calendar parseTimestamp(final String timestampStr, final Calendar serverTime) throws ParseException {
final Calendar working = (Calendar) serverTime.clone();
working.setTimeZone(getServerTimeZone()); // is this needed?
Date parsed;
if (recentDateFormat != null) {
final Calendar now = (Calendar) serverTime.clone();// Copy this, because we may change it
now.setTimeZone(this.getServerTimeZone());
if (lenientFutureDates) {
// add a day to "now" so that "slop" doesn't cause a date
// slightly in the future to roll back a full year. (Bug 35181 => NET-83)
now.add(Calendar.DAY_OF_MONTH, 1);
}
// The Java SimpleDateFormat class uses the epoch year 1970 if not present in the input
// As 1970 was not a leap year, it cannot parse "Feb 29" correctly.
// Java 1.5+ returns Mar 1 1970
// Temporarily add the current year to the short date time
// to cope with short-date leap year strings.
// Since Feb 29 is more that 6 months from the end of the year, this should be OK for
// all instances of short dates which are +- 6 months from current date.
// TODO this won't always work for systems that use short dates +0/-12months
// e.g. if today is Jan 1 2001 and the short date is Feb 29
final String year = Integer.toString(now.get(Calendar.YEAR));
final String timeStampStrPlusYear = timestampStr + " " + year;
final SimpleDateFormat hackFormatter = new SimpleDateFormat(recentDateFormat.toPattern() + " yyyy", recentDateFormat.getDateFormatSymbols());
hackFormatter.setLenient(false);
hackFormatter.setTimeZone(recentDateFormat.getTimeZone());
final ParsePosition pp = new ParsePosition(0);
parsed = hackFormatter.parse(timeStampStrPlusYear, pp);
// Check if we parsed the full string, if so it must have been a short date originally
if (parsed != null && pp.getIndex() == timeStampStrPlusYear.length()) {
working.setTime(parsed);
if (working.after(now)) { // must have been last year instead
working.add(Calendar.YEAR, -1);
}
setPrecision(recentDateSmallestUnitIndex, working);
return working;
}
}
final ParsePosition pp = new ParsePosition(0);
parsed = defaultDateFormat.parse(timestampStr, pp);
// note, length checks are mandatory for us since
// SimpleDateFormat methods will succeed if less than
// full string is matched. They will also accept,
// despite "leniency" setting, a two-digit number as
// a valid year (e.g. 22:04 will parse as 22 A.D.)
// so could mistakenly confuse an hour with a year,
// if we don't insist on full length parsing.
if (parsed == null || pp.getIndex() != timestampStr.length()) {
throw new ParseException("Timestamp '" + timestampStr + "' could not be parsed using a server time of " + serverTime.getTime().toString(),
pp.getErrorIndex());
}
working.setTime(parsed);
setPrecision(defaultDateSmallestUnitIndex, working);
return working;
}
/**
* @param format The defaultDateFormat to be set.
* @param dfs the symbols to use (may be null)
*/
private void setDefaultDateFormat(final String format, final DateFormatSymbols dfs) {
if (format != null) {
if (dfs != null) {
this.defaultDateFormat = new SimpleDateFormat(format, dfs);
} else {
this.defaultDateFormat = new SimpleDateFormat(format);
}
this.defaultDateFormat.setLenient(false);
} else {
this.defaultDateFormat = null;
}
this.defaultDateSmallestUnitIndex = getEntry(this.defaultDateFormat);
}
/**
* @param lenientFutureDates The lenientFutureDates to set.
*/
void setLenientFutureDates(final boolean lenientFutureDates) {
this.lenientFutureDates = lenientFutureDates;
}
/**
* @param format The recentDateFormat to set.
* @param dfs the symbols to use (may be null)
*/
private void setRecentDateFormat(final String format, final DateFormatSymbols dfs) {
if (format != null) {
if (dfs != null) {
this.recentDateFormat = new SimpleDateFormat(format, dfs);
} else {
this.recentDateFormat = new SimpleDateFormat(format);
}
this.recentDateFormat.setLenient(false);
} else {
this.recentDateFormat = null;
}
this.recentDateSmallestUnitIndex = getEntry(this.recentDateFormat);
}
/**
* sets a TimeZone represented by the supplied ID string into all the parsers used by this server.
*
* @param serverTimeZoneId Time Id java.util.TimeZone id used by the ftp server. If null the client's local time zone is assumed.
*/
private void setServerTimeZone(final String serverTimeZoneId) {
TimeZone serverTimeZone = TimeZone.getDefault();
if (serverTimeZoneId != null) {
serverTimeZone = TimeZone.getTimeZone(serverTimeZoneId);
}
this.defaultDateFormat.setTimeZone(serverTimeZone);
if (this.recentDateFormat != null) {
this.recentDateFormat.setTimeZone(serverTimeZone);
}
}
}