org.eredlab.g4.ccl.net.ftp.parser.FTPTimestampParserImpl.java Source code

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/*
 * Copyright 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.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.eredlab.g4.ccl.net.ftp.Configurable;
import org.eredlab.g4.ccl.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 {

    private SimpleDateFormat defaultDateFormat;
    private SimpleDateFormat recentDateFormat;

    /**
     * The only constructor for this class. 
     */
    public FTPTimestampParserImpl() {
        setDefaultDateFormat(DEFAULT_SDF);
        setRecentDateFormat(DEFAULT_RECENT_SDF);
    }

    /** 
     * 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. 
     * 
     * @see org.apache.commons.net.ftp.parser.FTPTimestampParser#parseTimestamp(java.lang.String)    
     */
    /* (non-Javadoc)
     * 
     */
    public Calendar parseTimestamp(String timestampStr) throws ParseException {
        Calendar now = Calendar.getInstance();
        now.setTimeZone(this.getServerTimeZone());

        Calendar working = Calendar.getInstance();
        working.setTimeZone(this.getServerTimeZone());
        ParsePosition pp = new ParsePosition(0);

        Date parsed = null;
        if (this.recentDateFormat != null) {
            parsed = recentDateFormat.parse(timestampStr, pp);
        }
        if (parsed != null && pp.getIndex() == timestampStr.length()) {
            working.setTime(parsed);
            working.set(Calendar.YEAR, now.get(Calendar.YEAR));
            if (working.after(now)) {
                working.add(Calendar.YEAR, -1);
            }
        } else {
            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()) {
                working.setTime(parsed);
            } else {
                throw new ParseException("Timestamp could not be parsed with older or recent DateFormat",
                        pp.getIndex());
            }
        }
        return working;
    }

    /**
     * @return Returns the defaultDateFormat.
     */
    public SimpleDateFormat getDefaultDateFormat() {
        return defaultDateFormat;
    }

    /**
     * @return Returns the defaultDateFormat pattern string.
     */
    public String getDefaultDateFormatString() {
        return defaultDateFormat.toPattern();
    }

    /**
     * @param defaultDateFormat The defaultDateFormat to be set.
     */
    private void setDefaultDateFormat(String format) {
        if (format != null) {
            this.defaultDateFormat = new SimpleDateFormat(format);
            this.defaultDateFormat.setLenient(false);
        }
    }

    /**
     * @return Returns the recentDateFormat.
     */
    public SimpleDateFormat getRecentDateFormat() {
        return recentDateFormat;
    }

    /**
     * @return Returns the recentDateFormat.
     */
    public String getRecentDateFormatString() {
        return recentDateFormat.toPattern();
    }

    /**
     * @param recentDateFormat The recentDateFormat to set.
     */
    private void setRecentDateFormat(String format) {
        if (format != null) {
            this.recentDateFormat = new SimpleDateFormat(format);
            this.recentDateFormat.setLenient(false);
        }
    }

    /**
     * @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 serverTimeZone used by this parser.
     */
    public TimeZone getServerTimeZone() {
        return this.defaultDateFormat.getTimeZone();
    }

    /**
     * sets a TimeZone represented by the supplied ID string into all
     * of the parsers used by this server.
     * @param serverTimeZone Time Id java.util.TimeZone id used by
     * the ftp server.  If null the client's local time zone is assumed.
     */
    private void setServerTimeZone(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);
        }
    }

    /**
     * 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><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><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> 
     */
    public void configure(FTPClientConfig config) {
        DateFormatSymbols dfs = null;

        String languageCode = config.getServerLanguageCode();
        String shortmonths = config.getShortMonthNames();
        if (shortmonths != null) {
            dfs = FTPClientConfig.getDateFormatSymbols(shortmonths);
        } else if (languageCode != null) {
            dfs = FTPClientConfig.lookupDateFormatSymbols(languageCode);
        } else {
            dfs = FTPClientConfig.lookupDateFormatSymbols("en");
        }

        String recentFormatString = config.getRecentDateFormatStr();
        if (recentFormatString == null) {
            this.recentDateFormat = null;
        } else {
            this.recentDateFormat = new SimpleDateFormat(recentFormatString, dfs);
            this.recentDateFormat.setLenient(false);
        }

        String defaultFormatString = config.getDefaultDateFormatStr();
        if (defaultFormatString == null) {
            throw new IllegalArgumentException("defaultFormatString cannot be null");
        }
        this.defaultDateFormat = new SimpleDateFormat(defaultFormatString, dfs);
        this.defaultDateFormat.setLenient(false);

        setServerTimeZone(config.getServerTimeZoneId());
    }
}