/*
 * 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.ParseException;
import java.util.Calendar;

import org.apache.commons.net.ftp.Configurable;
import org.apache.commons.net.ftp.FTPClientConfig;


/**
 * <p>
 * This abstract class implements the common timestamp parsing
 * algorithm for all the concrete parsers.  Classes derived from
 * this one will parse file listings via a supplied regular expression
 * that pulls out the date portion as a separate string which is
 * passed to the underlying {@link FTPTimestampParser delegate} to
 * handle parsing of the file timestamp.
 * </p><p>
 * This class also implements the {@link Configurable Configurable}
 * interface to allow the parser to be configured from the outside.
 * </p>
 * @since 1.4
 */
/**
 * To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates - Comments
 */
public abstract class ConfigurableFTPFileEntryParserImpl 
extends RegexFTPFileEntryParserImpl 
implements Configurable 
{

    private FTPTimestampParser timestampParser;
    
    /**
     * Only constructor for this absract class.
     * @param regex  Regular expression used main parsing of the 
     * file listing.
     */
    public ConfigurableFTPFileEntryParserImpl(String regex)
    {
        super(regex);
        this.timestampParser = new FTPTimestampParserImpl();
    }

    /**
     * This method is called by the concrete parsers to delegate
     * timestamp parsing to the timestamp parser.
     * <p>
     * @param timestampStr the timestamp string pulled from the 
     * file listing by the regular expression parser, to be submitted
     * to the <code>timestampParser</code> for extracting the timestamp.
     * @return a <code>java.util.Calendar</code> containing results of the 
     * timestamp parse. 
     */
    public Calendar parseTimestamp(String timestampStr) throws ParseException {
        return this.timestampParser.parseTimestamp(timestampStr);
    }


    /**
     * Implementation of the {@link  Configurable  Configurable}
     * interface. Configures this parser by delegating to the
     * underlying Configurable FTPTimestampParser implementation, '
     * passing it the supplied {@link  FTPClientConfig FTPClientConfig}
     * if that is non-null or a default configuration defined by
     * each concrete subclass.
     * </p> 
     * @param config the configuration to be used to configure this parser.
     * If it is null, a default configuration defined by
     * each concrete subclass is used instead.
     */
    public void configure(FTPClientConfig config)
    {
        if (this.timestampParser instanceof Configurable) {
            FTPClientConfig defaultCfg = getDefaultConfiguration();
            if (config != null) {
                if (null == config.getDefaultDateFormatStr()) {
                    config.setDefaultDateFormatStr(defaultCfg.getDefaultDateFormatStr());
                }
                if (null == config.getRecentDateFormatStr()) {
                    config.setRecentDateFormatStr(defaultCfg.getRecentDateFormatStr());
                }
                ((Configurable)this.timestampParser).configure(config);
            } else {
                ((Configurable)this.timestampParser).configure(defaultCfg);
            }
        }
    }
    
    /**
     * Each concrete subclass must define this member to create
     * a default configuration to be used when that subclass is
     * instantiated without a {@link  FTPClientConfig  FTPClientConfig}
     * parameter being specified.
     * @return the default configuration for the subclass.
     */
    protected abstract FTPClientConfig getDefaultConfiguration();
}