/*
 * ftp4j - A pure Java FTP client library
 * 
 * Copyright (C) 2008-2010 Carlo Pelliccia (www.sauronsoftware.it)
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version
 * 2.1, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License 2.1 for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License version 2.1 along with this program.
 * If not, see <http://www.gnu.org/licenses/>.
 */
package it.sauronsoftware.ftp4j.extrecognizers;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

/**
 * <p>
 * This is the default FTPTextualExtensionRecognizer for every new FTPClient
 * object. It recognizes as textual these extensions:
 * </p>
 * 
 * <pre>
 * abc acgi aip asm asp c c cc cc com conf cpp csh css cxx def el etx f f f77
 * f90 f90 flx for for g h h hh hh hlb htc htm html htmls htt htx idc jav jav
 * java java js ksh list log lsp lst lsx m m mar mcf p pas php pl pl pm py rexx
 * rt rt rtf rtx s scm scm sdml sgm sgm sgml sgml sh shtml shtml spc ssi talk
 * tcl tcsh text tsv txt uil uni unis uri uris uu uue vcs wml wmls wsc xml zsh
 * </pre>
 * 
 * <p>
 * These extensions are loaded from the file textualexts within the package. The
 * file can be manipulated to add or remove extensions, but it's more convenient
 * to plug a ParametricTextualExtensionRecognizer instance in the client.
 * </p>
 * 
 * @author Carlo Pelliccia
 */
public class DefaultTextualExtensionRecognizer extends
		ParametricTextualExtensionRecognizer {

	/**
	 * Lock object.
	 */
	private static final Object lock = new Object();

	/**
	 * The singleton instance.
	 */
	private static DefaultTextualExtensionRecognizer instance = null;

	/**
	 * This one returns the default instance of the class.
	 * 
	 * @return An instance of the class.
	 */
	public static DefaultTextualExtensionRecognizer getInstance() {
		synchronized (lock) {
			if (instance == null) {
				instance = new DefaultTextualExtensionRecognizer();
			}
		}
		return instance;
	}

	/**
	 * It builds the instance.
	 */
	private DefaultTextualExtensionRecognizer() {
		BufferedReader r = null;
		try {
			r = new BufferedReader(new InputStreamReader(getClass()
					.getResourceAsStream("textualexts")));
			String line;
			while ((line = r.readLine()) != null) {
				StringTokenizer st = new StringTokenizer(line);
				while (st.hasMoreTokens()) {
					addExtension(st.nextToken());
				}
			}
		} catch (Exception e) {
			;
		} finally {
			if (r != null) {
				try {
					r.close();
				} catch (Throwable t) {
					;
				}
			}
		}
	}

}