/*
** Java currency library package.
** Copyright (c) 1999 by Bruno Antunes
**
** This program is free software.
**
** You may redistribute it and/or modify it under the terms of the GNU
** General Public License as published by the Free Software Foundation.
** Version 2 of the license should be included with this distribution in
** the file LICENSE, as well as License.html. If the license is not
** included	with this distribution, you may find a copy at the FSF web
** site at 'www.gnu.org' or 'www.fsf.org', or you may write to the
** Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139 USA.
**
** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
** REDISTRIBUTION OF THIS SOFTWARE.
**
*/
package org.gjt.currency;

import java.util.*;
import java.io.*;

/**
 * Utility to read properties list
 *
 * @author Bruno Antunes
 * @version 1.0 7/05/1999
 */
public class PropertiesHelper {

    /**
    * Reads a property list (key and element pairs) using this base class with a
    * properties list file name.
    *
    * @param propName the name of the properties file to read
    * @return the Properties
    * @see Class#getResourceAsStream
    * @throws IOException if an error occurred when reading from the
    * properties list.
    */
    public static final Properties loadProperties(String propName)
            throws IOException {
        return loadProperties(PropertiesHelper.class, propName);
    }

    /**
     * Reads a property list (key and element pairs) from a base class with a
     * properties list file name.
     *
     * @param clasz the Class to use do load the properties list using the
     * getResourceAsStream method
     * @param propName the name of the properties file to read
     * @return the Properties
     * @see Class#getResourceAsStream
     * @throws IOException if an error occurred when reading from the
     * properties list.
     */
    public static final Properties loadProperties(Class clasz, String propName)
            throws IOException {
        if ((clasz == null) || (propName == null)) {
            throw new IllegalArgumentException("Invalid arguments");
        }
        Properties p = new Properties();
        InputStream is = null;

        try {
            is = clasz.getResourceAsStream(propName);
            if (is == null) {
                throw new IOException("Properties not found: " + propName);
            } else {
                p.load(is);
            }
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException ignored) {
                }
            }
        }
        return p;
    }

    /**
     * Reads a property list (key and element pairs) from the input stream
     *
     * @param a string with the format [<key>=<value>]
     * [,<key>=<value>]*
     * @return the Properties
     * @throws IOException if an error occurred when reading from the
     * input stream.
     * @throws IllegalArgumentException if an invalid imput stream is passed
     */
    public static final Properties loadProperties(InputStream is)
            throws IOException {
        Properties p = new Properties();
        try {
            if (is == null) {
                throw new IllegalArgumentException("Invalid InputStream: null");
            } else {
                p.load(is);
            }
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException ignored) {
                }
            }
        }
        return p;
    }

    /**
     * Reads a property list (key and element pairs) from a string
     * representation
     *
     * @param a string with the format [<key>=<value>]
     * [,<key>=<value>]*
     * @return the Properties
     * @throws IllegalArgumentException if an invalid string token is passed
     */
    public static final Properties loadTokenizedProperties(String tokens) {
        if (tokens == null) {
            throw new IllegalArgumentException("Invalid propertie definition:" +
                                               " null");
        }
        StringTokenizer token = new StringTokenizer(tokens,",");
        Properties p = new Properties();
        StringTokenizer entry;
        while (token.hasMoreTokens()) {
            entry = new StringTokenizer(token.nextToken(),"=");
            if (entry.countTokens() != 2) {
                throw new IllegalArgumentException("Invalid tokenized " +
                                                   "propertie entry");
            }
            p.put(entry.nextToken(),entry.nextToken());
        }
        return p;
    }
}