package ie.dcu.util;

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

/**
 * Utility functions for <code>.properties</code> files.
 * 
 * @author Kevin McGuinness
 */
public class PropsUtils {
	
	/**
	 * Save the properties object to a file.
	 * 
	 * @param props
	 *          The properties.
	 * @param file
	 *          The file to save it to.
	 * @throws IOException
	 *           If there is an error saving.
	 */
	public static void save(Properties props, File file) throws IOException {	
		OutputStream out = null;
		
		try {
			out = new BufferedOutputStream(new FileOutputStream(file));
			props.store(out, "Automatically generated properties file");
			
		} finally {
			
			if (out != null) out.close();
		}
	}
	
	
	/**
	 * Load the properties object from a file.
	 * 
	 * @param file
	 *          The file.
	 * @return A new properties object.
	 * @throws IOException
	 *           If an error occurs loading the properties.
	 */
	public static Properties load(File file) throws IOException {
		InputStream in = null;
		Properties props = null;
		
		try {
			in = new BufferedInputStream(new FileInputStream(file));
			props = new Properties();
			props.load(in);
			
		} finally {
			
			if (in != null) in.close();
		}
		
		return props;
	}
	
	
	public static File getFile(Properties props, String key) {
		String val = props.getProperty(key);
		if (val != null) {
			return new File(val);
		}
		return null;
	}
}