FilenameURL.java

package sound.paulscode;

import java.net.MalformedURLException;
import java.net.URL;

import br.com.etyllica.util.io.IOHelper;

/**
 * The FilenameURL class is designed to associate a String filename/identifier
 * with a URL.  Handles either case where user supplies a String path or user
 * supplies a URL instance.
 *<br><br>
 *<b><i>    SoundSystem License:</b></i><br><b><br>
 *    You are free to use this library for any purpose, commercial or otherwise.
 *    You may modify this library or source code, and distribute it any way you
 *    like, provided the following conditions are met:
 *<br>
 *    1) You may not falsely claim to be the author of this library or any
 *    unmodified portion of it.
 *<br>
 *    2) You may not copyright this library or a modified version of it and then
 *    sue me for copyright infringement.
 *<br>
 *    3) If you modify the source code, you must clearly document the changes
 *    made before redistributing the modified source code, so other users know
 *    it is not the original code.
 *<br>
 *    4) You are not required to give me credit for this library in any derived
 *    work, but if you do, you must also mention my website:
 *    http://www.paulscode.com
 *<br>
 *    5) I the author will not be responsible for any damages (physical,
 *    financial, or otherwise) caused by the use if this library or any part
 *    of it.
 *<br>
 *    6) I the author do not guarantee, warrant, or make any representations,
 *    either expressed or implied, regarding the use of this library or any
 *    part of it.
 * <br><br>
 *    Author: Paul Lamb
 * <br>
 *    http://www.paulscode.com
 * </b>
 */
public class FilenameURL
{
	/**
	 * Processes status messages, warnings, and error messages.
	 */
	private SoundSystemLogger logger;

	/**
	 * Filename or identifier for the file.
	 */
	private String filename = null;

	/**
	 * URL interface to the file.
	 */
	private URL url = null;

	/**
	 * Constructor: Saves handles to the url and identifier.  The identifier should
	 * look like a filename, and it must have the correct extension so SoundSystem
	 * knows what format to use for the file referenced by the URL instance.
	 * @param url URL interface to a file.
	 * @param identifier Identifier (filename) for the file.
	 */
	public FilenameURL( URL url, String identifier )
	{
		// grab a handle to the message logger:
		logger = SoundSystemConfig.getLogger();

		filename = identifier;
		this.url = url;
	}

	/**
	 * Constructor: Saves a handle to the filename (used later to generate a URL
	 * instance).  The file may either be located within the
	 * JAR or at an online location.  If the file is online, filename must begin
	 * with "http://", since that is how SoundSystem recognizes URL names.
	 * @param filename Name of the file.
	 */
	public FilenameURL( String filename )
	{
		// grab a handle to the message logger:
		logger = SoundSystemConfig.getLogger();

		this.filename = filename;
		url = null;
	}

	/**
	 * Returns the filename/identifier.
	 * @return Filename or identifier for the file.
	 */
	public String getFilename()
	{
		return filename;
	}

	/**
	 * Returns the URL interface to the file.  If a URL was not originally specified
	 * in the constructor, then the first time this method is called it creates a
	 * URL instance using the previously specified filename.
	 * @return URL interface to the file.
	 */
	public URL getURL()
	{
		if( url == null )
		{
			// Check if the file is online or inside the JAR:
			if( filename.matches( SoundSystemConfig.PREFIX_URL ) )
			{
				// Online
				try
				{
					url = new URL( filename );
				}
				catch( Exception e )
				{
					errorMessage( "Unable to access online URL in " +
							"method 'getURL'" );
					printStackTrace( e );
					return null;
				}
			}
			else
			{
				// Inside the JAR
				url = getClass().getClassLoader().getResource(
						SoundSystemConfig.getSoundFilesPackage() + filename );

				if(url == null) {
					loadFromAbsolutePath();
				}
			}
		}
		return url;
	}

	private void loadFromAbsolutePath() {
		try {
			url = new URL(IOHelper.FILE_PREFIX+filename);
		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	/**
	 * Prints an error message.
	 * @param message Message to print.
	 */
	private void errorMessage( String message )
	{
		logger.errorMessage( "MidiChannel", message, 0 );
	}

	/**
	 * Prints an exception's error message followed by the stack trace.
	 * @param e Exception containing the information to print.
	 */
	private void printStackTrace( Exception e )
	{
		logger.printStackTrace( e, 1 );
	}
}