Npt.java

/*******************************************************************************
 * * This program is free software; you can redistribute it and/or modify * it
 * under the terms of the GNU General Public License as published by * the Free
 * Software Foundation; either version 2 of the License, or * (at your option)
 * any later version. * * Copyright (C) 2005 - Matteo Merli -
 * matteo.merli@gmail.com * *
 ******************************************************************************/

/*
 * $Id: Npt.java 279 2005-11-13 21:42:59Z merlimat $ $URL:
 * svn+ssh://merlimat@svn.berlios.de/svnroot/repos/rtspproxy/trunk/src/main/java/rtspproxy/lib/PortManager.java $
 */

package video.lib;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Utility class that deals with Npt timing descriptions.
 * <p>
 * A Npt time is usually represented in this form: <code>npt=0-54.23</code>
 * 
 * @author Matteo Merli
 */
public class Npt
{

	private double timeStart;
	private double timeEnd;
	private boolean live;

	private static final Pattern ntpPattern = Pattern.compile( "npt=([^-]*)-([^-]*)" );
	private static final Pattern ntpHHMMSSPattern = Pattern.compile( "npt=([0-9]+)-([^-]*)" );

	/**
	 * Construct a new Npt
	 */
	public Npt()
	{
		timeStart = 0.0;
		timeEnd = 0.0;
	}

	/**
	 * Construct a new Npt description parsing data from a String
	 * 
	 * @param ntpString the String containg the description
	 * @return a new Npt object or <code>null</code> if the description is not
	 *         valid
	 */
	public static Npt fromString( String ntpString )
	{
		Matcher m1 = ntpPattern.matcher( ntpString );
		Matcher m2 = ntpHHMMSSPattern.matcher( ntpString );
		double start = 0.0, end = 0.0;
		boolean live = false;

		if ( m1.matches() ) {
			String sStart = m1.group( 1 );
			String sEnd = m1.group( 2 );

			if ( "now".equals( sStart ) ) {
				live = true;
			} else {
				live = false;
				try {
					start = Double.parseDouble( sStart );
					if ( sEnd.length() != 0 )
						end = Double.parseDouble( sEnd );
				} catch ( NumberFormatException e ) {
					// strings format is not valid
					return null;
				}
			}
		} else
			if ( m2.matches() ) {
				
			} else {
				// Format not valid 
			}

		Npt npt = new Npt();
		npt.setTimeStart( start );
		npt.setTimeEnd( end );
		npt.setLive( live );

		return npt;
	}

	public String toString()
	{
		StringBuilder s = new StringBuilder();
		s.append( "npt=" );
		if ( live )
			s.append( "now-" );
		else {
			if ( timeStart == 0.0 )
				s.append( "0-" );
			else {
				s.append( Double.toString( timeStart ) );
				s.append( "-" );
			}

			if ( timeEnd != 0.0 ) {
				// If timeEnd is 0 we can omit it
				s.append( Double.toString( timeEnd ) );
			}
		}

		return s.toString();
	}

	/**
	 * @return Returns true if the timeing is <i>now</i> and so it represents a
	 *         live event.
	 */
	public boolean isLive()
	{
		return live;
	}

	/**
	 * @return Returns the timeEnd.
	 */
	public double getTimeEnd()
	{
		return timeEnd;
	}

	/**
	 * @param timeEnd The timeEnd to set.
	 */
	public void setTimeEnd( double timeEnd )
	{
		this.timeEnd = timeEnd;
	}

	/**
	 * @return Returns the timeStart.
	 */
	public double getTimeStart()
	{
		return timeStart;
	}

	/**
	 * @param timeStart The timeStart to set.
	 */
	public void setTimeStart( double timeStart )
	{
		this.timeStart = timeStart;
	}

	public void setLive( boolean live )
	{
		this.live = live;
	}

}