Class ExternalEventsQueue

input/ExternalEventsQueue.java:17–163

Queue of external events. This class also takes care of buffering the events and preloading only a proper amount of them.

 * the events and preloading only a proper amount of them.
 */
public class ExternalEventsQueue implements EventQueue {
	/** ExternalEvents namespace ({@value})*/
	public static final String SETTINGS_NAMESPACE = "ExternalEvents";
	/** number of event to preload -setting id ({@value})*/
	public static final String PRELOAD_SETTING = "nrofPreload";
	/** path of external events file -setting id ({@value})*/
	public static final String PATH_SETTING = "filePath";
	
	/** default number of preloaded events */
	public static final int DEFAULT_NROF_PRELOAD = 500;
	
	private File eventsFile;
	private ExternalEventsReader reader;
	private int nextEventIndex;
	private int nrofPreload;
	private List<ExternalEvent> queue;
	private boolean allEventsRead = false;
	
	/**
	 * Creates a new Queue from a file
	 * @param filePath Path to the file where the events are read from. If
	 * file ends with extension defined in {@link BinaryEventsReader#BINARY_EXT}
	 * the file is assumed to be a binary file.
	 * @param nrofPreload How many events to preload
	 * @see BinaryEventsReader#BINARY_EXT
	 * @see BinaryEventsReader#storeToBinaryFile(String, List)
	 */
	public ExternalEventsQueue(String filePath, int nrofPreload) {
		setNrofPreload(nrofPreload);
		init(filePath);
	}
	
	/**
	 * Create a new Queue based on the given settings: {@link #PRELOAD_SETTING}
	 * and {@link #PATH_SETTING}. The path setting supports value filling.
	 * @param s The settings
	 */
	public ExternalEventsQueue(Settings s) {
		if (s.contains(PRELOAD_SETTING)) {
			setNrofPreload(s.getInt(PRELOAD_SETTING));
		}
		else {
			setNrofPreload(DEFAULT_NROF_PRELOAD);
		}
        String eeFilePath = s.valueFillString(s.getSetting(PATH_SETTING));
        init(eeFilePath);
    }

	/**
	 * Sets maximum number of events that are read when the next preload occurs
	 * @param nrof Maximum number of events to read. If less than 1, default
	 * value ( {@value DEFAULT_NROF_PRELOAD} ) is used.
	 */
	public void setNrofPreload(int nrof) {
		if (nrof < 1) {
			nrof = DEFAULT_NROF_PRELOAD;
		}
		this.nrofPreload = nrof;