return (Completed) getProperty(Property.COMPLETED);
    }

    /**
     * @return the optional creation-time property
     */
    public final Created getCreated() {
        return (Created) getProperty(Property.CREATED);
    }

    /**
     * @return the optional description property
     */
    public final Description getDescription() {
        return (Description) getProperty(Property.DESCRIPTION);
    }

    /**
     * Convenience method to pull the DTSTART out of the property list.
     * @return The DtStart object representation of the start Date
     */
    public final DtStart getStartDate() {
        return (DtStart) getProperty(Property.DTSTART);
    }

    /**
     * @return the optional geographic position property
     */
    public final Geo getGeographicPos() {
        return (Geo) getProperty(Property.GEO);
    }

    /**
     * @return the optional last-modified property
     */
    public final LastModified getLastModified() {
        return (LastModified) getProperty(Property.LAST_MODIFIED);
    }

    /**
     * @return the optional location property
     */
    public final Location getLocation() {
        return (Location) getProperty(Property.LOCATION);
    }

    /**
     * @return the optional organizer property
     */
    public final Organizer getOrganizer() {
        return (Organizer) getProperty(Property.ORGANIZER);
    }

    /**
     * @return the optional percentage complete property
     */
    public final PercentComplete getPercentComplete() {

        PropertyValidator.getInstance().assertOneOrLess(Property.PRIORITY,
                getProperties());
        PropertyValidator.getInstance().assertOneOrLess(Property.RECURRENCE_ID,
                getProperties());
        PropertyValidator.getInstance().assertOneOrLess(Property.SEQUENCE,
                getProperties());
        PropertyValidator.getInstance().assertOneOrLess(Property.STATUS,
                getProperties());
        PropertyValidator.getInstance().assertOneOrLess(Property.SUMMARY,
                getProperties());
        PropertyValidator.getInstance().assertOneOrLess(Property.UID,
                getProperties());
        PropertyValidator.getInstance().assertOneOrLess(Property.URL,
                getProperties());

        Status status = (Status) getProperty(Property.STATUS);
        if (status != null && !Status.VTODO_NEEDS_ACTION.equals(status)

        if (!CompatibilityHints
                .isHintEnabled(CompatibilityHints.KEY_RELAXED_VALIDATION)) {

            // From "4.8.4.7 Unique Identifier":
            // Conformance: The property MUST be specified in the "VEVENT", "VTODO",
            // "VJOURNAL" or "VFREEBUSY" calendar components.
            PropertyValidator.getInstance().assertOne(Property.UID,
                    getProperties());

            // From "4.8.7.2 Date/Time Stamp":
            // Conformance: This property MUST be included in the "VEVENT", "VTODO",
            // "VJOURNAL" or "VFREEBUSY" calendar components.
            PropertyValidator.getInstance().assertOne(Property.DTSTAMP,
                    getProperties());
        }

        /*
         * ; the following are optional, ; but MUST NOT occur more than once class / created / description / dtstart /
         * dtstamp / last-mod / organizer / recurid / seq / status / summary / uid / url /
         */
        PropertyValidator.getInstance().assertOneOrLess(Property.CLASS,
                getProperties());
        PropertyValidator.getInstance().assertOneOrLess(Property.CREATED,
                getProperties());
        PropertyValidator.getInstance().assertOneOrLess(Property.DESCRIPTION,
                getProperties());
        PropertyValidator.getInstance().assertOneOrLess(Property.DTSTART,
                getProperties());
        PropertyValidator.getInstance().assertOneOrLess(Property.DTSTAMP,

        return (Priority) getProperty(Property.PRIORITY);
    }

    /**
     * @return the optional date-stamp property
     */
    public final DtStamp getDateStamp() {
        return (DtStamp) getProperty(Property.DTSTAMP);
    }

    /**
     * @return the optional sequence number property
     */
    public final Sequence getSequence() {
        return (Sequence) getProperty(Property.SEQUENCE);
    }

    /**
     * @return the optional status property
     */
    public final Status getStatus() {
        return (Status) getProperty(Property.STATUS);
    }

    /**
     * @return the optional summary property
     */
    public final Summary getSummary() {
        return (Summary) getProperty(Property.SUMMARY);
    }

    /**
     * @return the optional URL property
     */
    public final Url getUrl() {
        return (Url) getProperty(Property.URL);
    }

    /**
     * @return the optional recurrence identifier property
     */
    public final RecurrenceId getRecurrenceId() {
        return (RecurrenceId) getProperty(Property.RECURRENCE_ID);
    }

    /**
     * @return the optional Duration property
     */
    public final Duration getDuration() {