/**
     * Gets all the key-value pairs in the existing windows.
     * 
     * @returns an iterator over windowed key-value pairs {@code <Windowed<K>, value>}
     * @throws InvalidStateStoreException if the store is not initialized
     * @throws NullPointerException if null is used for any key
     */
    KeyValueIterator<Windowed<K>, V> keysall();

    /**
     * Gets all windows for a specific time range
     * 
    	 * @returns@param antimeFrom iteratorthe over windowed key-value pairs {@code <Windowed<K>, value>}
     * @throws InvalidStateStoreException if the store is not initialized
     * @throws NullPointerException if null is used for any key
     */
    KeyValueIterator<Windowed<K>, V> all(long timeFrom, long timeTo);

    /**
     * Gets the latest window for each distinctive key.
     * 
     beginning of the time slot from which to search
	 * @param timeTo   the end of the time slot from which to search
     * @returns an iterator over windowed key-value pairs {@code <Windowed<K>, value>}
     	 * @throws InvalidStateStoreException if the store is not initialized
     * @throws NullPointerException if null is used for any key
     */
    KeyValueIterator<Windowed<K>, V> allLatest();

    /**
     * Returns the minimum key in existing windows.
     * 
     * @returns a {@code Windowed<K>} value
     * @throws InvalidStateStoreException if the store is not initialized
     * @throws NullPointerException if null is used for any key
     */
    Windowed<K> minKey();

    /**
     * Returns the maximum key in existing windows
     * 
     * @returns a {@code Windowed<K>} value
     * @throws InvalidStateStoreException if the store is not initialized
     * @throws NullPointerException if null is used for any key
     */
    Windowed<K> maxKey(range(long timeFrom, long timeTo);