// Device detection provider which takes User-Agents and returns matches.
    protected final Provider provider;
    
    // User-Agent string of a iPhone mobile device.
    protected final String mobileUserAgent = "Mozilla/5.0 (iPhone; CPU iPhone "
            + "OS 7_1 like Mac OS X) AppleWebKit/537.51.2 (KHTML, like Gecko) "
            + "Version/7.0 Mobile/11D167 Safari/9537.53";
    
    /**
     * Creates new provider object with the Stream dataset.
     * @throws IOException if there was a problem accessing the data file.
     */
    public MatchForDeviceId() throws IOException {
        provider = new Provider(StreamFactory.create(
                Shared.getLitePatternV32(), false));
    }
    
    /**
     * Performs a match of the pre-defined User-Agent to retrieve Id, then 
     * shows how to use the Id to get a Match object. The Id can be stored as a 
     * byte array, string or a list of integers corresponding to profiles.
     * <p>
     * Three match objects with different references but same deviceId and 
     * IsMobile values are generated to demonstrate that all three methods of 
     * storing deviceId produce the same result.
     * @param args command line arguments.
     * @throws IOException if there was a problem accessing data file.
     */
    public static void main(String[] args) throws IOException {
        MatchForDeviceId device = new MatchForDeviceId();
        // Get deviceId for some User-Agent.
        Match matchFromUA = device.matchForUserAgent(device.mobileUserAgent);
        // Store for future use.
        String deviceIdString = matchFromUA.getDeviceId();
        byte[] deviceIdByteArray = matchFromUA.getDeviceIdAsByteArray();
        ArrayList<Integer> deviceIdList = new ArrayList<Integer>();
        for (Profile profile : matchFromUA.getProfiles()) {
            deviceIdList.add(profile.profileId);
        }
        // Some time has passed. Get match for each of the storage methods.
        Match matchFromByteArray = device.matchForDeviceIdArray(deviceIdByteArray);
        Match matchFromIdString = device.matchForDeviceIdString(deviceIdString);
        Match matchFromIdList = device.matchForDeviceIdList(deviceIdList);
        
        System.out.println("Match object: " +
                System.identityHashCode(matchFromByteArray) + 
                " created from deviceId as byte array. " + 
                "deviceId: " + matchFromByteArray.getDeviceId() + 
                "IsMobile: " + matchFromByteArray.getValues("IsMobile"));
        
        System.out.println("Match object: " +
                System.identityHashCode(matchFromIdString) + 
                " created from deviceId as string. " + 
                "deviceId: " + matchFromIdString.getDeviceId() + 
                " IsMobile: " + matchFromIdString.getValues("IsMobile"));
        
        System.out.println("Match object: " +
                System.identityHashCode(matchFromIdList) + 
                " created from deviceId as list of profile Ids. " + 
                "deviceId: " + matchFromIdList.getDeviceId() + 
                "IsMobile: " + matchFromIdList.getValues("IsMobile"));
    }
    
    /**
     * Performs match for a User-Agent string and returns Match object with 
     * detection results.
     * 
     * @param userAgent String representing typical HTTP User-Agent header.
     * @return Match object with detection results.
     * @throws IOException if there was a problem accessing the data file.
     */
    public Match matchForUserAgent(String userAgent) throws IOException {
        return provider.match(mobileUserAgent);
    }
    
    /**
     * Returns a Match object corresponding to the provided string deviceId.
     * String deviceId derived by: <code>match.getDeviceId();</code>
     * 
     * @param deviceId String representation of the deviceId.
     * @return Match object with detection results.
     * @throws IOException if there was a problem accessing the data file.
     */
    public Match matchForDeviceIdString(String deviceId) throws IOException {
        return provider.matchForDeviceId(deviceId);
    }
    
    /**
     * Returns a Match object corresponding to the provided byte array Id. 
     * Byte array id is retrieved by: 
     * <code>match.getDeviceIdAsByteArray();</code>
     * 
     * @param deviceId byte array representation of deviceId.
     * @return Match object with detection results.
     * @throws IOException if there was a problem accessing the data file.
     */
    public Match matchForDeviceIdArray(byte[] deviceId) throws IOException {
        return provider.matchForDeviceId(deviceId);
    }
    
    /**
     * Returns a Match object corresponding to the provided list of profile IDs.
     * A list of profile IDs is derived from: 
     * <code>for (Profile profile : match.getProfiles()) {</code>
     * 
     * @param deviceIds a list of integers where each integer is a profile Id.
     * @return Match object with detection results.
     * @throws IOException if there was a problem accessing the data file.
     */
    public Match matchForDeviceIdList(ArrayList<Integer> deviceIds) 
                                                            throws IOException {
        return provider.matchForDeviceId(deviceIds);
    }
    
    /**
     * Closes the {@link fiftyone.mobile.detection.Dataset} by releasing data 
     * file readers and freeing the data file from locks. This method should 
     * only be used when the {@code Dataset} is no longer required, i.e. when 
     * device detection functionality is no longer required, or the data file 
     * needs to be freed.
     * 
     * @throws IOException if there is a problem accessing the data file.
     */
    public void close() throws IOException {
        provider.dataSet.close();
    }