51Degrees Device Detection Java  4.4

Device detection services for 51Degrees Pipeline


The device detection data file contains meta data that can provide additional information about the various records in the data model. This example shows how to access this data and display the values available.

To help navigate the data, it's useful to have an understanding of the types of records that are present:

  • Component - A record relating to a major aspect of the entity making a web request. There are currently 4 components: Hardware, Software Platform (OS), Browser and Crawler.
  • Profile - A record containing the details for a specific instance of a component. An example of a hardware profile would be the profile for the iPhone 13. An example of a platform profile would be Android 12.1.0.
  • Property - Each property will have a specific value (or values) for each profile. An example of a hardware property is 'IsMobile'. An example of a browser property is 'BrowserName'.

The example will output each component in turn, with a list of the properties associated with each component. Some of the possible values for each property are also displayed. There are too many profiles to display, so we just list the number of profiles for each component.

Finally, the evidence keys that are accepted by device detection are listed. These are the keys that, when added to the evidence collection in flow data, could have some impact on the result returned by device detection.

This example is available in full on GitHub.

This example requires a local data file. The free 'Lite' data file can be acquired by pulling the git submodules under this repository (run `git submodule update --recursive`) or from the device-detection-data GitHub repository.

The Lite data file is only used for illustration, and has limited accuracy and capabilities. Find out about the more capable data files that are available on our pricing page

* This Original Work is copyright of 51 Degrees Mobile Experts Limited.
* Copyright 2022 51 Degrees Mobile Experts Limited, Davidson House,
* Forbury Square, Reading, Berkshire, United Kingdom RG1 3EU.
* This Original Work is licensed under the European Union Public Licence
* (EUPL) v.1.2 and is subject to its terms as set out below.
* If a copy of the EUPL was not distributed with this file, You can obtain
* one at https://opensource.org/licenses/EUPL-1.2.
* The 'Compatible Licences' set out in the Appendix to the EUPL (as may be
* amended by the European Commission) shall be deemed incompatible for
* the purposes of the Work and the provisions of the compatibility
* clause in Article 5 of the EUPL shall not apply.
* If using the Work as, or as part of, a network application, by
* including the attribution notice(s) required under Article 5 of the EUPL
* in the end user terms of the application under an appropriate heading,
* such notice(s) shall fulfill the requirements of that article.
package fiftyone.devicedetection.examples.console;
import fiftyone.devicedetection.examples.shared.DataFileHelper;
import fiftyone.devicedetection.hash.engine.onpremise.flowelements.DeviceDetectionHashEngine;
import fiftyone.devicedetection.hash.engine.onpremise.flowelements.DeviceDetectionHashEngineBuilder;
import fiftyone.pipeline.core.data.EvidenceKeyFilterWhitelist;
import fiftyone.pipeline.engines.Constants;
import fiftyone.pipeline.engines.fiftyone.data.ComponentMetaData;
import fiftyone.pipeline.engines.fiftyone.data.ProfileMetaData;
import fiftyone.pipeline.engines.fiftyone.data.ValueMetaData;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;
import static fiftyone.common.testhelpers.LogbackHelper.configureLogback;
import static fiftyone.pipeline.util.FileFinder.getFilePath;
public class MetadataOnPrem {
private static final Logger logger = LoggerFactory.getLogger(GettingStartedOnPrem.class);
/* In this example, by default, the 51degrees "Lite" file needs to be somewhere in the project
space, or you may specify another file as a command line parameter.
Note that the Lite data file is only used for illustration, and has limited accuracy and
capabilities. Find out about the Enterprise data file here: https://51degrees.com/pricing */
public static String LITE_V_4_1_HASH = "51Degrees-LiteV4.1.hash";
public static void main(String[] args) throws Exception {
String dataFile = args.length > 0 ? args[0] : LITE_V_4_1_HASH;
run(dataFile, System.out);
public static void run(String dataFile, OutputStream output) throws Exception {
logger.info("Running MetadataOnPrem example");
String dataFileLocation;
try {
dataFileLocation = getFilePath(dataFile).getAbsolutePath();
} catch (Exception e) {
throw e;
// Build a new on-premise Hash engine with the low memory performance profile.
// Note that there is no need to construct a complete pipeline in order to access
// the meta-data.
// If you already have a pipeline and just want to get a reference to the engine
// then you can use `var engine = pipeline.GetElement<DeviceDetectionHashEngine>();`
try (DeviceDetectionHashEngine ddEngine =
new DeviceDetectionHashEngineBuilder(LoggerFactory.getILoggerFactory())
// We use the low memory profile as its performance is sufficient for this
// example. See the documentation for more detail on this and other
// configuration options:
// http://51degrees.com/documentation/_device_detection__features__performance_options.html
// http://51degrees.com/documentation/_features__automatic_datafile_updates.html
// inhibit auto-update of the data file for this test
.build(dataFileLocation, false)){
PrintWriter writer = new PrintWriter(output);
logger.info("Listing Components");
outputComponents(ddEngine, writer);
logger.info("Listing Profile Details");
outputProfileDetails(ddEngine, writer);
logger.info("Listing Evidence Key Details");
outputEvidenceKeyDetails(ddEngine, writer);
private static void outputEvidenceKeyDetails(DeviceDetectionHashEngine ddEngine,
PrintWriter output){
if (ddEngine.getEvidenceKeyFilter() instanceof EvidenceKeyFilterWhitelist) {
// If the evidence key filter extends EvidenceKeyFilterWhitelist then we can
// display a list of accepted keys.
EvidenceKeyFilterWhitelist filter = (EvidenceKeyFilterWhitelist) ddEngine.getEvidenceKeyFilter();
output.println("Accepted evidence keys:");
for (Map.Entry<String, Integer> entry : filter.getWhitelist().entrySet()){
output.println("\t" + entry.getKey());
} else {
output.format("The evidence key filter has type " +
"%s. As this does not extend " +
"EvidenceKeyFilterWhitelist, a list of accepted values cannot be " +
"displayed. As an alternative, you can pass evidence keys to " +
"filter.include(string) to see if a particular key will be included " +
"or not.\n", ddEngine.getEvidenceKeyFilter().getClass().getName());
output.println("For example, header.user-agent " +
(ddEngine.getEvidenceKeyFilter().include("header.user-agent") ?
"is " : "is not ") + "accepted.");
private static void outputProfileDetails(DeviceDetectionHashEngine ddEngine,
PrintWriter output) {
// Group the profiles by component and then output the number of profiles
// for each component.
Map<String, List<ProfileMetaData>> groups =
StreamSupport.stream(ddEngine.getProfiles().spliterator(), false)
.collect(Collectors.groupingBy(p -> p.getComponent().getName()));
groups.forEach((k,v)->output.format("%s Profiles: %d\n", k , v.size()));
// Output the component name as well as a list of all the associated properties.
// If we're outputting to console then we also add some formatting to make it
// more readable.
private static void outputComponents(DeviceDetectionHashEngine ddEngine, PrintWriter output){
ddEngine.getComponents().forEach(c -> {
output.println("Component - "+ c.getName());
outputProperties(c, output);
private static void outputProperties(ComponentMetaData component, PrintWriter output) {
if (component.getProperties().iterator().hasNext() == false) {
output.println(" ... no properties");
.forEach(property-> {
// Output some details about the property.
// If we're outputting to console then we also add some formatting to make it
// more readable.
output.format(" Property - %s [Category: %s] (%s)\n " +
"Description: %s\n",
// Next, output a list of the possible values this property can have.
// Most properties in the Device Metrics category do not have defined
// values so exclude them.
if (property.getCategory().equals("Device Metrics")==false) {
StringBuilder values = new StringBuilder(" Possible " +
"values: ");
Spliterator<ValueMetaData> spliterator2 =
StreamSupport.stream(spliterator2, false)
.forEach(value -> {
// add value
// add description if exists
String d = value.getDescription();
if (Objects.nonNull(d) && d.isEmpty() == false) {
if (spliterator2.estimateSize() > 20) {
values.append(" + more ...");
// Truncate value if it contains newline (esp for the JavaScript property)
private static String truncateToNl(String text) {
String[] lines = text.split("\n");
Optional<String> result = Arrays.stream(lines).filter(s -> !s.isEmpty()).findFirst();
return result.orElse("[empty]") + (lines.length > 1 ? "..." : "");