51Degrees Device Detection Java  4.1

Device detection services for 51Degrees Pipeline


This example shows how to retrieve property meta data from 51Degrees on-premise device detection. This feature can be used to get information such as the category that a property belongs to or the possible values a property can have. (As of the current data file. If the data file is updated, the possible values for a property can change)

This example is available in full on GitHub.

This example requires a local data file. Free data files can be acquired by pulling the submodules under this repository or from the device-detection-data GitHub repository.

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package fiftyone.devicedetection.examples.hash;
import fiftyone.devicedetection.examples.ExampleBase;
import fiftyone.devicedetection.examples.ProgramBase;
import fiftyone.devicedetection.hash.engine.onpremise.flowelements.DeviceDetectionHashEngine;
import fiftyone.devicedetection.hash.engine.onpremise.flowelements.DeviceDetectionHashEngineBuilder;
import fiftyone.pipeline.engines.Constants;
import fiftyone.pipeline.engines.fiftyone.data.FiftyOneAspectPropertyMetaData;
import fiftyone.pipeline.engines.fiftyone.data.ValueMetaData;
public class MetaData extends ProgramBase {
public static void main(String[] args) throws Exception {
String dataFile = args.length > 0 ? args[0] :
new Example(true).run(dataFile);
System.out.println("Complete. Press enter to exit.");
public static class Example extends ExampleBase {
public Example(boolean printOutput) {
// truncate value if it contains newline (esp for the JavaScript property)
private String truncateToNl(String s) {
int i = s.indexOf('\n', 3);
if (i == -1) {
return s;
return s.substring(0, i + 2) + " ...";
public void run(String dataFile) throws Exception {
println("Constructing pipeline with engine " +
"from file " + dataFile);
// Build a new on-premise Hash engine with the low memory performance profile.
try (DeviceDetectionHashEngine engine =
new DeviceDetectionHashEngineBuilder()
// Prefer low memory profile where all data streamed
// from disk on-demand. Experiment with other profiles.
.build(dataFile, false)) {
// Iterate over all properties in the data file, printing the name, value type,
// and description for each one.
for (FiftyOneAspectPropertyMetaData property :
engine.getProperties()) {
printf("%s (%s) - %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() != "Device Metrics") {
StringBuilder values = new StringBuilder("Possible values: ");
int numValues = 0;
for(ValueMetaData value : property.getValues()) {
if(numValues <= 20) {
// add value
// add description if exists
if (value.getDescription().isEmpty() == false)
if (numValues > 20)
values.append(" + " + (numValues - 20) + " more ...");