Java Client for Google Maps Services

Description

Use Java? Want to geocode something? Looking for directions?
Maybe matrices of directions? This library brings the Google Maps API Web
Services to your server-side Java application.

The Java Client for Google Maps Services is a Java Client library for the following Google Maps
APIs:

• Directions API
• Distance Matrix API
• Elevation API
• Geocoding API
• Maps Static API
• Places API
• Roads API
• Time Zone API

Keep in mind that the same terms and conditions apply
to usage of the APIs when they're accessed through this library.

Intended usage of this library

The Java Client for Google Maps Services is designed for use in server applications. This library
is not intended for use inside of an Android app, due to the potential for loss of API keys.

If you are building a mobile application, you will need to introduce a proxy server to act as
intermediary between your mobile application and the Google Maps API Web Services. The Java
Client for Google Maps Services would make an excellent choice as the basis for such a proxy server.

Please see Making the most of the Google Maps Web Service APIs for more detail.

Looking for our Android Maps or
Places SDKs?

Support

This library is community supported. We're comfortable enough with the stability and features of
the library that we want you to build real production applications on it. We will try to support,
through Stack Overflow, the public and protected surface of the library and maintain backwards
compatibility in the future; however, while the library is in version 0.x, we reserve the right
to make backwards-incompatible changes. If we do remove some functionality (typically because
better functionality exists or if the feature proved infeasible), our intention is to deprecate
and give developers a year to update their code.

If you find a bug, or have a feature suggestion, please log an issue. If you'd like to
contribute, please read How to Contribute.

Requirements

• Java 1.8 or later.
• A Google Maps API key.

API keys

Each Google Maps Web Service request requires an API key. API keys are generated in the 'Credentials' page of the 'APIs & Services' tab of Google Cloud console.

For even more information on getting started with Google Maps Platform and generating/restricting an API key, see Get Started with Google Maps Platform in our docs.

Important: This key should be kept secret on your server.

Installation

You can add the library to your project via Maven or Gradle.

Note: Since 0.1.18 there is now a dependency on SLF4J. You need to add
one of the adapter dependencies that makes sense for your logging setup. In the configuration
samples below we are integrating
slf4j-nop,
but there are others like
slf4j-log4j12
and slf4j-jdk14
that will make more sense in other configurations. This will stop a warning message being emitted
when you start using google-maps-services.

Maven

<dependency>
  <groupId>com.google.maps</groupId>
  <artifactId>google-maps-services</artifactId>
  <version>(insert latest version)</version>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-simple</artifactId>
  <version>1.7.25</version>
</dependency>

Gradle

repositories {
    mavenCentral()
}

dependencies {
    implementation 'com.google.maps:google-maps-services:(insert latest version)'
    implementation 'org.slf4j:slf4j-simple:1.7.25'
}

You can find the latest version at the top of this README or by searching
Maven Central or Gradle, Please.

Developer Documentation

View the javadoc.

Additional documentation for the included web services is available at
https://developers.google.com/maps/.

• Directions API
• Distance Matrix API
• Elevation API
• Geocoding API
• Maps Static API
• Places API
• Roads API
• Time Zone API

Usage

This example uses the Geocoding API with an API key:

GeoApiContext context = new GeoApiContext.Builder()
    .apiKey("AIza...")
    .build();
GeocodingResult[] results =  GeocodingApi.geocode(context,
    "1600 Amphitheatre Parkway Mountain View, CA 94043").await();
Gson gson = new GsonBuilder().setPrettyPrinting().create();
System.out.println(gson.toJson(results[0].addressComponents));

The GeoApiContext is designed to be a Singleton
in your application. Please instantiate one on application startup, and continue to use it for the
life of your application. This will enable proper QPS enforcement across all of your requests.

At the end of the execution, call the shutdown() method of GeoApiContext,
otherwise the thread will remain instantiated in memory.

For more usage examples, check out the tests.

Features

Google App Engine Support

You can use this client library on Google App Engine with a single code change.

new GeoApiContext.Builder(new GaeRequestHandler.Builder())
    .apiKey("AIza...")
    .build();

The new GaeRequestHandler.Builder() argument to GeoApiContext.Builder's requestHandlerBuilder
tells the Java Client for Google Maps Services to utilise the appropriate calls for making HTTP
requests from Google App Engine, instead of the default OkHttp3
based strategy.

Rate Limiting

Never sleep between requests again! By default, requests are sent at the expected rate limits for
each web service, typically 50 queries per second for free users. If you want to speed up or slow
down requests, you can do that too, using new GeoApiContext.Builder().queryRateLimit(qps).build().
Note that you still need to manually handle the delay between the initial request and successive pages when you're paging through multiple result sets.

Retry on Failure

Automatically retry when intermittent failures occur. That is, when any of the retriable 5xx errors
are returned from the API.

To alter or disable automatic retries, see these methods in GeoApiContext:

• .disableRetries()
• .maxRetries()
• .retryTimeout()
• .setIfExceptionIsAllowedToRetry()

POJOs

Native objects for each of the API responses.

Asynchronous or synchronous -- you choose

All requests support synchronous or asynchronous calling style.

GeocodingApiRequest req = GeocodingApi.newRequest(context).address("Sydney");

// Synchronous
try {
    req.await();
    // Handle successful request.
} catch (Exception e) {
    // Handle error
}

req.awaitIgnoreError(); // No checked exception.

// Async
req.setCallback(new PendingResult.Callback<GeocodingResult[]>() {
  @Override
  public void onResult(GeocodingResult[] result) {
    // Handle successful request.
  }

  @Override
  public void onFailure(Throwable e) {
    // Handle error.
  }
});

Building the Project

Note: You will need an API key or Client ID to run the tests.

# Compile and package the project
$ ./gradlew jar

# Run the tests
$ ./gradlew test