UpToDateChecker

UpToDateChecker is a small and basic library for checking if something is up-to-date or not.

Include in your build

Gradle

repositories {
    // ...
    mavenCentral()
}

dependencies {
    implementation 'io.github.gonalez.uptodatechecker:uptodatechecker:0.0.2'
}

Maven

<dependency>
   <groupId>io.github.gonalez.uptodatechecker</groupId>
   <artifactId>uptodatechecker</artifactId>
   <version>0.0.2</version>
</dependency>

Creating a UpToDateChecker

The first step to make use of the API is to create an instance of the UpToDateChecker, this is the entry point of the library.

UpToDateChecker upToDateChecker = UpToDateCheckerBuilder.newBuilder()
    .setExecutor(MoreExecutors.directExecutor())
    .setVersionMatchStrategy(String::equals)
    .build();

Update Downloading

One of the best features of the API is the ability to download updates when a request is not up-to-date, this can be done by setting an UpdateDownloader to the UpToDateChecker, you can use the setOptionalUpdateDownloader method for this.

The library provides a default implementation of the UpdateDownloader called FileUpdateDownloader, where the updates will be automatically downloaded to the request path.

new FileUpdateDownloader(executor, httpClient, options);

Register a Version Provider

The API provides a method called addVersionProvider, this can be used to register a version provider into the UpToDateChecker. A version provider is responsible for obtaining the latest version of something i.e. a GitHub repository, for the request context.

upToDateChecker.addVersionProvider(new GithubVersionProvider(executor, httpClient));

Creating the request

To check for up-to-date something, you first must create an CheckUpToDateRequest instance. We determine if the version is up-to-date by applying the versionMatchStrategy to the currentVersion of the request to the latest version of the VersionProvider.

There must be a version provider registered for the given request context type, otherwise the API won't know what version we're trying to compare against the request, current version.

CheckUpToDateRequest request = CheckUpToDateRequest.newBuilder()
       .setContext(
           GithubVersionProviderContext.newBuilder()
             .setRepoName("uptodatechecker")
             .setRepoOwner("gonalez")
             .build())
       .setCurrentVersion("0.0.2")
       .build();

Callback

You can also set a callback to the request to listen when we get the latest version or if there are any errors, etc.

request.setOptionalCallback(Optional.of(new UpToDateChecker.Callback() {
      @Override
      public void onUpToDate(CheckUpToDateResponse response) {
          // called if the response is up-to-date
      }

      @Override
      public void onNotUpToDate(CheckUpToDateResponse response) {
          // called if the response is not up-to-date
      }
}));

Send the request

Finally, you can send the request to check if the request is up-to-date.

ListenableFuture<CheckUpToDateResponse> response = 
    upToDateChecker.checkWithDownloadingAndScheduling()
        .requesting(request)
        .response();
assertTrue(response.isUpToDate());

Operation Chaining

You can combine several operations to be executed when checking for up-to-date something by using the ThenOperation. This example uses the download operation to download the update if the request is not up-to-date (for this to work you must register an UpdateDownloader as explained in the Update Downloading section):

upToDateChecker.checkWithDownloadingAndScheduling()
    .requesting(request)
    .then()
    .download(downloadRequest)
    // ...
    .response();

License

Licensed under the Apache License, Version 2.0: http://www.apache.org/licenses/LICENSE-2.0