[utopian.java v0.3.1] - Support for api key, mapping new json fields to java

Overview

Recently utopian-io added API usage limit this release added support for api key, java types has been updated to reflect new changes made to json and plus some other code improvements.

For more information on previous versions

• version 0.1.0
• version 0.2.0
• version 0.3.0

Requirements

• Java 8

utopian.java API uses features of java 8 such as lambda expressions, Subset of Java 8 features has been used in this library so that it can run on older android devices and latest ones as well as desktop Java.

Code Commits

• f21b80b

Recently utopian-io added API usage limit to the system here is the link of the post

In order to use utopian-java library now you will require API key which you can request from here. This commit added support for API key feature added to system. Once you get your API key then you just have to do these steps

System.setProperty("API_KEY", "your-key");
System.setProperty("API_KEY_ID", "your-key-id");

UtopianService service = new DefaultUtopianService();

• 599c122

In this commit some redundant code has been removed to make code simpler.

• 6353a9c

utopian-io added some new fields in Post JSON and since utopian-java library has Java type mapping for JSON, so in this commit Java Post class has been updated to reflect new changes.

• 9ac8db0

In Post JSON, inside json_metadata there is a field questions sometimes it has type JSON object and sometimes it has type JSON array so it was creating issue. In this commit i added custom json deserializer to check the type and parse according to type.

Post post = service
        .post("kabooom", "utopian-java-v0-1-0-utopian-api-for-java-and-android")
        .asJavaType()
        .get();

//if questions type is JSON Object
System.out.println(post.getJsonMetadata().getQuestionsObject());

//if questions type is JSON Array
System.out.println(post.getJsonMetadata().getQuestionsArray());

Using utopian-java in android project

In this simple tutorial we will use utopian-java in android project. We will target subset of java 8 features that can run on all android API levels.

Requirements

• Android Studio 3.0 or higher

1. Creating Android Studio project

Create new android project and change Application name you can also change Company domain and Package name according to requirements and click next

Select minimum SDK version and click next

Select Empty Activity and click next

Change Activity Name and Layout Name according to requirements and click Finish to create project

Now we will add support for Java 8 click on File menu and then click on Project Structure and then select Source Compatibility and Target Compatibility to 1.8

Now we will add utopian-java library to our project for this open build.gradle and add this line

dependencies {
    implementation 'io.faob:utopian-java:0.3.1'
   ...
   ...
}

Since our app will use internet so lets add Internet permission in AndroidManifest.xml file

<uses-permission android:name="android.permission.INTERNET"/>

2. Using Java 8 lambda expressions

In our simple app we will just get 50 latest posts and show in text view we will use getAsync() to get posts in background thread and update textview in lambda expression. Here is the complete code and output

public class MainActivity extends AppCompatActivity {
    private String titles;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        System.setProperty("API_KEY", "your-key");
        System.setProperty("API_KEY_ID", "your-key-id");
        UtopianService service = new DefaultUtopianService();

        service.posts(new HashMap<>())
                .asJavaListType() // get posts as java type
                .getAsync(posts -> { // success handler with List<Post>
                    for (Post post : posts) {
                        titles += post.getTitle() + "\n\n";

                    }
                    //its background thread so update textview on UI thread
                    runOnUiThread(() -> {
                        TextView textView = findViewById(R.id.textView);
                        textView.setText(titles);
                    });

                }, e -> { // error handler to handle exceptions
                    e.printStackTrace();
                });
    }
}

3. Using Java 8 method references

If the code is big in lambda expression then code become very ugly and difficult to maintain to solve this problem we can use method reference. Here is complete code and output

public class MainActivity extends AppCompatActivity {
    private String titles;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        System.setProperty("API_KEY", "your-key");
        System.setProperty("API_KEY_ID", "your-key-id");
        UtopianService service = new DefaultUtopianService();

        service.posts(new HashMap<>())
                .asJavaListType() // get posts as java type
                .getAsync(
                        //handle success in this method reference
                        this::handleResponse,
                        //handle exception in this method reference
                        this::handleError);
    }

    //success handler
    private void handleResponse(List<Post> posts) {
        for (Post post : posts) {
            titles += post.getTitle() + "\n\n";

        }
         //its background thread so update textview on UI thread
        runOnUiThread(() -> {
            TextView textView = findViewById(R.id.textView);
            textView.setText(titles);
        });
    }

    //exception handler
    private void handleError(Exception e) {
        e.printStackTrace();
    }
}

Contribution

Contributions are always welcome, contribution to this project is simple create fork add new features or bug fixes and send a pull request.

Download

Maven:

<repositories>
    <repository>
        <id>jcenter</id>
        <url>https://jcenter.bintray.com/</url>
    </repository>
</repositories>

<dependencies>
    <dependency>
        <groupId>io.faob</groupId>
        <artifactId>utopian-java</artifactId>
        <version>0.3.1</version>
    </dependency>
</dependencies>

Gradle:

repositories {
    jcenter()
}

dependencies {
    compile 'io.faob:utopian-java:0.3.1'
}

Github

Code

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Posted on Utopian.io - Rewarding Open Source Contributors

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