Document TextArea Predicated Text Feature

[hyyan]

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import com.webforj.App;
import com.webforj.annotation.InlineStyleSheet;
import com.webforj.component.field.TextArea;
import com.webforj.component.window.Frame;
import com.webforj.exceptions.WebforjException;
import com.webforj.exceptions.WebforjRuntimeException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.List;

@InlineStyleSheet(
/* css */ """
    dwc-textarea {
      display: block;
      margin: var(--dwc-space-m) auto;
      max-width: 600px;
      height: 200px;
    }""")
public class PredictedValue extends App {
  private static final String API_URL = "https://api.datamuse.com/sug?s=";
  TextArea textArea = new TextArea("Predicted Text", "", "Type something to see suggestions");

  @Override
  public void run() throws WebforjException {
    textArea.setHelperText("Type something to see suggestions, for instance, type 'Sky is'. "
        + "Then wait for a few seconds to see the suggestions. You can insert the suggestion"
        + "by pressing Tab or ArrowRight key or simply ignore it by typing further.");
    textArea.onValueChange(event -> {
      try {
        String input = event.getValue();
        if (input.length() == 0) {
          textArea.setPredictedText("");
          return;
        }

        String bestSuggestion = fetchBestSuggestion(input);
        String predictedValue = "";
        if (!bestSuggestion.isEmpty() && bestSuggestion.length() >= input.length()) {
          predictedValue = input + bestSuggestion.substring(input.length());
        }

        textArea.setPredictedText(predictedValue);
      } catch (Exception e) {
        throw new WebforjRuntimeException("Failed to fetch suggestions", e);
      }
    });

    Frame frame = new Frame();
    frame.setTitle("Predicted Text");
    frame.add(textArea);
  }

  /**
   * Fetches the best suggestion from the API.
   *
   * @param input The input text
   * @return The best suggestion
   * @throws Exception If the API call fails
   */
  public String fetchBestSuggestion(String input) throws Exception {
    String urlString = API_URL + URLEncoder.encode(input, StandardCharsets.UTF_8.toString()) + "*";
    URL url = new URL(urlString);
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setRequestMethod("GET");

    BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
    String inputLine;
    StringBuilder content = new StringBuilder();
    while ((inputLine = in.readLine()) != null) {
      content.append(inputLine);
    }
    in.close();
    conn.disconnect();

    // Parse JSON response
    Gson gson = new Gson();
    List<WordSuggestion> suggestions =
        gson.fromJson(content.toString(), new TypeToken<List<WordSuggestion>>() {}.getType());

    // Find the word with the highest score
    WordSuggestion bestSuggestion = suggestions.stream()
        .max((a, b) -> Integer.compare(a.getScore(), b.getScore())).orElse(new WordSuggestion());

    return bestSuggestion.getWord();
  }

  /**
   * Represents a suggestion with a score.
   */
  public final class WordSuggestion {
    private String word = "";
    private int score = 0;

    public String getWord() {
      return word;
    }

    public int getScore() {
      return score;
    }
  }
}

[hyyan]

see #166