Chapter 21 Exercise 11, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

21.11 (Baby name popularity ranking)
Use the data files from Programming Exercise 12.31 to write a
program that enables the user to select a year, gender, and
enter a name to display the ranking of the name for the selected
year and gender, as shown in Figure 21.9. To achieve the best efficiency,
create two arrays for boy’s names and girl’s names, respectively. Each array
has 10 elements for 10 years. Each element is a map that stores a name and
its ranking in a pair with the name as the key. Assume the data files are
stored at www.cs.armstrong .edu/liang/data/babynamesranking2001.txt, . . . ,
and www.cs.armstrong.edu/liang/data/ babynamesranking2010.txt.

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.geometry.HPos;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.input.KeyCode;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;
import java.io.*;
import java.net.URL;
import java.util.HashMap;
import java.util.Scanner;

public class Exercise_11 extends Application {


    @Override
    public void start(Stage primaryStage) throws Exception {

        BabyNamePopulation pane = new BabyNamePopulation();
        Scene scene = new Scene(pane);
        primaryStage.setScene(scene);
        primaryStage.setTitle("Baby Name Popularity Ranking");
        primaryStage.show();

    }

    private class BabyNamePopulation extends GridPane {

        Label lblYear;
        ComboBox<String> cbYear;

        Label lblGender;
        ComboBox<String> cbGender;

        Label lblName;
        TextField tfName;

        Button btnFindRanking;

        Label lblResult;

        HashMap<String, Integer>[][] babyNamesMapArray;
        // babyNamesMapArray outer indices (e.g babyNamesMapArray[MALE][] or babyNamesMapArray[FEMALE][])
        final int MALE = 0;
        final int FEMALE = 1;

        private BabyNamePopulation() {

            // Load files and get the available years
            String[] years = loadFiles();

            // Year
            lblYear = new Label("Select Year:"); // Add years to combo box
            cbYear = new ComboBox<>(FXCollections.observableArrayList(years));
            cbYear.setValue(years[0]);

            // Gender
            lblGender = new Label("Boy or Girl?");
            cbGender = new ComboBox<>(FXCollections.observableArrayList("Boy", "Girl"));
            cbGender.setValue("Boy");

            // Name
            lblName = new Label("Enter Name:");
            tfName = new TextField();

            btnFindRanking = new Button("Find Ranking");

            lblResult = new Label("Search a name...");

            // Add nodes to grid pane
            add(lblYear, 0, 0);
            add(cbYear, 1, 0);

            add(lblGender, 0, 1);
            add(cbGender, 1, 1);

            add(lblName, 0, 2);
            add(tfName, 1, 2);

            add(btnFindRanking, 0, 3, 2, 1);

            add(lblResult, 0, 4, 2, 1);


            // Add padding and alignment to node elements
            setPadding(new Insets(10, 10, 20, 10));
            setVgap(10);
            setHgap(10);
            setHalignment(btnFindRanking, HPos.CENTER);

            // Set listeners
            btnFindRanking.setOnAction(e-> findRanking());
            tfName.setOnKeyPressed(event-> {
                if (event.getCode() == KeyCode.ENTER) findRanking();
            });

        }

        private String[] loadFiles() {

            // Get the baby name file from cs.armstrong website
            String baseURL = "http://www.cs.armstrong.edu/liang/data/babynamesranking";
            String[] urls = new String[10];
            String[] years = new String[urls.length];

            babyNamesMapArray = (HashMap<String, Integer>[][])new HashMap[2][urls.length];

            for (int j = 0; j < babyNamesMapArray.length; j++)
                for (int i = 0; i < babyNamesMapArray[j].length; i++)
                    babyNamesMapArray[j][i] = new HashMap<>();

            for (int i = 0; i < urls.length; i++) {
                years[i] = (2001 + i) + ""; // create the years array
                urls[i] = baseURL + years[i] +".txt";

                try {
                    URL url = new URL(urls[i]);
                    Scanner in = new Scanner(url.openStream());

                    int gender = 0;
                    Integer rank = 0;
                    while (in.hasNext()) {
                        if (gender == 0)
                            rank = in.nextInt();
                        String name = in.next();
                        String popularity = in.next(); // trash for now
                        babyNamesMapArray[gender][i].put(name, rank);

                        if (gender == 1)
                            gender = 0;
                        else
                            gender++;
                    }

                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            return years;
        }

        private void findRanking() {
            String name = tfName.getText();
            if (name.length() == 0) {
                lblResult.setText("Please enter a valid name...");
                return;
            }
            String yearString = cbYear.getValue();
            int year = Integer.parseInt(yearString.substring(2)) - 1;
            System.out.println(year);
            String genderString = cbGender.getValue();
            int gender = (genderString.equals("Boy")) ? MALE : FEMALE;

            String formatName = Character.toUpperCase(name.charAt(0)) + name.substring(1).toLowerCase();
            if (babyNamesMapArray[gender][year].containsKey(formatName)) {
                Integer rank = babyNamesMapArray[gender][year].get(formatName);
                lblResult.setText(genderString + " name " + formatName +
                        " is ranked #" + rank + "\n in year " + yearString);
            } else {
                lblResult.setText("Sorry, No name was matched.\nMaybe no one likes that name?");
            }

        }
    }

}