Monday, July 20, 2015

JavaFX BarChart example: plot data population in histogram

Example to plot data population in histogram using JavaFX BarChart.


package javafx_histogram;

import java.util.Random;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.chart.BarChart;
import javafx.scene.chart.CategoryAxis;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

/**
 * @web http://java-buddy.blogspot.com
 */
public class JavaFX_Histogram extends Application {
    
    int DATA_SIZE = 1000;
    int data[] = new int[DATA_SIZE];
    int group[] = new int[10];
    
    @Override
    public void start(Stage primaryStage) {
        
        prepareData();
        groupData();
        
        Label labelInfo = new Label();
        labelInfo.setText(
            "java.version: " + System.getProperty("java.version") + "\n" +
            "javafx.runtime.version: " + System.getProperty("javafx.runtime.version")
        );
        
        final CategoryAxis xAxis = new CategoryAxis();
        final NumberAxis yAxis = new NumberAxis();
        final BarChart<String,Number> barChart = 
            new BarChart<>(xAxis,yAxis);
        barChart.setCategoryGap(0);
        barChart.setBarGap(0);
        
        xAxis.setLabel("Range");       
        yAxis.setLabel("Population");
        
        XYChart.Series series1 = new XYChart.Series();
        series1.setName("Histogram");       
        series1.getData().add(new XYChart.Data("0-10", group[0]));
        series1.getData().add(new XYChart.Data("10-20", group[1]));
        series1.getData().add(new XYChart.Data("20-30", group[2]));
        series1.getData().add(new XYChart.Data("30-40", group[3]));
        series1.getData().add(new XYChart.Data("40-50", group[4])); 
        
        series1.getData().add(new XYChart.Data("50-60", group[5]));
        series1.getData().add(new XYChart.Data("60-70", group[6]));
        series1.getData().add(new XYChart.Data("70-80", group[7]));
        series1.getData().add(new XYChart.Data("80-90", group[8]));
        series1.getData().add(new XYChart.Data("90-100", group[9]));
        
        barChart.getData().addAll(series1);
        
        VBox vBox = new VBox();
        vBox.getChildren().addAll(labelInfo, barChart);
        
        StackPane root = new StackPane();
        root.getChildren().add(vBox);
        
        Scene scene = new Scene(root, 800, 450);
        
        primaryStage.setTitle("java-buddy.blogspot.com");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
    
    //generate dummy random data
    private void prepareData(){

        Random random = new Random();
        for(int i=0; i<DATA_SIZE; i++){
            data[i] = random.nextInt(100);
        }
    }
    
    //count data population in groups
    private void groupData(){
        for(int i=0; i<10; i++){
            group[i]=0;
        }
        for(int i=0; i<DATA_SIZE; i++){
            if(data[i]<=10){
                group[0]++;
            }else if(data[i]<=20){
                group[1]++;
            }else if(data[i]<=30){
                group[2]++;
            }else if(data[i]<=40){
                group[3]++;
            }else if(data[i]<=50){
                group[4]++;
            }else if(data[i]<=60){
                group[5]++;
            }else if(data[i]<=70){
                group[6]++;
            }else if(data[i]<=80){
                group[7]++;
            }else if(data[i]<=90){
                group[8]++;
            }else if(data[i]<=100){
                group[9]++;
            }
        }
    }
    
}

3 comments:

  1. How would you do it if you had more than 100? Lets say the max has is 1000. What be less time consuming than if statements?

    ReplyDelete
    Replies
    1. how about something like this:
      group[(int)(data[i]/10)]++

      Delete
    2. Does that go into a for loop?

      Delete