stash

Author: HarryDulaney

ch_32/Exercise32_02.java

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+package ch_32;
+
+import java.sql.*;
+
+import ch_32.common.ChartModel;
+import ch_32.common.BarChart;
+import ch_32.common.Constants;
+import ch_32.common.PieChart;
+import javafx.scene.Scene;
+import javafx.scene.layout.HBox;
+import javafx.stage.Stage;
+import javafx.application.Application;
+
+/**
+ * **32.2 (Visualize data) Write a program that displays the number of students in each
+ * department in a pie chart and a bar chart, as shown in Figure 32.27b. The number
+ * of students for each department can be obtained from the Student table (see
+ * Figure 32.4) using the following SQL statement:
+ * select deptId, count(*)
+ * from Student
+ * where deptId is not null
+ * group by deptId;
+ * <p>
+ * <p>
+ * Chapter 32 Exercises require DB setup see the ReadMe.md for detailed instructions.
+ */
+public class Exercise32_02 extends Application {
+    private String[] dataName;
+    private double[] data;
+
+    @Override
+    public void start(Stage primaryStage) {
+        initializeDB();
+
+        ChartModel chartModel = new ChartModel();
+        chartModel.setChartData(dataName, data);
+
+        PieChart pieChart = new PieChart();
+        BarChart barChart = new BarChart();
+
+        HBox hBox = new HBox(5);
+        hBox.getChildren().addAll(pieChart, barChart);
+
+        Scene scene = new Scene(hBox, 420, 80);
+        primaryStage.setTitle(getClass().getName());
+        primaryStage.setScene(scene);
+        primaryStage.show();
+
+        pieChart.setModel(chartModel);
+        barChart.setModel(chartModel);
+    }
+
+    private void initializeDB() {
+        try {
+            Connection conn = DriverManager.getConnection
+        (Constants.MY_SQL_DB_URL, Constants.MY_SQL_DB_USERNAME, Constants.MY_SQL_DB_PASSWORD);
+            System.out.println("Database connected\n");
+
+            // Connect to the sample database
+            Statement stmt = conn.createStatement();
+            ResultSet rs = stmt.executeQuery(
+                    "select deptId, count(*) from Student where deptId is not null group by deptId;");
+
+            // Count rows
+            int count = 0;
+            while (rs.next()) {
+                count++;
+            }
+
+            dataName = new String[count];
+            data = new double[count];
+
+            // We have to obtain the result set again
+            rs = stmt.executeQuery(
+                    "select deptId, count(*) from Student where deptId is not null group by deptId;");
+            int i = 0;
+            while (rs.next()) {
+                dataName[i] = rs.getString(1);
+                data[i] = rs.getInt(2);
+                i++;
+            }
+        } catch (Exception ex) {
+            System.out.println("Error: " + ex.getMessage());
+        }
+    }
+}
+

ch_32/ReadMe.md

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+# Chapter 32 - _Java Database Programming_
+### This chapter requires some additional setup because of the dependency on the MySQL database. The following steps are required to run the examples and exercises in this chapter.
+- Install Docker
+- Run the docker-compose.yml file in the ch_32 directory
+- Run the SQL script in the ch_32 directory to create the database and table
+
+### Detailed instructions on how to install Docker and set up the MySQL database can be found here:
+### [Medium Article - Install Docker and compose a MySQL db container](https://medium.com/@chrischuck35/how-to-create-a-mysql-instance-with-docker-compose-1598f3cc1bee)

ch_32/common/BarChart.java

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+package ch_32.common;
+
+import javafx.event.ActionEvent;
+import javafx.event.EventHandler;
+import javafx.scene.layout.Pane;
+import javafx.scene.paint.Color;
+import javafx.scene.shape.Line;
+import javafx.scene.shape.Rectangle;
+import javafx.scene.text.Text;
+
+public class BarChart extends Pane implements EventHandler<ActionEvent> {
+  Color[] colors = {Color.RED, Color.YELLOW, Color.GREEN, Color.BLUE,
+    Color.CYAN, Color.MAGENTA, Color.ORANGE, Color.PINK,
+    Color.GRAY};
+  private ChartModel model;
+
+  public BarChart() {
+    repaint();
+  }
+
+  double width = 200;
+  double height = 200;
+  
+  public void repaint() {
+   if (model == null) return;
+
+    String[] dataName = model.getDataName();
+    double[] data = model.getData();
+
+    // Find the maximum value in the data
+    double max = data[0];
+    for (int i=1; i<data.length; i++)
+      max = Math.max(max, data[i]);
+
+    double barWidth = (width - 10.0) / data.length - 10;
+    double maxBarHeight = height - 30;
+
+    getChildren().add(new Line(5, height - 10, width - 5, height - 10));
+
+    int x = 15;
+    for (int i = 0; i < data.length; i++) {
+      double newHeight = maxBarHeight * data[i] / max;
+      double y = height - 10 - newHeight;
+      Rectangle rectangle = new Rectangle(x, y, barWidth, newHeight);
+      rectangle.setFill(colors[i % colors.length]);
+     
+      getChildren().add(rectangle);
+      getChildren().add(new Text(x, y - 7, dataName[i]));
+      x += barWidth + 10;
+    }
+  }
+  
+  public void setModel(ChartModel newModel) {
+    model = newModel;
+    model.addActionListener(this);
+    repaint();
+  }
+
+  public ChartModel getModel() {
+    return model;
+  }
+
+  @Override
+  public void handle(ActionEvent e) {
+    repaint();
+  }
+}

ch_32/common/ChartModel.java

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+package ch_32.common;
+
+import java.util.*;
+
+import javafx.event.EventHandler;
+import javafx.event.ActionEvent;
+
+public class ChartModel {
+    private double[] data = {200, 40, 50, 100, 40, 10};
+    private String[] dataName = {"CS", "Math", "Chem", "Biol", "Phys", "Buss"};
+
+    private transient Vector<EventHandler<ActionEvent>> actionListeners;
+
+    public ChartModel() {
+    }
+
+    public double[] getData() {
+        return data;
+    }
+
+    public synchronized void removeActionListener(EventHandler<ActionEvent> l) {
+        if (actionListeners != null && actionListeners.contains(l)) {
+            Vector<EventHandler<ActionEvent>> v = (Vector<EventHandler<ActionEvent>>) actionListeners.clone();
+            v.removeElement(l);
+            actionListeners = v;
+        }
+    }
+
+    public synchronized void addActionListener(EventHandler<ActionEvent> l) {
+        Vector<EventHandler<ActionEvent>> v = actionListeners == null ? new Vector<>(2) : (Vector) actionListeners.clone();
+        if (!v.contains(l)) {
+            v.addElement(l);
+            actionListeners = v;
+        }
+    }
+
+    protected void fireActionPerformed(ActionEvent e) {
+        if (actionListeners != null) {
+            Vector<EventHandler<ActionEvent>> listeners = actionListeners;
+            int count = listeners.size();
+            for (int i = 0; i < count; i++) {
+                listeners.elementAt(i).handle(e);
+            }
+        }
+    }
+
+    public void setChartData(String[] newDataName, double[] newData) {
+        dataName = newDataName;
+        data = newData;
+        // System.arraycopy(newData, 0, data, 0, newData.length);
+        fireActionPerformed(new ActionEvent());
+    }
+
+    public String[] getDataName() {
+        return dataName;
+    }
+}
+

ch_32/common/Constants.java

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+package ch_32.common;
+
+public class Constants {
+
+    private Constants() {
+    }
+
+    public static final String MY_SQL_DB_URL = "jdbc:mysql://localhost:3306/db";
+    public static final String MY_SQL_DB_USERNAME = "user";
+    public static final String MY_SQL_DB_PASSWORD = "password";
+
+}

ch_32/common/PieChart.java

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+package ch_32.common;
+
+import javafx.event.ActionEvent;
+import javafx.event.EventHandler;
+import javafx.scene.layout.Pane;
+import javafx.scene.paint.Color;
+import javafx.scene.shape.Arc;
+import javafx.scene.shape.ArcType;
+import javafx.scene.text.Text;
+
+public class PieChart extends Pane implements EventHandler<ActionEvent> {
+    public PieChart() {
+        repaint();
+    }
+
+    private Color[] colors = {Color.RED, Color.YELLOW, Color.GREEN, Color.BLUE,
+            Color.CYAN, Color.MAGENTA, Color.ORANGE, Color.PINK,
+            Color.GRAY};
+    private ChartModel model;
+
+    double width = 200;
+    double height = 200;
+
+    private void repaint() {
+        if (model == null) return;
+
+        double radius = Math.min(width, height) * 0.5 * 0.9;
+        double x = width / 2;
+        double y = height / 2;
+
+        String[] dataName = model.getDataName();
+        double[] data = model.getData();
+
+        double total = 0;
+        for (int i = 0; i < data.length; i++) {
+            total += data[i];
+        }
+
+        double angle1 = 0;
+        double angle2 = 0;
+        for (int i = 0; i < data.length; i++) {
+            angle1 = angle1 + angle2;
+            angle2 = Math.ceil(360 * data[i] / total);
+            Arc arc = new Arc(x, y, radius, radius, angle1, angle2);
+            arc.setType(ArcType.ROUND);
+            arc.setFill(colors[i % colors.length]);
+            getChildren().add(arc);
+            getChildren().add(new Text(
+                    width / 2 + radius * Math.cos((angle1 + angle2 / 2) * 2 * Math.PI / 360),
+                    height / 2 - radius * Math.sin((angle1 + angle2 / 2) * 2 * Math.PI / 360), dataName[i]));
+        }
+    }
+
+    public void setModel(ChartModel newModel) {
+        model = newModel;
+        model.addActionListener(this);
+        repaint();
+    }
+
+    public ChartModel getModel() {
+        return model;
+    }
+
+    @Override
+    public void handle(ActionEvent e) {
+        repaint();
+    }
+}