adopt MVC pattern and add real time graph interface

src/main/java/core/gui/LearningInfoPanel.java

@@ -0,0 +1,41 @@
+package core.gui;
+
+import core.algo.Learning;
+import core.controller.ViewListener;
+
+import javax.swing.*;
+
+public class LearningInfoPanel extends JPanel {
+    private Learning learning;
+    private JLabel policyLabel;
+    private JLabel discountLabel;
+    private JLabel epsilonLabel;
+    private JSlider epsilonSlider;
+    private JSlider delaySlider;
+
+    public LearningInfoPanel(Learning learning, ViewListener viewListener){
+        this.learning = learning;
+        setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
+        policyLabel = new JLabel();
+        discountLabel = new JLabel();
+        epsilonLabel = new JLabel();
+        epsilonSlider = new JSlider(0, 100, (int)(learning.getEpsilon() * 100));
+        epsilonSlider.addChangeListener(e -> viewListener.onEpsilonChange(epsilonSlider.getValue() / 100f));
+        add(policyLabel);
+        add(discountLabel);
+        add(epsilonLabel);
+        add(epsilonSlider);
+        refreshLabels();
+        setVisible(true);
+    }
+
+    public void refreshLabels(){
+        policyLabel.setText("Policy: " + learning.getPolicy().getClass());
+        discountLabel.setText("Discount factor: " + learning.getDiscountFactor());
+        epsilonLabel.setText("Exploration (Epsilon): " + learning.getEpsilon());
+    }
+
+    protected JSlider getEpsilonSlider(){
+        return epsilonSlider;
+    }
+}

src/main/java/core/gui/View.java

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+package core.gui;
+
+import core.algo.Learning;
+import core.controller.ViewListener;
+import core.listener.LearningListener;
+import lombok.Getter;
+import org.knowm.xchart.QuickChart;
+import org.knowm.xchart.XChartPanel;
+import org.knowm.xchart.XYChart;
+
+import javax.swing.*;
+import java.awt.*;
+import java.util.ArrayList;
+import java.util.List;
+
+public class View<A extends Enum> implements LearningListener {
+    private Learning<A> learning;
+    @Getter
+    private XYChart chart;
+    @Getter
+    private LearningInfoPanel learningInfoPanel;
+    @Getter
+    private JFrame mainFrame;
+    private XChartPanel<XYChart> rewardChartPanel;
+    private ViewListener viewListener;
+    private List<Double> rewardHistory;
+
+    public View(Learning<A> learning, ViewListener viewListener){
+        this.learning = learning;
+        this.viewListener = viewListener;
+        rewardHistory = new ArrayList<>();
+        this.initMainFrame();
+    }
+
+    private void initMainFrame(){
+        mainFrame = new JFrame();
+        mainFrame.setPreferredSize(new Dimension(1280, 720));
+        mainFrame.setLayout(new BorderLayout());
+
+        initLearningInfoPanel();
+        initRewardChart();
+
+        mainFrame.add(BorderLayout.WEST, learningInfoPanel);
+        mainFrame.add(BorderLayout.CENTER, rewardChartPanel);
+
+        mainFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
+        mainFrame.pack();
+        mainFrame.setVisible(true);
+    }
+
+    private void initLearningInfoPanel(){
+        learningInfoPanel = new LearningInfoPanel(learning, viewListener);
+    }
+
+    private void initRewardChart(){
+        chart =
+                QuickChart.getChart(
+                        "Rewards per Episode",
+                        "Episode",
+                        "Reward",
+                        "randomWalk",
+                        new double[] {0},
+                        new double[] {0});
+        chart.getStyler().setLegendVisible(true);
+        chart.getStyler().setXAxisTicksVisible(true);
+        rewardChartPanel = new XChartPanel<>(chart);
+        rewardChartPanel.setPreferredSize(new Dimension(300,300));
+    }
+
+    public void showState(Visualizable state){
+        new JFrame(){
+            {
+                JComponent stateComponent = state.visualize();
+                setPreferredSize(new Dimension(stateComponent.getWidth(), stateComponent.getHeight()));
+                add(stateComponent);
+                setVisible(true);
+            }
+        };
+    }
+
+    public void updateRewardGraph(double recentReward){
+        rewardHistory.add(recentReward);
+        chart.updateXYSeries("randomWalk", null, rewardHistory, null);
+        rewardChartPanel.revalidate();
+        rewardChartPanel.repaint();
+    }
+
+    public void updateLearningInfoPanel(){
+        this.learningInfoPanel.refreshLabels();
+    }
+
+
+    @Override
+    public void onEpisodeEnd(double sumOfRewards) {
+        SwingUtilities.invokeLater(()->updateRewardGraph(sumOfRewards));
+    }
+
+    @Override
+    public void onEpisodeStart() {
+
+    }
+}

src/main/java/core/gui/Visualizable.java

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+package core.gui;
+
+import javax.swing.*;
+
+public interface Visualizable {
+    JComponent visualize();
+}