interaction: improve textual visualization of the model

Author: bvlj

lib/src/main/java/jtamaro/interaction/ModelFrame.java

@@ -1,25 +1,42 @@
 package jtamaro.interaction;
 
+import java.awt.Font;
+import java.awt.Insets;
 import java.awt.event.WindowAdapter;
 import java.awt.event.WindowEvent;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+import javax.swing.BorderFactory;
 import javax.swing.JFrame;
 import javax.swing.JScrollPane;
 import javax.swing.JTextArea;
 import jtamaro.data.Sequence;
 
 final class ModelFrame<M> extends JFrame {
 
-  private final JTextArea textArea;
+  private static final Logger LOGGER = Logger.getLogger(ModelFrame.class.getName());
+
+  private static final String EOL = System.lineSeparator();
 
   public ModelFrame(Interaction<M> bang, Trace<M> trace) {
     super();
     setTitle("Model");
-    textArea = new JTextArea(3, 40);
-    add(new JScrollPane(textArea));
+    final JTextArea textArea = new JTextArea();
+    textArea.setMargin(new Insets(8, 8, 8, 8));
+    textArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+    textArea.setEditable(false);
+    textArea.setFocusable(false);
+    final JScrollPane scrollPane = new JScrollPane(textArea);
+    scrollPane.setBorder(BorderFactory.createEmptyBorder());
+    add(scrollPane);
 
     final TraceListener tl = ev -> {
       final M model = getLastModel(trace.getEventSequence(), bang.getInitialModel());
-      textArea.setText(model.toString());
+      textArea.setText(prettyPrint(model, 0));
     };
     // Load current model
     tl.eventAppended(null);
@@ -40,4 +57,57 @@ private M getLastModel(Sequence<TraceEvent<M>> events, M model) {
         ? model
         : events.first().process(getLastModel(events.rest(), model));
   }
+
+  private String prettyPrint(Object obj, int indent) {
+    return switch (obj) {
+      case Sequence<?> seq -> prettyPrintSequence(seq, indent + 1);
+      case Record rec -> prettyPrintRecord(rec, indent + 1);
+      default -> obj.toString();
+    };
+  }
+
+  private String prettyPrintSequence(Sequence<?> seq, int indent) {
+    final String prefix = "  ".repeat(indent) + "• ";
+    return seq.map(it -> prefix + prettyPrint(it, indent))
+        .reduce("", (it, acc) -> acc + EOL + it);
+  }
+
+  private String prettyPrintRecord(Record rec, int indent) {
+    final Class<?> clazz = rec.getClass();
+    final String recName = clazz.getSimpleName();
+    final String prefix = "  ".repeat(indent) + "• ";
+
+    final String contents = Arrays.stream(clazz.getRecordComponents()).map(component -> {
+      final String compName = component.getName();
+      final StringBuilder compSb = new StringBuilder()
+          .append(prefix)
+          .append(compName)
+          .append(": ");
+      try {
+        final Method accessor = component.getAccessor();
+        final boolean isAccessible = accessor.canAccess(rec);
+        if (!isAccessible) {
+          accessor.setAccessible(true);
+        }
+
+        compSb.append(prettyPrint(accessor.invoke(rec), indent));
+
+        if (!isAccessible) {
+          accessor.setAccessible(false);
+        }
+      } catch (IllegalAccessException | InvocationTargetException e) {
+        LOGGER.log(Level.WARNING, "Failed to read component"
+            + compName
+            + " of record class "
+            + recName, e);
+        compSb.append("???");
+      }
+
+      return compSb.toString();
+    }).collect(Collectors.joining(EOL));
+
+    return recName
+        + EOL
+        + contents;
+  }
 }