refactor: extract LegendPanel from Main.java

Gvisual/src/gvisual/LegendPanel.java

@@ -0,0 +1,47 @@
+package gvisual;
+
+import javax.swing.*;
+import java.awt.*;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * Reusable legend panel that displays a color-coded key for edge types.
+ *
+ * <p>Extracted from {@link Main#initializeLegendSpace()} to separate UI
+ * component construction from the main frame, making it independently
+ * testable and reusable in other views (e.g., headless report generation
+ * or secondary analysis windows).</p>
+ *
+ * @author zalenix
+ */
+public class LegendPanel extends JPanel {
+
+    private static final Map<String, String> LEGEND_ENTRIES = new LinkedHashMap<>();
+    static {
+        LEGEND_ENTRIES.put("Friend", "images/green.jpg");
+        LEGEND_ENTRIES.put("Familiar Stranger", "images/gray.jpg");
+        LEGEND_ENTRIES.put("Stranger", "images/red.jpg");
+        LEGEND_ENTRIES.put("Classmate", "images/blue.jpg");
+        LEGEND_ENTRIES.put("Study Group", "images/yellow.jpg");
+    }
+
+    /**
+     * Creates a legend panel with the default edge-type colour mapping.
+     */
+    public LegendPanel() {
+        JLabel heading = new JLabel("Legend for the Graph");
+        Box vbox = Box.createVerticalBox();
+
+        for (Map.Entry<String, String> entry : LEGEND_ENTRIES.entrySet()) {
+            Box row = Box.createHorizontalBox();
+            row.add(new JLabel(new ImageIcon(entry.getValue())));
+            row.add(new JLabel(entry.getKey()));
+            vbox.add(row);
+        }
+
+        JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
+                heading, vbox);
+        add(splitPane);
+    }
+}

Gvisual/src/gvisual/Main.java

@@ -674,70 +674,7 @@ public void addGraph() throws ParserConfigurationException, IOException, SAXExce
      * initialize the Legend Space
      */
     public final void initializeLegendSpace(){
-        legendPanel = new JPanel();
-
-        JLabel legendHeading = new JLabel("Legend for the Graph");
-
-        String blueImgPath = "images/blue.jpg";
-        String redImgPath = "images/red.jpg";
-        String greenImgPath = "images/green.jpg";
-        String yellowImgPath = "images/yellow.jpg";
-        String grayImgPath = "images/gray.jpg";
-
-        Icon blue = new ImageIcon(blueImgPath);
-        Icon red = new ImageIcon(redImgPath);
-        Icon green = new ImageIcon(greenImgPath);
-        Icon yellow = new ImageIcon(yellowImgPath);
-        Icon gray = new ImageIcon(grayImgPath);
-
-        JLabel fLabel = new JLabel("Friend");
-        JLabel fColor= new JLabel(green);
-        JLabel fsLabel= new JLabel("Familiar Stranger");
-        JLabel fsColor= new JLabel(gray);
-        JLabel sLabel= new JLabel("Stranger");
-        JLabel sColor= new JLabel(red);
-        JLabel cLabel= new JLabel("Classmate");
-        JLabel cColor = new JLabel(blue);
-        JLabel sgLabel= new JLabel("Study Group");
-        JLabel sgColor= new JLabel(yellow);
-
-        Box HBox[] = new Box[5];
-        Box VBox[] = new Box[1];
-
-        VBox[0]= Box.createVerticalBox();
-
-        HBox[0]= Box.createHorizontalBox();
-        HBox[1]= Box.createHorizontalBox();
-        HBox[2]= Box.createHorizontalBox();
-        HBox[3]= Box.createHorizontalBox();
-        HBox[4]= Box.createHorizontalBox();
-
-
-        HBox[0].add(fColor);
-        HBox[1].add(fsColor);
-        HBox[2].add(sColor);
-        HBox[3].add(cColor);
-        HBox[4].add(sgColor);
-
-        HBox[0].add(fLabel);
-        HBox[1].add(fsLabel);
-        HBox[2].add(sLabel);
-        HBox[3].add(cLabel);
-        HBox[4].add(sgLabel);
-
-        VBox[0].add(HBox[0]);
-        VBox[0].add(HBox[1]);
-        VBox[0].add(HBox[2]);
-        VBox[0].add(HBox[3]);
-        VBox[0].add(HBox[4]);
-
-        JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
-                legendHeading, VBox[0]);
-
-
-        legendPanel.add(splitPane);
-
-    }
+        legendPanel = new LegendPanel();
 
     /**
      * Initializes the shortest path finder panel with source/target selection,
@@ -2683,4 +2620,4 @@ public static void main(String[] args) {
                 }
             });
     }
-}
+}