Add separate API-s for drawing directed and undirected edges

src/main/java/ee/ut/dendroloj/Dendrologist.java

@@ -5,6 +5,7 @@
 import java.awt.Color;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Objects;
 import java.util.function.Function;
 
 public final class Dendrologist {
@@ -224,11 +225,20 @@ private static void drawAdjacencyMatrixGraph(int vertexCount, WeightProvider wei
         GraphCanvas<Number> graphCanvas = new GraphCanvas<>();
         for (int i = 0; i < vertexCount; i++) {
             graphCanvas.drawVertex(i, labels == null ? String.valueOf(i) : labels[i]);
-            for (int j = 0; j < vertexCount; j++) {
+            Number selfWeight = weights.getWeight(i, i);
+            if (selfWeight != null && selfWeight.doubleValue() != 0.0) {
+                graphCanvas.drawEdge(i, i, selfWeight.toString());
+            }
+            for (int j = i + 1; j < vertexCount; j++) {
                 Number weight = weights.getWeight(i, j);
-                if (weight != null && (i != j || weight.doubleValue() != 0.0)) {
-                    graphCanvas.drawEdge(i, j, weight.toString());
+                Number backwardsWeight = weights.getWeight(j, i);
+                if (Objects.equals(weight, backwardsWeight)) {
+                    if (weight != null) graphCanvas.drawEdge(i, j, weight.toString());
+                } else {
+                    if (weight != null) graphCanvas.drawDirectedEdge(i, j, weight.toString());
+                    if (backwardsWeight != null) graphCanvas.drawDirectedEdge(j, i, backwardsWeight.toString());
                 }
+
             }
         }
         Graph graph = GenericGraphLayout.assembleGraph(graphCanvas);

src/main/java/ee/ut/dendroloj/GenericGraphLayout.java

@@ -7,8 +7,6 @@
 import org.graphstream.ui.layout.Layout;
 import org.graphstream.ui.layout.springbox.implementations.SpringBox;
 
-import java.util.concurrent.atomic.AtomicLong;
-
 class GenericGraphLayout {
 
     public static Layout autoLayout() {
@@ -23,7 +21,7 @@ public static Graph assembleGraph(GraphCanvas<?> graphCanvas) {
             if (vertex.color != null) node.setAttribute("ui.color", vertex.color);
         }
         for (var edge : graphCanvas.edges) {
-            Edge graphEdge = graph.addEdge(IdHelper.getNewEdgeId(), IdHelper.getNodeId(edge.from), IdHelper.getNodeId(edge.to), true);
+            Edge graphEdge = graph.addEdge(IdHelper.getNewEdgeId(), IdHelper.getNodeId(edge.v1), IdHelper.getNodeId(edge.v2), edge.directed);
             if (edge.label != null) graphEdge.setAttribute("label", edge.label);
             if (edge.color != null) graphEdge.setAttribute("ui.color", edge.color);
         }

src/main/java/ee/ut/dendroloj/GraphCanvas.java

@@ -19,32 +19,60 @@ public final class GraphCanvas<T> {
 
     public void drawVertex(T vertex) {
         if (vertex == null) throw new NullPointerException("Vertex must not be null");
-        vertices.add(new Vertex<>(vertex, vertex.toString(), null));
+        drawVertex(vertex, vertex.toString(), null);
     }
 
     public void drawVertex(T vertex, String label) {
-        if (vertex == null) throw new NullPointerException("Vertex must not be null");
-        vertices.add(new Vertex<>(vertex, label, null));
+        drawVertex(vertex, label, null);
     }
 
     public void drawVertex(T vertex, String label, Color color) {
         if (vertex == null) throw new NullPointerException("Vertex must not be null");
         vertices.add(new Vertex<>(vertex, label, color));
     }
 
-    public void drawEdge(T from, T to) {
-        if (from == null || to == null) throw new NullPointerException("Target vertices must not be null");
-        edges.add(new Edge<>(from, to, null, null));
+    /**
+     * Draws an undirected edge from vertex v1 to vertex v2.
+     */
+    public void drawEdge(T v1, T v2) {
+        drawEdge(v1, v2, null, null);
+    }
+
+    /**
+     * Draws an undirected edge from vertex v1 to vertex v2.
+     */
+    public void drawEdge(T v1, T v2, String label) {
+        drawEdge(v1, v2, label, null);
+    }
+
+    /**
+     * Draws an undirected edge from vertex v1 to vertex v2.
+     */
+    public void drawEdge(T v1, T v2, String label, Color color) {
+        if (v1 == null || v2 == null) throw new NullPointerException("Target vertices must not be null");
+        edges.add(new Edge<>(false, v1, v2, label, color));
+    }
+
+    /**
+     * Draws a directed edge from vertex v1 to vertex v2.
+     */
+    public void drawDirectedEdge(T v1, T v2) {
+        drawDirectedEdge(v1, v2, null, null);
     }
 
-    public void drawEdge(T from, T to, String label) {
-        if (from == null || to == null) throw new NullPointerException("Target vertices must not be null");
-        edges.add(new Edge<>(from, to, label, null));
+    /**
+     * Draws a directed edge from vertex v1 to vertex v2.
+     */
+    public void drawDirectedEdge(T v1, T v2, String label) {
+        drawDirectedEdge(v1, v2, label, null);
     }
 
-    public void drawEdge(T from, T to, String label, Color color) {
-        if (from == null || to == null) throw new NullPointerException("Target vertices must not be null");
-        edges.add(new Edge<>(from, to, label, color));
+    /**
+     * Draws a directed edge from vertex v1 to vertex v2.
+     */
+    public void drawDirectedEdge(T v1, T v2, String label, Color color) {
+        if (v1 == null || v2 == null) throw new NullPointerException("Target vertices must not be null");
+        edges.add(new Edge<>(true, v1, v2, label, color));
     }
 
     static final class Vertex<T> {
@@ -60,14 +88,16 @@ private Vertex(T vertex, String label, Color color) {
     }
 
     static final class Edge<T> {
-        public final T from;
-        public final T to;
+        public final boolean directed;
+        public final T v1;
+        public final T v2;
         public final String label;
         public final Color color;
 
-        private Edge(T from, T to, String label, Color color) {
-            this.from = from;
-            this.to = to;
+        private Edge(boolean directed, T v1, T v2, String label, Color color) {
+            this.directed = directed;
+            this.v1 = v1;
+            this.v2 = v2;
             this.label = label;
             this.color = color;
         }

src/test/java/GraafKatsed.java

@@ -20,7 +20,7 @@ public static void main(String[] args) {
                 {4, 0, 2, -1, 6},
                 {-1, 2, 0, 3, -1},
                 {12, -1, -1, 0, -1},
-                {-1, -1, 5, 4, 0}
+                {-1, -1, 5, 4, 123}
         };
         Dendrologist.drawGraph(M, nimed);
         // Dendrologist.drawGraph(M, null);