Move out inner classes

- This refactor moves out the graph classes to their own and provide
  implementations for the Node and Edge. Providing the implementations
  seem to allow for a nicer assertion.
- Also, moved the game-of-life and dots-dsl in the track's config.json
  to sort the practice exercises by difficulty and then name.

config.json

@@ -437,6 +437,17 @@
         ],
         "difficulty": 2
       },
+      {
+        "slug": "dot-dsl",
+        "name": "DOT DSL",
+        "uuid": "03e1070d-a3ed-4664-9559-283e535c6bc4",
+        "practices": [],
+        "prerequisites": [
+          "classes",
+          "lists"
+        ],
+        "difficulty": 2
+      },
       {
         "slug": "grains",
         "name": "Grains",
@@ -916,6 +927,17 @@
         ],
         "difficulty": 5
       },
+      {
+        "slug": "game-of-life",
+        "name": "Conway's Game of Life",
+        "uuid": "749de7fc-3dcb-4231-9b4f-115d153af74f",
+        "practices": [],
+        "prerequisites": [
+          "arrays",
+          "if-statements"
+        ],
+        "difficulty": 5
+      },
       {
         "slug": "grep",
         "name": "Grep",
@@ -1791,27 +1813,6 @@
           "lists"
         ],
         "difficulty": 10
-      },
-      {
-        "slug": "game-of-life",
-        "name": "Conway's Game of Life",
-        "uuid": "749de7fc-3dcb-4231-9b4f-115d153af74f",
-        "practices": [],
-        "prerequisites": [
-          "arrays",
-          "if-statements"
-        ],
-        "difficulty": 5
-      },
-      {
-        "slug": "dot-dsl",
-        "name": "DOT DSL",
-        "uuid": "03e1070d-a3ed-4664-9559-283e535c6bc4",
-        "practices": [],
-        "prerequisites": [
-          "inheritance"
-        ],
-        "difficulty": 5
       }
     ],
     "foregone": [

exercises/practice/dot-dsl/.docs/instructions.append.md

@@ -1,4 +1,6 @@
 # Instructions append
 
-The DSL uses method chaining.
-You can learn more about method chaining [here](https://www.geeksforgeeks.org/method-chaining-in-java-with-examples/).
+The graph is represented in the DSL by the `Graph` class.
+The implementation for the nodes and edges (represented by the `Node` and `Edge` classes respectively) are provided.
+
+For more details on the DSL's expected design, take a look at the test cases in `GraphTest.java`. 

exercises/practice/dot-dsl/.meta/config.json

@@ -1,16 +1,21 @@
 {
   "authors": [
-    "kahgoh"
+    "kahgoh",
+    "manumafe98"
   ],
   "files": {
     "solution": [
-      "src/main/java/DotDsl.java"
+      "src/main/java/Graph.java"
     ],
     "test": [
-      "src/test/java/DotDslTest.java"
+      "src/test/java/GraphTest.java"
     ],
     "example": [
-      ".meta/src/reference/java/DotDsl.java"
+      ".meta/src/reference/java/Graph.java"
+    ],
+    "editor": [
+      "src/main/java/Node.java",
+      "src/main/java/Edge.java"
     ]
   },
   "blurb": "Write a Domain Specific Language similar to the Graphviz dot language.",

exercises/practice/dot-dsl/.meta/src/reference/java/Edge.java

@@ -0,0 +1,48 @@
+import java.util.Collections;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Represents an edge on the graph.
+ *
+ * NOTE: There is no need to change this file and is treated as read only by the Exercism test runners.
+ */
+public final class Edge {
+    private final String start;
+
+    private final String end;
+
+    private final Map<String, String> attributes;
+
+    public Edge(String start, String end) {
+        this.start = start;
+        this.end = end;
+        this.attributes = Collections.emptyMap();
+    }
+
+    public Edge(String start, String end, Map<String, String> attributes) {
+        this.start = start;
+        this.end = end;
+        this.attributes = Map.copyOf(attributes);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(start, end, attributes);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof Edge other) {
+            return Objects.equals(other.start, start)
+                && Objects.equals(other.end, end)
+                && Objects.equals(other.attributes, attributes);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return "Edge [start=" + start + ", end=" + end + ", attributes=" + attributes + "]";
+    }
+}

exercises/practice/dot-dsl/.meta/src/reference/java/Graph.java

@@ -0,0 +1,54 @@
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+public class Graph {
+
+    private final List<Node> nodes = new ArrayList<>();
+
+    private final List<Edge> edges = new ArrayList<>();
+
+    private final Map<String, String> attributes;
+
+    public Graph() {
+        this.attributes = Collections.emptyMap();
+    }
+
+    public Graph(Map<String, String> attributes) {
+        this.attributes = Map.copyOf(attributes);
+    }
+
+    public Collection<Node> getNodes() {
+        return Collections.unmodifiableList(nodes);
+    }
+
+    public Collection<Edge> getEdges() {
+        return Collections.unmodifiableList(edges);
+    }
+
+    public Graph node(String name) {
+        nodes.add(new Node(name));
+        return this;
+    }
+
+    public Graph node(String name, Map<String, String> attributes) {
+        nodes.add(new Node(name, attributes));
+        return this;
+    }
+
+    public Graph edge(String start, String end) {
+        edges.add(new Edge(start, end));
+        return this;
+    }
+
+    public Graph edge(String start, String end, Map<String, String> attributes) {
+        edges.add(new Edge(start, end, attributes));
+        return this;
+    }
+
+    public Map<String, String> getAttributes() {
+        return attributes;
+    }
+}

exercises/practice/dot-dsl/.meta/src/reference/java/Node.java

@@ -0,0 +1,43 @@
+import java.util.Collections;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * Represents a node on the graph.
+ *
+ * NOTE: There is no need to change this file and is treated as read only by the Exercism test runners.
+ */
+public final class Node {
+
+    private final String name;
+
+    private final Map<String, String> attributes;
+
+    public Node(String name) {
+        this.name = name;
+        this.attributes = Collections.emptyMap();
+    }
+
+    public Node(String name, Map<String, String> attributes) {
+        this.name = name;
+        this.attributes = Map.copyOf(attributes);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name, attributes);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof Node other) {
+            return Objects.equals(other.name, name) && Objects.equals(other.attributes, attributes);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return "Node [name=" + name + ", attributes=" + attributes + "]";
+    }
+}