Enforce immutability via final and unmodifiableList.

src/main/org/insa/graph/Graph.java

@@ -1,60 +1,66 @@
-package org.insa.graph ;
+package org.insa.graph;
 
 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 
 public class Graph {
 
-	// Map identifier.
-	private int mapId;
-	
-	// Nodes of the graph.
-	private ArrayList<Node> nodes;
+    // Map identifier.
+    private final int mapId;
 
-	/**
-	 * @param mapId
-	 * @param nodes
-	 */
-	public Graph(int mapId, ArrayList<Node> nodes) {
-		this.mapId = mapId;
-		this.nodes = nodes;
-	}
-	
-	/**
-	 * @return Nodes of this graph.
-	 */
-	public ArrayList<Node> getNodes() { return nodes; }
-	
-	/**
-	 * Find the closet node to the given point.
-	 * 
-	 * @param point
-	 * 
-	 * @return Closest node to the given point.
-	 */
-	public Node findClosestNode(Point point) {
-		Node node = null;
-		double minDis = Double.POSITIVE_INFINITY;
-		for (int n = 0 ; n < nodes.size(); ++n) {
-			double dis = point.distanceTo(nodes.get(n).getPoint());
-			if (dis < minDis) {
-				node = nodes.get(n);
-				minDis = dis;
-			}
+    // Nodes of the graph.
+    private final ArrayList<Node> nodes;
+
+    /**
+     * @param mapId
+     * @param nodes
+     */
+    public Graph(int mapId, ArrayList<Node> nodes) {
+        this.mapId = mapId;
+        this.nodes = nodes;
+    }
+
+    /**
+     * @return Nodes of this graph.
+     */
+    public List<Node> getNodes() {
+        return Collections.unmodifiableList(nodes);
+    }
+
+    /**
+     * Find the closet node to the given point.
+     * 
+     * @param point
+     * 
+     * @return Closest node to the given point.
+     */
+    public Node findClosestNode(Point point) {
+        Node node = null;
+        double minDis = Double.POSITIVE_INFINITY;
+        for (int n = 0; n < nodes.size(); ++n) {
+            double dis = point.distanceTo(nodes.get(n).getPoint());
+            if (dis < minDis) {
+                node = nodes.get(n);
+                minDis = dis;
+            }
         }
-		return node;
-	}
-	
-	/**
-	 * @return Map ID of this graph.
-	 */
-	public int getMapId() { return mapId; }
-	
-	/**
-	 * @return Return the transpose graph of this graph.
-	 */
-	public Graph transpose() {
-		// TODO: 
-		return null;
-	}
+        return node;
+    }
+
+    /**
+     * @return Map ID of this graph.
+     */
+    public int getMapId() {
+        return mapId;
+    }
+
+    /**
+     * @return Return the transpose graph of this graph.
+     */
+    public Graph transpose() {
+        // TODO:
+        return null;
+    }
 
 }