Move Set::hasFlow() to new Algorithm\Flow

Author: clue

src/Flow.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace Fhaculty\Graph\Algorithm;
+
+use Fhaculty\Graph\Algorithm\BaseGraph;
+use Fhaculty\Graph\Edge\Base as Edge;
+use Fhaculty\Graph\Graph;
+
+/**
+ * Basic algorithms for working with flow graphs
+ *
+ * A flow network (also known as a transportation network) is a directed graph
+ * where each edge has a capacity and each edge receives a flow.
+ *
+ * @link http://en.wikipedia.org/wiki/Flow_network
+ * @see Algorithm\Balance
+ */
+class Flow extends BaseSet
+{
+    /**
+     * check if this graph has any flow set (any edge has a non-NULL flow)
+     *
+     * @return boolean
+     * @uses Edge::getFlow()
+     */
+    public function hasFlow()
+    {
+        foreach ($this->set->getEdges() as $edge) {
+            if ($edge->getFlow() !== NULL) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}