add a LoggingTraverseVisitor for debugging.

Author: fakeholz

opentripplanner-routing/src/main/java/org/opentripplanner/routing/impl/LoggingTraverseVisitor.java

@@ -0,0 +1,27 @@
+package org.opentripplanner.routing.impl;
+
+import org.opentripplanner.routing.algorithm.TraverseVisitor;
+import org.opentripplanner.routing.core.State;
+import org.opentripplanner.routing.graph.Edge;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class LoggingTraverseVisitor implements TraverseVisitor {
+    private static final Logger LOG = LoggerFactory.getLogger(LoggingTraverseVisitor.class);
+
+    @Override
+    public void visitEdge(Edge edge, State state) {
+        String nextName = edge.getName();
+        LOG.info("Traversing edge {}", nextName);
+    }
+
+    @Override
+    public void visitVertex(State state) {
+        LOG.info("Visiting {}", state);
+    }
+
+    @Override
+    public void visitEnqueue(State state) {
+        LOG.info("Enqueing {}", state);
+    }
+}