Some toString impls to make debugging easier.

src/main/java/com/samskivert/mustache/BasicCollector.java

@@ -73,6 +73,9 @@ public abstract class BasicCollector implements Mustache.Collector
             Map<?,?> map = (Map<?,?>)ctx;
             return map.containsKey(name) ? map.get(name) : Template.NO_FETCHER_FOUND;
         }
+        @Override public String toString () {
+            return "MAP_FETCHER";
+        }
     };
 
     protected static final Mustache.VariableFetcher LIST_FETCHER = new Mustache.VariableFetcher() {
@@ -85,6 +88,9 @@ public abstract class BasicCollector implements Mustache.Collector
                 return Template.NO_FETCHER_FOUND;
             }
         }
+        @Override public String toString () {
+            return "LIST_FETCHER";
+        }
     };
 
     protected static final Mustache.VariableFetcher ITER_FETCHER = new Mustache.VariableFetcher() {
@@ -99,12 +105,18 @@ public abstract class BasicCollector implements Mustache.Collector
                 return Template.NO_FETCHER_FOUND;
             }
         }
+        @Override public String toString () {
+            return "ITER_FETCHER";
+        }
     };
 
     protected static final Mustache.VariableFetcher THIS_FETCHER = new Mustache.VariableFetcher() {
         public Object get (Object ctx, String name) throws Exception {
             return ctx;
         }
+        @Override public String toString () {
+            return "THIS_FETCHER";
+        }
     };
 
     protected static abstract class ArrayHelper implements Mustache.VariableFetcher {

src/main/java/com/samskivert/mustache/Template.java

@@ -107,7 +107,7 @@ public class Template
 
     /** A sentinel object that can be returned by a {@link Mustache.Collector} to indicate that a
       * variable does not exist in a particular context. */
-    public static final Object NO_FETCHER_FOUND = new Object();
+    public static final Object NO_FETCHER_FOUND = new String("<no fetcher found>");
 
     /**
      * Executes this template with the given context, returning the results as a string.
@@ -377,6 +377,10 @@ public class Template
             Key okey = (Key)other;
             return okey.cclass == cclass && okey.name == name;
         }
+
+        @Override public String toString () {
+            return cclass.getName() + ":" + name;
+        }
     }
 
     protected static final String DOT_NAME = ".".intern();