[Patch] Use visitor pattern for key/value lookup.

[michael2402]

Currently, MapCSS creates a HashMap to get the keys from each primitive.

We can speed this up a lot using a visitor pattern.

[simon04]

Looks good to me. Seems to be a safer alternative to #11653.

[simon04]

In 8740/josm:

fix #11834 - Use visitor pattern for key/value lookup (patch by michael2402, slightly modified)

[simon04]

While attempting to use this visitor for the UntaggedNode test, I needed also to obtain the current primitive. The following modification also provides the primitive to the visitor (which can be ignored when not needed). What do you think?

src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java

@@ -37 +37 @@
         /**
          * This method gets called for every tag received.
          *
+         * @param primitive This primitive
          * @param key   The key
          * @param value The value
          */
-        void visitKeyValue(String key, String value);
+        void visitKeyValue(AbstractPrimitive primitive, String key, String value);
     }
 
     private static final AtomicLong idCounter = new AtomicLong(0);
@@ -519 +520 @@
         final String[] keys = this.keys;
         if (keys != null) {
             for (int i = 0; i < keys.length; i += 2) {
-                visitor.visitKeyValue(keys[i], keys[i + 1]);
+                visitor.visitKeyValue(this, keys[i], keys[i + 1]);
             }
         }
     }

[michael2402]

This is a good improvement. The overhead should be minimal (since we are only passing one more parameter).

Don't you rather want to use a visitor for each node in that test? You could let it collect all information for the node and then display the result. Performance should not be that critical there.

[simon04]

In 8742/josm:

fix #11834 - KeyValueVisitor: also provide primitive to the visitor

[simon04]

In 8743/josm:

see #11834 - Use KeyValueVisitor in the UntaggedNode test