Apply Namer to Java. (#7194)

* Started applying Namer to Java.

- Java didn't previously have keyword escaping
- Added prefixes and suffixes to the Namer methods
- TODO: migrate previous namer applications to using pre/suffixes
- Java methods / functions are interesting, it's mostly camel case
  except when it involves a struct/enum name. That section is Keep case
- I changed the casing for some internal arguments/variables. This
  violates the "don't change genfiles" rule that I've been using but it
  shouldn't break user code.
- LegacyJavaMethod2 is interesting. Basically, Java has a "mixed" case
  convention where it's camel case, except for the type/variant name
  itself, which is keep case. So a type foo_bar would become getfoo_bar
  instead of getFooBar.

* small fix

* Namer for Namespaces

* removed unused parameter, add const everywhere

* Remove unused argument

* More unused args

* Use mutable reference out parameters

* Made more strings const and inlined const empty strings

* remove do not submit

Co-authored-by: Casper Neo <cneo@google.com>

src/namer.h

@@ -112,6 +112,11 @@ class Namer {
     return Method(s.name);
   }
 
+  virtual std::string Method(const std::string &pre,
+                             const std::string &suf) const {
+    return Format(pre + "_" + suf, config_.methods);
+  }
+
   virtual std::string Method(const std::string &s) const {
     return Format(s, config_.methods);
   }
@@ -128,6 +133,15 @@ class Namer {
     return Format(s, config_.variables);
   }
 
+  template<typename T>
+  std::string Variable(const std::string &p, const T &s) const {
+    return Format(p + "_" + s.name, config_.variables);
+  }
+  virtual std::string Variable(const std::string &p,
+                               const std::string &s) const {
+    return Format(p + "_" + s, config_.variables);
+  }
+
   virtual std::string Namespace(const std::string &s) const {
     return Format(s, config_.namespaces);
   }
@@ -191,6 +205,9 @@ class Namer {
   virtual std::string Type(const std::string &s) const {
     return Format(s, config_.types);
   }
+  virtual std::string Type(const std::string &t, const std::string &s) const {
+    return Format(t + "_" + s, config_.types);
+  }
 
   virtual std::string ObjectType(const std::string &s) const {
     return config_.object_prefix + Type(s) + config_.object_suffix;