Rewrite ConfigGenerator.createClassName to Java.

- In new class ConfiggenUtil.
- This will allow using the function without loading classes
  from scala-xml in the future.
- Do not remove the original scala method, as it could still be
   used for a while by older config models.
  (By classes InstanceResolver and VespaModel.)

1 files changed, 43 insertions, 0 deletions

diff --git a/configgen/src/main/java/com/yahoo/config/codegen/ConfiggenUtil.java b/configgen/src/main/java/com/yahoo/config/codegen/ConfiggenUtil.java
new file mode 100644
index 00000000000..a7a3eb718a3
--- /dev/null
+++ b/configgen/src/main/java/com/yahoo/config/codegen/ConfiggenUtil.java
@@ -0,0 +1,43 @@
+package com.yahoo.config.codegen;
+
+import java.util.Arrays;
+import java.util.stream.Collectors;
+
+/**
+ * @author gjoranv
+ */
+public class ConfiggenUtil {
+
+    /**
+     * Create class name from def name
+     * @param defName The file name without the '.def' suffix
+     */
+    public static String createClassName(String defName) {
+        String className =  Arrays.stream(defName.split("-"))
+                .map(ConfiggenUtil::capitalize)
+                .collect(Collectors.joining())
+                + "Config";
+
+        if (! isLegalJavaIdentifier(className))
+            throw new CodegenRuntimeException("Illegal config definition file name '" + defName +
+                                                      "'. Must be a legal Java identifier.");
+
+        return className;
+    }
+
+    private static String capitalize(String in) {
+        StringBuilder sb = new StringBuilder(in);
+        sb.setCharAt(0, Character.toTitleCase(in.charAt(0)));
+        return sb.toString();
+    }
+
+    private static boolean isLegalJavaIdentifier(String name) {
+        if (name.isEmpty()) return false;
+        if (! Character.isJavaIdentifierStart(name.charAt(0))) return false;
+
+        for (char c : name.substring(1).toCharArray()) {
+            if (! Character.isJavaIdentifierPart(c)) return false;
+        }
+        return true;
+    }
+}