Fix #2880 by reverting part of change for #2715 (reintroduce deprecated constants)

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -9,6 +9,8 @@ Project: jackson-databind
 
 #2878: Revert change initially made to fix #2805: change in signature
   of `ObjectMapper.treeToValue()` regarding exceptions
+#2880: Revert removal of 2.7-deprecated `PropertyNamingStrategy` constants
+ (reported by brettkail-wk@github)
 
 2.12.0-rc1 (12-Oct-2020)
 

src/main/java/com/fasterxml/jackson/databind/PropertyNamingStrategy.java

@@ -387,4 +387,34 @@ public String translate(String input){
             return translateLowerCaseWithSeparator(input, '.');
         }
     }
+
+    /*
+    /**********************************************************
+    /* Deprecated variants, aliases
+    /**********************************************************
+     */
+
+    /**
+     * @deprecated Since 2.7 use {@link PropertyNamingStrategies#SNAKE_CASE} instead.
+     */
+    @Deprecated // since 2.7
+    public static final PropertyNamingStrategy CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES = SNAKE_CASE;
+
+    /**
+     * @deprecated Since 2.7 use {@link PropertyNamingStrategies#UPPER_CAMEL_CASE} instead;
+     */
+    @Deprecated // since 2.7
+    public static final PropertyNamingStrategy PASCAL_CASE_TO_CAMEL_CASE = UPPER_CAMEL_CASE;
+
+    /**
+     * @deprecated In 2.7 use {@link PropertyNamingStrategies#SnakeCaseStrategy} instead
+     */
+    @Deprecated // since 2.7
+    public static class LowerCaseWithUnderscoresStrategy extends SnakeCaseStrategy {}
+
+    /**
+     * @deprecated In 2.7 use {@link PropertyNamingStrategies#UpperCamelCaseStrategy} instead
+     */
+    @Deprecated // since 2.7
+    public static class PascalCaseStrategy extends UpperCamelCaseStrategy { }
 }