(accumulo) branch elasticity updated: Add comments (#4189)

[ddanielr]

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ddanielr pushed a commit to branch elasticity
in repository https://gitbox.apache.org/repos/asf/accumulo.git


The following commit(s) were added to refs/heads/elasticity by this push:
     new e364ca6c54 Add comments (#4189)
e364ca6c54 is described below

commit e364ca6c54683c0ba4adadbc452daefccba93168
Author: Daniel Roberts <ddani...@gmail.com>
AuthorDate: Wed Jan 24 15:12:38 2024 -0500

    Add comments (#4189)
    
    Add additional comments for describing the goal of formatString
---
 .../org/apache/accumulo/core/metrics/MetricsUtil.java | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git 
a/core/src/main/java/org/apache/accumulo/core/metrics/MetricsUtil.java 
b/core/src/main/java/org/apache/accumulo/core/metrics/MetricsUtil.java
index 581c30f7eb..311bb5e190 100644
--- a/core/src/main/java/org/apache/accumulo/core/metrics/MetricsUtil.java
+++ b/core/src/main/java/org/apache/accumulo/core/metrics/MetricsUtil.java
@@ -142,29 +142,34 @@ public class MetricsUtil {
   }
 
   /**
-   * Centralize any specific string formatting for metric names and/or tags. 
Ensure strings match
-   * the micrometer naming convention.
+   * This method replaces any intended delimiters with the "." delimiter that 
is used by micrometer.
+   * Micrometer will then transform these delimiters to the metric producer's 
delimiter. Example:
+   * "compactorQueue" becomes "compactor.queue" in micrometer. When using 
Prometheus,
+   * "compactor.queue" would become "compactor_queue".
+   *
    */
   public static String formatString(String name) {
 
-    // Handle spaces
+    // Replace spaces with dot delimiter
     name = name.replace(" ", ".");
-    // Handle snake_case notation
+    // Replace snake_case with dot delimiter
     name = name.replace("_", ".");
-    // Handle Hyphens
+    // Replace hyphens with dot delimiter
     name = name.replace("-", ".");
 
-    // Handle camelCase notation
+    // Insert a dot delimiter before each capital letter found in the regex 
pattern.
     Matcher matcher = camelCasePattern.matcher(name);
     StringBuilder output = new StringBuilder(name);
     int insertCount = 0;
     while (matcher.find()) {
-      // Pattern matches at a lowercase letter, but the insert is at the 
second position.
+      // Pattern matches on a "aAa" pattern and inserts the dot before the 
uppercase character.
+      // Results in "aAa" becoming "a.Aa".
       output.insert(matcher.start() + 1 + insertCount, ".");
       // The correct index position will shift as inserts occur.
       insertCount++;
     }
     name = output.toString();
+    // remove all capital letters after the dot delimiters have been inserted.
     return name.toLowerCase();
   }