Address review feedback: simplify PostProcessor and clean up code

- Replace AbstractVisitor with direct Document child iteration (only
  top-level block quotes are alerts, no need to walk the full tree)
- Remove unnecessary isContentWhitespaceOnly method (the parser never
  produces content nodes for whitespace-only block quote continuations)
- Remove redundant markerText/literal variables, use textNode.getLiteral()
- Restructure afterMarker checks to avoid 3x instanceof repetition
- Add Locale.ROOT to toUpperCase() calls (Turkish locale safety)
- Use var throughout all main source files
- Use single get()+null check instead of containsKey()+get() in renderer
- Add proper Node import in AlertNodeRenderer, remove FQN references
- LinkedHashMap → HashMap in AlertsExtension (ordering not needed)
- Update README: fix outdated custom type docs, align examples with
  AlertsExample.java
- Add screenshots showing rendered alerts with and without icons

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ia3andy

commonmark-ext-gfm-alerts/README.md

@@ -19,22 +19,22 @@ Enables highlighting important information using blockquote syntax with five sta
 #### Standard GFM Types
 
 ```java
-Extension extension = AlertsExtension.create();
-Parser parser = Parser.builder().extensions(List.of(extension)).build();
-HtmlRenderer renderer = HtmlRenderer.builder().extensions(List.of(extension)).build();
+var extension = AlertsExtension.create();
+var parser = Parser.builder().extensions(List.of(extension)).build();
+var renderer = HtmlRenderer.builder().extensions(List.of(extension)).build();
 ```
 
 #### Custom Alert Types
 
 Add custom types beyond the five standard GFM types:
 
 ```java
-Extension extension = AlertsExtension.builder()
-        .addCustomType("INFO", "Information")
+var extension = AlertsExtension.builder()
+        .addCustomType("BUG", "Known Bug")
         .build();
 ```
 
-Custom types must be UPPERCASE and cannot override standard types.
+Custom types must be UPPERCASE. Standard type titles can also be overridden for localization.
 
 #### Styling
 
@@ -63,7 +63,11 @@ Basic CSS example:
 .markdown-alert-caution { border-color: #cf222e; background-color: #ffebe9; }
 ```
 
-Icons can be added using CSS `::before` pseudo-elements with GitHub's [Octicons](https://primer.style/octicons/) (info, light-bulb, report, alert, stop icons).
+![Alerts](screenshots/alerts.png)
+
+Icons can be added using GitHub's [Octicons](https://primer.style/octicons/):
+
+![Alerts with icons](screenshots/alerts-with-icons.png)
 
 ## License
 

commonmark-ext-gfm-alerts/screenshots/alerts-with-icons.png

@@ -13,8 +13,9 @@
 import org.commonmark.renderer.markdown.MarkdownNodeRendererFactory;
 import org.commonmark.renderer.markdown.MarkdownRenderer;
 
+import java.util.HashMap;
+import java.util.Locale;
 import java.util.HashSet;
-import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Set;
 
@@ -34,7 +35,7 @@ public class AlertsExtension implements Parser.ParserExtension, HtmlRenderer.Htm
     private final Map<String, String> customTypes;
 
     private AlertsExtension(Builder builder) {
-        this.customTypes = new LinkedHashMap<>(builder.customTypes);
+        this.customTypes = new HashMap<>(builder.customTypes);
     }
 
     public static Extension create() {
@@ -47,7 +48,7 @@ public static Builder builder() {
 
     @Override
     public void extend(Parser.Builder parserBuilder) {
-        Set<String> allowedTypes = new HashSet<>(STANDARD_TYPES);
+        var allowedTypes = new HashSet<>(STANDARD_TYPES);
         allowedTypes.addAll(customTypes.keySet());
         parserBuilder.postProcessor(new AlertPostProcessor(allowedTypes));
     }
@@ -81,7 +82,7 @@ public Set<Character> getSpecialCharacters() {
      * Builder for configuring the alerts extension.
      */
     public static class Builder {
-        private final Map<String, String> customTypes = new LinkedHashMap<>();
+        private final Map<String, String> customTypes = new HashMap<>();
 
         /**
          * Adds a custom alert type with a display title.
@@ -100,7 +101,7 @@ public Builder addCustomType(String type, String title) {
             if (title == null || title.isEmpty()) {
                 throw new IllegalArgumentException("Title must not be null or empty");
             }
-            if (!type.equals(type.toUpperCase())) {
+            if (!type.equals(type.toUpperCase(Locale.ROOT))) {
                 throw new IllegalArgumentException("Type must be uppercase: " + type);
             }
             customTypes.put(type, title);

commonmark-ext-gfm-alerts/screenshots/alerts.png

@@ -22,11 +22,11 @@ public AlertHtmlNodeRenderer(HtmlNodeRendererContext context, Map<String, String
 
     @Override
     protected void renderAlert(Alert alert) {
-        String type = alert.getType();
-        String cssClass = type.toLowerCase();
+        var type = alert.getType();
+        var cssClass = type.toLowerCase();
 
         htmlWriter.line();
-        Map<String, String> attributes = new LinkedHashMap<>();
+        var attributes = new LinkedHashMap<String, String>();
         attributes.put("class", "markdown-alert markdown-alert-" + cssClass);
         attributes.put("data-alert-type", cssClass);
 
@@ -47,8 +47,9 @@ protected void renderAlert(Alert alert) {
     }
 
     private String getAlertTitle(String type) {
-        if (customTypeTitles.containsKey(type)) {
-            return customTypeTitles.get(type);
+        var customTypeTitle = customTypeTitles.get(type);
+        if (customTypeTitle != null) {
+            return customTypeTitle;
         }
         switch (type) {
             case "NOTE":
@@ -67,9 +68,9 @@ private String getAlertTitle(String type) {
     }
 
     private void renderChildren(Node parent) {
-        Node node = parent.getFirstChild();
+        var node = parent.getFirstChild();
         while (node != null) {
-            Node next = node.getNext();
+            var next = node.getNext();
             context.render(node);
             node = next;
         }

commonmark-ext-gfm-alerts/src/main/java/org/commonmark/ext/gfm/alerts/AlertsExtension.java

@@ -28,9 +28,9 @@ protected void renderAlert(Alert alert) {
     }
 
     private void renderChildren(Node parent) {
-        Node node = parent.getFirstChild();
+        var node = parent.getFirstChild();
         while (node != null) {
-            Node next = node.getNext();
+            var next = node.getNext();
             context.render(node);
             node = next;
         }

commonmark-ext-gfm-alerts/src/main/java/org/commonmark/ext/gfm/alerts/internal/AlertHtmlNodeRenderer.java

@@ -1,20 +1,21 @@
 package org.commonmark.ext.gfm.alerts.internal;
 
 import org.commonmark.ext.gfm.alerts.Alert;
+import org.commonmark.node.Node;
 import org.commonmark.renderer.NodeRenderer;
 
 import java.util.Set;
 
 public abstract class AlertNodeRenderer implements NodeRenderer {
 
     @Override
-    public Set<Class<? extends org.commonmark.node.Node>> getNodeTypes() {
+    public Set<Class<? extends Node>> getNodeTypes() {
         return Set.of(Alert.class);
     }
 
     @Override
-    public void render(org.commonmark.node.Node node) {
-        Alert alert = (Alert) node;
+    public void render(Node node) {
+        var alert = (Alert) node;
         renderAlert(alert);
     }