fix: x-pattern-message ignored for list items in Spring generator (OpenAPITools#23910)

* fix: x-pattern-message ignored for list items in Spring generator (OpenAPITools#21167)

* Fixed build failure

Author: Natarajan717

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java

@@ -1253,7 +1253,12 @@ private String getStringBeanValidation(Schema<?> items) {
                             .replace("\\", "\\\\")
                             .replace("\"", "\\\""));
 
-            validations = String.format(Locale.ROOT, "@Pattern(regexp = \"%s\")", pattern);
+            String patternMessage = (items.getExtensions() != null)
+                    ? (String) items.getExtensions().get("x-pattern-message")
+                    : null;
+            validations = String.format(Locale.ROOT, "@Pattern(regexp = \"%s\"%s)",
+                    pattern,
+                    (patternMessage != null ? ", message=\"" + patternMessage + "\"" : ""));
         }
 
         if (ModelUtils.isEmailSchema(items)) {

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/AbstractJavaCodegenTest.java

@@ -998,6 +998,21 @@ public void AnnotationsContainerTest() {
         Assert.assertEquals(defaultValue, "List<@Max(10)Integer>");
     }
 
+    @Test
+    public void annotationsContainerPatternMessageTest() {
+        codegen.setUseBeanValidation(true);
+
+        Schema<?> itemSchema = new Schema<>()
+                .type("string")
+                .pattern("^[a-z]$");
+        itemSchema.addExtension("x-pattern-message", "Custom message for list");
+
+        Schema<?> schema = new ArraySchema().items(itemSchema);
+        String defaultValue = codegen.getTypeDeclaration(schema);
+        Assert.assertEquals(defaultValue,
+                "List<@Pattern(regexp = \"^[a-z]$\", message=\"Custom message for list\")String>");
+    }
+
     @Test
     public void disableDiscriminatorJsonIgnorePropertiesFlagTest() {
         codegen.additionalProperties().put(DISABLE_DISCRIMINATOR_JSON_IGNORE_PROPERTIES, true);