From a2ad717d04700c4945c36d28b0f665456f100dc4 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 2 May 2026 07:45:59 +0000
Subject: [PATCH] perf: cache compiled XSLT Templates per XSL file in
 MessageCodeGenerator

Agent-Logs-Url: https://github.com/quickfix-j/quickfixj/sessions/e6405c75-ee5e-4d1b-8f7a-7970f31601fb

Co-authored-by: chrjohn <6644028+chrjohn@users.noreply.github.com>
---
 .../codegenerator/MessageCodeGenerator.java   | 29 +++++++++++++++++--
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/quickfixj-codegenerator/src/main/java/org/quickfixj/codegenerator/MessageCodeGenerator.java b/quickfixj-codegenerator/src/main/java/org/quickfixj/codegenerator/MessageCodeGenerator.java
index 615e639661..b2f6ad102e 100644
--- a/quickfixj-codegenerator/src/main/java/org/quickfixj/codegenerator/MessageCodeGenerator.java
+++ b/quickfixj-codegenerator/src/main/java/org/quickfixj/codegenerator/MessageCodeGenerator.java
@@ -27,6 +27,7 @@
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.transform.Templates;
 import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerConfigurationException;
 import javax.xml.transform.TransformerException;
@@ -50,6 +51,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 import javax.xml.XMLConstants;
 
@@ -220,18 +222,39 @@ private void generateComponentClasses(Task task) throws ParserConfigurationExcep
         }
     }
 
+    private final TransformerFactory transformerFactory = new net.sf.saxon.TransformerFactoryImpl();
+
+    private final Map<String, Templates> templatesCache = new ConcurrentHashMap<>();
+
     private Transformer createTransformer(Task task, String xsltFile)
             throws TransformerFactoryConfigurationError, TransformerConfigurationException {
-        StreamSource styleSource;
+        final String cacheKey;
+        final StreamSource styleSource;
         File xslt = new File(task.getTransformDirectory() + "/" + xsltFile);
         if (xslt.exists()) {
+            cacheKey = xslt.getAbsolutePath();
             styleSource = new StreamSource(xslt);
         } else {
             logInfo("Loading predefined xslt file:" + xsltFile);
+            cacheKey = "classpath:" + xsltFile;
             styleSource = new StreamSource(this.getClass().getResourceAsStream(xsltFile));
         }
-        TransformerFactory transformerFactory = new net.sf.saxon.TransformerFactoryImpl();
-        return transformerFactory.newTransformer(styleSource);
+
+        try {
+            Templates templates = templatesCache.computeIfAbsent(cacheKey, k -> {
+                try {
+                    return transformerFactory.newTemplates(styleSource);
+                } catch (TransformerConfigurationException e) {
+                    throw new CodeGenerationException(e);
+                }
+            });
+            return templates.newTransformer();
+        } catch (CodeGenerationException e) {
+            if (e.getCause() instanceof TransformerConfigurationException) {
+                throw (TransformerConfigurationException) e.getCause();
+            }
+            throw e;
+        }
     }
 
     private final Map<String, Document> specificationCache = new HashMap<>();