From c236ab5fcc8e4e93b88238975d9649f77d3ebfcc Mon Sep 17 00:00:00 2001
From: Vincent Paturet <vincent.paturet@entur.org>
Date: Fri, 27 Feb 2026 11:38:45 +0100
Subject: [PATCH] Cache Woodstox XMLInputFactory

---
 .../entur/siri/XmlInputFactoryProvider.java   | 48 +++++++++++++++++++
 .../java/org/entur/siri21/util/SiriXml.java   |  7 +--
 .../org/rutebanken/siri20/util/SiriXml.java   |  7 +--
 3 files changed, 56 insertions(+), 6 deletions(-)
 create mode 100644 src/main/java/org/entur/siri/XmlInputFactoryProvider.java

diff --git a/src/main/java/org/entur/siri/XmlInputFactoryProvider.java b/src/main/java/org/entur/siri/XmlInputFactoryProvider.java
new file mode 100644
index 0000000..f849c20
--- /dev/null
+++ b/src/main/java/org/entur/siri/XmlInputFactoryProvider.java
@@ -0,0 +1,48 @@
+/*
+ * Licensed under the EUPL, Version 1.2 or – as soon they will be approved by
+ * the European Commission - subsequent versions of the EUPL (the "Licence");
+ * You may not use this work except in compliance with the Licence.
+ * You may obtain a copy of the Licence at:
+ *
+ *   https://joinup.ec.europa.eu/software/page/eupl
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the Licence is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the Licence for the specific language governing permissions and
+ * limitations under the Licence.
+ */
+
+package org.entur.siri;
+
+import javax.xml.stream.XMLInputFactory;
+
+/**
+ * Provides a shared {@link XMLInputFactory} when the StAX provider is Woodstox
+ * (thread-safe after initialization), otherwise creates a new factory per call.
+ */
+public class XmlInputFactoryProvider {
+
+    private static final XMLInputFactory SHARED_XML_INPUT_FACTORY = createSharedFactory();
+
+    /**
+     * Returns a shared instance if the StAX provider is Woodstox (thread-safe after
+     * initialization), otherwise creates a new factory per call (spec-safe default).
+     */
+    public static XMLInputFactory getXmlInputFactory() {
+        if (SHARED_XML_INPUT_FACTORY != null) {
+            return SHARED_XML_INPUT_FACTORY;
+        }
+        return XMLInputFactory.newInstance();
+    }
+
+    private static XMLInputFactory createSharedFactory() {
+        XMLInputFactory factory = XMLInputFactory.newInstance();
+        // Woodstox factories are thread-safe after initialization.
+        // https://github.com/FasterXML/Woodstox4/blob/master/release-notes/USAGE
+        if (factory.getClass().getName().startsWith("com.ctc.wstx.")) {
+            return factory;
+        }
+        return null;
+    }
+}
diff --git a/src/main/java/org/entur/siri21/util/SiriXml.java b/src/main/java/org/entur/siri21/util/SiriXml.java
index e1eb126..41c3f46 100644
--- a/src/main/java/org/entur/siri21/util/SiriXml.java
+++ b/src/main/java/org/entur/siri21/util/SiriXml.java
@@ -16,6 +16,7 @@
 package org.entur.siri21.util;
 
 import com.sun.xml.bind.marshaller.NamespacePrefixMapper;
+import org.entur.siri.XmlInputFactoryProvider;
 import uk.org.siri.siri21.Siri;
 
 import jakarta.xml.bind.JAXBContext;
@@ -51,8 +52,8 @@ private static void init() throws JAXBException {
 
     public static Siri parseXml(String xml) throws JAXBException, XMLStreamException {
         Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
-        
-        XMLInputFactory xmlif = XMLInputFactory.newInstance();
+
+        XMLInputFactory xmlif = XmlInputFactoryProvider.getXmlInputFactory();
         XMLStreamReader xmler = xmlif.createXMLStreamReader(new StringReader(xml));
 
         return (Siri) jaxbUnmarshaller.unmarshal(xmler);
@@ -60,7 +61,7 @@ public static Siri parseXml(String xml) throws JAXBException, XMLStreamException
 
     public static Siri parseXml(InputStream inputStream) throws JAXBException, XMLStreamException {
         Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
-        XMLInputFactory xmlif = XMLInputFactory.newInstance();
+        XMLInputFactory xmlif = XmlInputFactoryProvider.getXmlInputFactory();
         XMLStreamReader xmler = xmlif.createXMLStreamReader(inputStream);
 
         return (Siri) jaxbUnmarshaller.unmarshal(xmler);
diff --git a/src/main/java/org/rutebanken/siri20/util/SiriXml.java b/src/main/java/org/rutebanken/siri20/util/SiriXml.java
index fb9451d..538529f 100644
--- a/src/main/java/org/rutebanken/siri20/util/SiriXml.java
+++ b/src/main/java/org/rutebanken/siri20/util/SiriXml.java
@@ -31,6 +31,7 @@
 
 import com.sun.xml.bind.marshaller.NamespacePrefixMapper;
 
+import org.entur.siri.XmlInputFactoryProvider;
 import uk.org.siri.siri20.Siri;
 
 public class SiriXml {
@@ -53,8 +54,8 @@ private static void init() throws JAXBException {
 
     public static Siri parseXml(String xml) throws JAXBException, XMLStreamException {
         Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
-        
-        XMLInputFactory xmlif = XMLInputFactory.newInstance();
+
+        XMLInputFactory xmlif = XmlInputFactoryProvider.getXmlInputFactory();
         XMLStreamReader xmler = xmlif.createXMLStreamReader(new StringReader(xml));
 
         return (Siri) jaxbUnmarshaller.unmarshal(xmler);
@@ -62,7 +63,7 @@ public static Siri parseXml(String xml) throws JAXBException, XMLStreamException
 
     public static Siri parseXml(InputStream inputStream) throws JAXBException, XMLStreamException {
         Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
-        XMLInputFactory xmlif = XMLInputFactory.newInstance();
+        XMLInputFactory xmlif = XmlInputFactoryProvider.getXmlInputFactory();
         XMLStreamReader xmler = xmlif.createXMLStreamReader(inputStream);
 
         return (Siri) jaxbUnmarshaller.unmarshal(xmler);