Feature: s9api-basierte SaxonWorkerPool-Variante für XSLT 2.0/3.0

Die JAXP-basierte SaxonWorkerPool-Implementierung ist nur für XSLT 1.0
vollständig spezifiziert und kann bei XSLT 2.0/3.0 zu fehlerhaften
Ausgaben führen.

Änderungen:
- Neue SaxonWorkerPoolS9Api-Klasse mit Saxon s9api für XSLT 2.0/3.0
- XsltVersion-Enum in conf.py (XSLT_1_0, XSLT_2_0_3_0)
- ComboBox in Performance-Einstellungen zur XSLT-Version-Auswahl
- MainWindow wählt automatisch richtige Worker-Pool-Variante
- Verbesserte Classpath-Behandlung und Fehlerbehandlung

Standard-Einstellung: XSLT 2.0/3.0 (s9api) - empfohlen für moderne Stylesheets
Fallback: XSLT 1.0 (JAXP) - verfügbar für Legacy-Stylesheets

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/conf.py

@@ -73,6 +73,12 @@ class SSLMode(str, Enum):
     VERIFY_FULL = "verify-full"
 
 
+class XsltVersion(str, Enum):
+    """XSLT-Version für Saxon-Transformationen."""
+    XSLT_1_0 = "1.0"  # JAXP API (nur XSLT 1.0)
+    XSLT_2_0_3_0 = "2.0/3.0"  # s9api (XSLT 2.0 und 3.0)
+
+
 class PostgreSqlDb(BaseModel):
     id: int
     name: str
@@ -144,6 +150,7 @@ class AppSettings(BaseSettings):
     theme: str | None = None
     max_workers: int = 8  # Anzahl paralleler Worker für Transformationen (Standard: 8)
     use_saxon_worker_pool: bool = True  # SaxonWorkerPool aktivieren (schneller, benötigt JDK)
+    saxon_xslt_version: XsltVersion = XsltVersion.XSLT_2_0_3_0  # XSLT-Version für Saxon (Standard: 2.0/3.0 mit s9api)
     use_fop_worker_pool: bool = True  # FopWorkerPool aktivieren (schneller, benötigt JDK)
 
     # UI-Zustand

src/saxon_pool_s9api.py

@@ -0,0 +1,443 @@
+"""
+Saxon Worker Pool (s9api) - Persistente JVM-Prozesse für XSLT 2.0/3.0 Transformationen.
+
+Diese Variante verwendet die Saxon s9api API anstatt JAXP und ist für XSLT 2.0 und 3.0 geeignet.
+Eliminiert JVM-Startup-Overhead durch Vorinitialisierung von N Worker-Prozessen.
+Jeder Worker läuft als Daemon und verarbeitet mehrere Transformationen nacheinander.
+"""
+
+import logging
+import subprocess
+import threading
+from pathlib import Path
+from queue import Queue
+from typing import Optional
+import tempfile
+
+logger = logging.getLogger(__name__)
+
+# Java-Worker-Code für s9api (wird zur Laufzeit kompiliert)
+SAXON_S9API_WORKER_JAVA = """
+import net.sf.saxon.s9api.*;
+import javax.xml.transform.stream.StreamSource;
+import java.io.*;
+
+public class SaxonS9ApiWorker {
+    public static void main(String[] args) {
+        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
+        String line;
+
+        // Create Processor once and reuse (equivalent to TransformerFactory)
+        Processor processor = new Processor(false);
+
+        System.err.println("SaxonS9ApiWorker started and ready (using s9api for XSLT 2.0/3.0)");
+        System.err.flush();
+
+        try {
+            while ((line = reader.readLine()) != null) {
+                System.err.println("DEBUG: Received line: " + line.substring(0, Math.min(100, line.length())));
+                System.err.flush();
+
+                if ("EXIT".equals(line.trim())) {
+                    System.err.println("SaxonS9ApiWorker exiting");
+                    break;
+                }
+
+                try {
+                    // Parse job
+                    System.err.println("DEBUG: Parsing job...");
+                    System.err.flush();
+
+                    String[] parts = line.split("\\\\t");
+                    System.err.println("DEBUG: Parts count: " + parts.length);
+                    System.err.flush();
+
+                    if (parts.length < 3) {
+                        System.out.println("ERROR: Invalid job format");
+                        System.out.flush();
+                        continue;
+                    }
+
+                    String sourceXml = parts[0];
+                    String xslStylesheet = parts[1];
+                    String outputFo = parts[2];
+
+                    System.err.println("DEBUG: Compiling stylesheet...");
+                    System.err.flush();
+
+                    // Compile stylesheet
+                    XsltCompiler compiler = processor.newXsltCompiler();
+                    XsltExecutable executable = compiler.compile(new StreamSource(new File(xslStylesheet)));
+
+                    System.err.println("DEBUG: Creating transformer...");
+                    System.err.flush();
+
+                    // Create transformer
+                    XsltTransformer transformer = executable.load();
+
+                    // Set source
+                    transformer.setSource(new StreamSource(new File(sourceXml)));
+
+                    // Set destination
+                    Serializer serializer = processor.newSerializer(new File(outputFo));
+                    transformer.setDestination(serializer);
+
+                    // Set parameters if present
+                    if (parts.length > 3 && !parts[3].isEmpty()) {
+                        String[] params = parts[3].split("\\\\|\\\\|\\\\|");
+                        for (String param : params) {
+                            if (!param.isEmpty() && param.contains("=")) {
+                                String[] kv = param.split("=", 2);
+                                transformer.setParameter(new QName(kv[0]), new XdmAtomicValue(kv[1]));
+                                System.err.println("DEBUG: Set parameter: " + kv[0] + " = " + kv[1]);
+                            }
+                        }
+                        System.err.flush();
+                    }
+
+                    System.err.println("DEBUG: Running transformation...");
+                    System.err.flush();
+
+                    // Transform
+                    transformer.transform();
+
+                    System.err.println("DEBUG: Transformation completed");
+                    System.err.flush();
+
+                    System.out.println("OK");
+                    System.out.flush();
+
+                } catch (SaxonApiException e) {
+                    System.err.println("DEBUG: SaxonApiException: " + e.getClass().getName());
+                    System.err.flush();
+                    e.printStackTrace(System.err);
+
+                    String errorMsg = e.getMessage();
+                    if (errorMsg == null || errorMsg.isEmpty()) {
+                        errorMsg = e.getClass().getSimpleName();
+                    }
+                    System.out.println("ERROR: " + errorMsg);
+                    System.out.flush();
+
+                } catch (Exception e) {
+                    System.err.println("DEBUG: Job processing exception: " + e.getClass().getName());
+                    System.err.flush();
+                    e.printStackTrace(System.err);
+                    System.out.println("ERROR: " + (e.getMessage() != null ? e.getMessage() : e.getClass().getName()));
+                    System.out.flush();
+                }
+            }
+        } catch (IOException e) {
+            System.err.println("SaxonS9ApiWorker I/O error: " + e.getMessage());
+            e.printStackTrace(System.err);
+        }
+    }
+}
+"""
+
+
+class SaxonWorkerPoolS9Api:
+    """
+    Pool von lang-laufenden JVM-Prozessen für Saxon-Transformationen mit s9api.
+
+    Diese Variante verwendet die Saxon s9api API anstatt JAXP und unterstützt
+    vollständig XSLT 2.0 und 3.0 Transformationen.
+    """
+
+    def __init__(
+        self,
+        num_workers: int,
+        java_vm_path: Path,
+        saxon_jar_path: Path,
+        classpath_cache: dict[Path, str],
+        log_dir: Optional[Path] = None,
+    ):
+        """
+        Initialisiert den Saxon-Worker-Pool mit s9api.
+
+        Args:
+            num_workers: Anzahl der Worker-Prozesse
+            java_vm_path: Pfad zur Java VM Binary
+            saxon_jar_path: Pfad zur Saxon JAR-Datei
+            classpath_cache: Cache für Saxon-Classpaths
+            log_dir: Optionales Verzeichnis für Worker-Logs (Standard: temp_dir/temp)
+        """
+        self.num_workers = num_workers
+        self.java_vm_path = java_vm_path
+        self.saxon_jar_path = saxon_jar_path
+        self.classpath_cache = classpath_cache
+        self.log_dir = log_dir
+
+        # Worker-Prozesse und Queues
+        self.workers: list[subprocess.Popen] = []
+        self.job_queue: Queue = Queue()
+        self.result_queue: Queue = Queue()
+        self.worker_locks: list[threading.Lock] = []
+
+        # Temporäres Verzeichnis für kompilierte Java-Klasse
+        self.temp_dir: Optional[Path] = None
+        self.worker_class_path: Optional[Path] = None
+        self.worker_log_dir: Optional[Path] = None
+
+        # Initialisierung
+        self._compile_worker_class()
+        self._start_workers()
+
+        logger.info(f"SaxonWorkerPoolS9Api initialisiert mit {num_workers} Workern (XSLT 2.0/3.0)")
+
+    def _compile_worker_class(self):
+        """Kompiliert die SaxonS9ApiWorker-Java-Klasse."""
+        try:
+            # Erstelle temporäres Verzeichnis
+            self.temp_dir = Path(tempfile.mkdtemp(prefix="saxon_s9api_worker_"))
+
+            # Schreibe Java-Quellcode
+            java_file = self.temp_dir / "SaxonS9ApiWorker.java"
+            java_file.write_text(SAXON_S9API_WORKER_JAVA, encoding="utf-8")
+
+            # Hole Classpath
+            saxon_dir = self.saxon_jar_path.parent
+            if saxon_dir in self.classpath_cache:
+                classpath = self.classpath_cache[saxon_dir]
+            else:
+                # Fallback: Baue Classpath neu
+                import glob
+                import sys
+
+                all_jars = glob.glob(str(saxon_dir / "*.jar"))
+                lib_dir = saxon_dir / "lib"
+                if lib_dir.exists():
+                    all_jars.extend(glob.glob(str(lib_dir / "*.jar")))
+
+                classpath_separator = ";" if sys.platform == "win32" else ":"
+                classpath = classpath_separator.join(all_jars)
+
+            # Kompiliere Java-Klasse
+            javac_cmd = [str(self.java_vm_path).replace("java", "javac"), "-cp", classpath, str(java_file)]
+
+            logger.debug(f"Kompiliere SaxonS9ApiWorker: {' '.join(javac_cmd)}")
+
+            result = subprocess.run(javac_cmd, capture_output=True, text=True, timeout=30)
+
+            if result.returncode != 0:
+                raise RuntimeError(f"Java-Kompilierung fehlgeschlagen: {result.stderr}")
+
+            self.worker_class_path = self.temp_dir
+
+            logger.info(f"SaxonS9ApiWorker erfolgreich kompiliert: {self.temp_dir}")
+
+        except Exception as e:
+            logger.error(f"Fehler beim Kompilieren von SaxonS9ApiWorker: {e}")
+            raise
+
+    def _start_workers(self):
+        """Startet N Worker-Prozesse."""
+        # Hole Classpath
+        saxon_dir = self.saxon_jar_path.parent
+        if saxon_dir in self.classpath_cache:
+            classpath = self.classpath_cache[saxon_dir]
+        else:
+            # Fallback: Baue Classpath neu (sollte nicht nötig sein, aber zur Sicherheit)
+            import glob
+            import sys
+
+            all_jars = glob.glob(str(saxon_dir / "*.jar"))
+            lib_dir = saxon_dir / "lib"
+            if lib_dir.exists():
+                all_jars.extend(glob.glob(str(lib_dir / "*.jar")))
+
+            classpath_separator = ";" if sys.platform == "win32" else ":"
+            classpath = classpath_separator.join(all_jars)
+
+            # Cache für zukünftige Verwendung
+            self.classpath_cache[saxon_dir] = classpath
+            logger.debug(f"Classpath für {saxon_dir} neu erstellt und gecacht")
+
+        # Füge Worker-Classpath hinzu
+        import sys
+
+        classpath_separator = ";" if sys.platform == "win32" else ":"
+        full_classpath = str(self.worker_class_path) + classpath_separator + classpath
+
+        logger.debug(f"S9Api Worker Classpath: {full_classpath[:200]}...")
+
+        # Bestimme Log-Verzeichnis
+        self.worker_log_dir = self.log_dir if self.log_dir else self.temp_dir
+        if self.log_dir:
+            self.worker_log_dir.mkdir(parents=True, exist_ok=True)
+
+        for i in range(self.num_workers):
+            try:
+                # Starte JVM-Prozess mit SaxonS9ApiWorker
+                cmd = [str(self.java_vm_path), "-cp", full_classpath, "SaxonS9ApiWorker"]
+
+                # Öffne stderr-Log-Datei für diesen Worker
+                stderr_log = self.worker_log_dir / f"s9api_worker_{i}_stderr.log"
+                stderr_file = open(stderr_log, "w", encoding="utf-8")
+
+                process = subprocess.Popen(
+                    cmd,
+                    stdin=subprocess.PIPE,
+                    stdout=subprocess.PIPE,
+                    stderr=stderr_file,  # Redirect stderr to file
+                    text=True,
+                    bufsize=1,  # Line buffered
+                )
+
+                self.workers.append(process)
+                self.worker_locks.append(threading.Lock())
+
+                logger.debug(f"S9Api Worker {i} gestartet (PID: {process.pid}, stderr: {stderr_log})")
+
+                # Warte kurz damit Worker initialisieren kann
+                import time
+
+                time.sleep(0.1)
+
+                # Prüfe ob Worker noch läuft
+                if process.poll() is not None:
+                    # Worker ist bereits beendet - Fehler!
+                    stderr_file.close()
+                    with open(stderr_log, "r") as f:
+                        stderr_content = f.read()
+                    raise RuntimeError(
+                        f"S9Api Worker {i} ist sofort beendet (Exit Code: {process.returncode})\nstderr:\n{stderr_content}"
+                    )
+
+            except Exception as e:
+                logger.error(f"Fehler beim Starten von S9Api Worker {i}: {e}")
+                raise
+
+        logger.info(f"{len(self.workers)} Saxon-S9Api-Worker erfolgreich gestartet")
+
+    def transform(
+        self, source_xml: Path, xsl_stylesheet: Path, output_fo: Path, xslt_params: dict[str, str]
+    ) -> tuple[bool, str]:
+        """
+        Führt eine XSLT-Transformation mit einem Worker aus dem Pool aus.
+
+        Args:
+            source_xml: Pfad zur XML-Eingabedatei
+            xsl_stylesheet: Pfad zur XSL-Stylesheet-Datei
+            output_fo: Pfad zur FO-Ausgabedatei
+            xslt_params: Dictionary mit XSLT-Parametern
+
+        Returns:
+            tuple[bool, str]: (Erfolg, Fehlermeldung/Info)
+        """
+        # Finde freien Worker
+        worker_idx = None
+        for i, lock in enumerate(self.worker_locks):
+            if lock.acquire(blocking=False):
+                worker_idx = i
+                break
+
+        if worker_idx is None:
+            # Kein freier Worker, warte auf ersten verfügbaren
+            for i, lock in enumerate(self.worker_locks):
+                lock.acquire()
+                worker_idx = i
+                break
+
+        try:
+            worker = self.workers[worker_idx]
+
+            # Prüfe ob Worker noch läuft
+            if worker.poll() is not None:
+                # Worker ist tot!
+                stderr_log = self.worker_log_dir / f"s9api_worker_{worker_idx}_stderr.log"
+                try:
+                    with open(stderr_log, "r") as f:
+                        stderr_content = f.read()
+                    error_msg = (
+                        f"S9Api Worker {worker_idx} ist beendet (Exit: {worker.returncode})\nstderr:\n{stderr_content}"
+                    )
+                except Exception:
+                    error_msg = f"S9Api Worker {worker_idx} ist beendet (Exit: {worker.returncode})"
+                logger.error(error_msg)
+                return False, error_msg
+
+            # Formatiere Parameter
+            params_str = "|||".join([f"{key}={value}" for key, value in xslt_params.items()])
+
+            # Erstelle Job-String (Tab-separated)
+            job = f"{source_xml}\t{xsl_stylesheet}\t{output_fo}\t{params_str}\n"
+
+            logger.debug(f"Sende Job an S9Api Worker {worker_idx}: {source_xml.name}")
+
+            # Sende Job an Worker
+            worker.stdin.write(job)
+            worker.stdin.flush()
+
+            # Warte auf Antwort
+            response = worker.stdout.readline().strip()
+
+            logger.debug(f"S9Api Worker {worker_idx} Antwort: '{response}'")
+
+            if response == "OK":
+                return True, "Erfolgreich"
+            elif response.startswith("ERROR:"):
+                error_msg = response[6:].strip()
+                return False, f"Saxon-Fehler (s9api): {error_msg}"
+            else:
+                # Leere Antwort bedeutet Worker ist crashed
+                if not response:
+                    stderr_log = self.worker_log_dir / f"s9api_worker_{worker_idx}_stderr.log"
+                    try:
+                        with open(stderr_log, "r") as f:
+                            stderr_content = f.read()[-500:]  # Letzte 500 Zeichen
+                        return False, f"S9Api Worker {worker_idx} crashed (keine Antwort)\nstderr:\n{stderr_content}"
+                    except Exception:
+                        return False, f"S9Api Worker {worker_idx} crashed (keine Antwort)"
+                return False, f"Unerwartete Antwort: {response}"
+
+        except Exception as e:
+            logger.error(f"Fehler bei S9Api Worker {worker_idx}: {e}")
+            return False, f"Worker-Fehler: {str(e)}"
+
+        finally:
+            # Gebe Worker-Lock frei
+            self.worker_locks[worker_idx].release()
+
+    def shutdown(self):
+        """Beendet alle Worker-Prozesse sauber."""
+        logger.info("Beende Saxon-S9Api-Worker-Pool...")
+
+        for i, worker in enumerate(self.workers):
+            try:
+                # Sende EXIT-Befehl
+                if worker.stdin and not worker.stdin.closed:
+                    worker.stdin.write("EXIT\n")
+                    worker.stdin.flush()
+
+                # Warte auf Beendigung (max 2 Sekunden)
+                worker.wait(timeout=2)
+                logger.debug(f"S9Api Worker {i} beendet")
+
+            except subprocess.TimeoutExpired:
+                # Force kill falls nötig
+                worker.kill()
+                logger.warning(f"S9Api Worker {i} musste gekillt werden")
+
+            except Exception as e:
+                logger.error(f"Fehler beim Beenden von S9Api Worker {i}: {e}")
+
+        # Lösche temporäres Verzeichnis
+        if self.temp_dir and self.temp_dir.exists():
+            try:
+                import shutil
+
+                shutil.rmtree(self.temp_dir)
+                logger.debug(f"Temporäres Verzeichnis gelöscht: {self.temp_dir}")
+            except Exception as e:
+                logger.warning(f"Konnte temporäres Verzeichnis nicht löschen: {e}")
+
+        logger.info("Saxon-S9Api-Worker-Pool beendet")
+
+    def __enter__(self):
+        """Context manager entry."""
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        """Context manager exit."""
+        self.shutdown()

src/transform.py

@@ -15,18 +15,20 @@ from typing import Any, Optional, TYPE_CHECKING
 
 if TYPE_CHECKING:
     from saxon_pool import SaxonWorkerPool
+    from saxon_pool_s9api import SaxonWorkerPoolS9Api
     from fop_pool import FopWorkerPool
 
 logger = logging.getLogger(__name__)
 
 # Globaler Saxon-Worker-Pool (wird von MainWindow initialisiert)
-_saxon_worker_pool: Optional["SaxonWorkerPool"] = None
+# Kann entweder JAXP oder s9api Variante sein
+_saxon_worker_pool: Optional["SaxonWorkerPool | SaxonWorkerPoolS9Api"] = None
 
 # Globaler FOP-Worker-Pool (wird von MainWindow initialisiert)
 _fop_worker_pool: Optional["FopWorkerPool"] = None
 
 
-def set_saxon_worker_pool(pool: Optional["SaxonWorkerPool"]):
+def set_saxon_worker_pool(pool: Optional["SaxonWorkerPool | SaxonWorkerPoolS9Api"]):
     """Setzt den globalen Saxon-Worker-Pool."""
     global _saxon_worker_pool
     _saxon_worker_pool = pool

src/ui/AppSettings.py

@@ -10,7 +10,7 @@ from ui.ApacheFopConfigDialog import ApacheFopConfigDialog
 from ui.XslDirConfigDialog import XslDirConfigDialog
 from ui.PostgreSqlConfigDialog import PostgreSqlConfigDialog
 from ui.PdfProject import PdfProjectDlg
-from conf import AppSettings, JavaVm, DiffPdf, SaxonJar, ApacheFop, XslDir, Project, PostgreSqlDb
+from conf import AppSettings, JavaVm, DiffPdf, SaxonJar, ApacheFop, XslDir, Project, PostgreSqlDb, XsltVersion
 
 
 class AppSettingsDlg(QDialog):
@@ -282,6 +282,12 @@ class AppSettingsDlg(QDialog):
         # SaxonWorkerPool-Checkbox setzen
         self.ui.checkBoxUseSaxonPool.setChecked(self.settings.use_saxon_worker_pool)
 
+        # XSLT-Version ComboBox setzen
+        if self.settings.saxon_xslt_version == XsltVersion.XSLT_1_0:
+            self.ui.comboBoxXsltVersion.setCurrentIndex(0)
+        else:  # XSLT_2_0_3_0
+            self.ui.comboBoxXsltVersion.setCurrentIndex(1)
+
         # FopWorkerPool-Checkbox setzen
         self.ui.checkBoxUseFopPool.setChecked(self.settings.use_fop_worker_pool)
 
@@ -740,6 +746,13 @@ class AppSettingsDlg(QDialog):
         # Performance-Einstellungen übernehmen
         self.settings.max_workers = self.ui.spinBoxWorkerCount.value()
         self.settings.use_saxon_worker_pool = self.ui.checkBoxUseSaxonPool.isChecked()
+
+        # XSLT-Version übernehmen
+        if self.ui.comboBoxXsltVersion.currentIndex() == 0:
+            self.settings.saxon_xslt_version = XsltVersion.XSLT_1_0
+        else:
+            self.settings.saxon_xslt_version = XsltVersion.XSLT_2_0_3_0
+
         self.settings.use_fop_worker_pool = self.ui.checkBoxUseFopPool.isChecked()
 
         self.settings.save()

src/ui/AppSettings.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>833</width>
-    <height>446</height>
+    <height>526</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -20,7 +20,7 @@
       <bool>true</bool>
      </property>
      <property name="currentIndex">
-      <number>0</number>
+      <number>7</number>
      </property>
      <property name="elideMode">
       <enum>Qt::TextElideMode::ElideRight</enum>
@@ -580,6 +580,55 @@ Deaktivieren Sie diese Option, wenn:
             </property>
            </widget>
           </item>
+          <item>
+           <layout class="QHBoxLayout" name="horizontalLayoutXsltVersion">
+            <item>
+             <widget class="QLabel" name="labelXsltVersion">
+              <property name="text">
+               <string>XSLT-Version:</string>
+              </property>
+             </widget>
+            </item>
+            <item>
+             <widget class="QComboBox" name="comboBoxXsltVersion">
+              <property name="toolTip">
+               <string>Wählen Sie die XSLT-Version für Saxon-Transformationen:
+
+XSLT 1.0 (JAXP): Verwendet die JAXP Transformer API
+• Nur für XSLT 1.0 vollständig spezifiziert
+• Kann bei XSLT 2.0/3.0 zu fehlerhaften Ausgaben führen
+
+XSLT 2.0/3.0 (s9api): Verwendet die Saxon s9api
+• Vollständige Unterstützung für XSLT 2.0 und 3.0
+• Empfohlen für moderne XSLT-Stylesheets</string>
+              </property>
+              <item>
+               <property name="text">
+                <string>XSLT 1.0 (JAXP)</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>XSLT 2.0/3.0 (s9api) - Empfohlen</string>
+               </property>
+              </item>
+             </widget>
+            </item>
+            <item>
+             <spacer name="horizontalSpacerXsltVersion">
+              <property name="orientation">
+               <enum>Qt::Orientation::Horizontal</enum>
+              </property>
+              <property name="sizeHint" stdset="0">
+               <size>
+                <width>40</width>
+                <height>20</height>
+               </size>
+              </property>
+             </spacer>
+            </item>
+           </layout>
+          </item>
           <item>
            <widget class="QLabel" name="labelSaxonPoolInfo">
             <property name="text">
@@ -629,6 +678,19 @@ Deaktivieren Sie diese Option, wenn:
          </layout>
         </widget>
        </item>
+       <item>
+        <spacer name="verticalSpacer">
+         <property name="orientation">
+          <enum>Qt::Orientation::Vertical</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>20</width>
+           <height>40</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
        <item>
         <widget class="QLabel" name="label">
          <property name="mouseTracking">

src/ui/AppSettings_ui.py

@@ -15,17 +15,17 @@ from PySide6.QtGui import (QBrush, QColor, QConicalGradient, QCursor,
     QFont, QFontDatabase, QGradient, QIcon,
     QImage, QKeySequence, QLinearGradient, QPainter,
     QPalette, QPixmap, QRadialGradient, QTransform)
-from PySide6.QtWidgets import (QAbstractButton, QApplication, QCheckBox, QDialog,
-    QDialogButtonBox, QFrame, QGroupBox, QHBoxLayout,
-    QHeaderView, QLabel, QPushButton, QSizePolicy,
-    QSpacerItem, QSpinBox, QTabWidget, QTableWidget,
-    QTableWidgetItem, QVBoxLayout, QWidget)
+from PySide6.QtWidgets import (QAbstractButton, QApplication, QCheckBox, QComboBox,
+    QDialog, QDialogButtonBox, QFrame, QGroupBox,
+    QHBoxLayout, QHeaderView, QLabel, QPushButton,
+    QSizePolicy, QSpacerItem, QSpinBox, QTabWidget,
+    QTableWidget, QTableWidgetItem, QVBoxLayout, QWidget)
 
 class Ui_Dialog(object):
     def setupUi(self, Dialog):
         if not Dialog.objectName():
             Dialog.setObjectName(u"Dialog")
-        Dialog.resize(833, 446)
+        Dialog.resize(833, 526)
         self.verticalLayout = QVBoxLayout(Dialog)
         self.verticalLayout.setObjectName(u"verticalLayout")
         self.tabSettings = QTabWidget(Dialog)
@@ -336,6 +336,27 @@ class Ui_Dialog(object):
 
         self.verticalLayout_11.addWidget(self.checkBoxUseSaxonPool)
 
+        self.horizontalLayoutXsltVersion = QHBoxLayout()
+        self.horizontalLayoutXsltVersion.setObjectName(u"horizontalLayoutXsltVersion")
+        self.labelXsltVersion = QLabel(self.groupBoxSaxonPool)
+        self.labelXsltVersion.setObjectName(u"labelXsltVersion")
+
+        self.horizontalLayoutXsltVersion.addWidget(self.labelXsltVersion)
+
+        self.comboBoxXsltVersion = QComboBox(self.groupBoxSaxonPool)
+        self.comboBoxXsltVersion.addItem("")
+        self.comboBoxXsltVersion.addItem("")
+        self.comboBoxXsltVersion.setObjectName(u"comboBoxXsltVersion")
+
+        self.horizontalLayoutXsltVersion.addWidget(self.comboBoxXsltVersion)
+
+        self.horizontalSpacerXsltVersion = QSpacerItem(40, 20, QSizePolicy.Policy.Expanding, QSizePolicy.Policy.Minimum)
+
+        self.horizontalLayoutXsltVersion.addItem(self.horizontalSpacerXsltVersion)
+
+
+        self.verticalLayout_11.addLayout(self.horizontalLayoutXsltVersion)
+
         self.labelSaxonPoolInfo = QLabel(self.groupBoxSaxonPool)
         self.labelSaxonPoolInfo.setObjectName(u"labelSaxonPoolInfo")
         self.labelSaxonPoolInfo.setWordWrap(True)
@@ -363,6 +384,10 @@ class Ui_Dialog(object):
 
         self.verticalLayout_9.addWidget(self.groupBoxFopPool)
 
+        self.verticalSpacer = QSpacerItem(20, 40, QSizePolicy.Policy.Minimum, QSizePolicy.Policy.Expanding)
+
+        self.verticalLayout_9.addItem(self.verticalSpacer)
+
         self.label = QLabel(self.tabPerformance)
         self.label.setObjectName(u"label")
         self.label.setMouseTracking(True)
@@ -392,7 +417,7 @@ class Ui_Dialog(object):
         self.buttonBox.accepted.connect(Dialog.accept)
         self.buttonBox.rejected.connect(Dialog.reject)
 
-        self.tabSettings.setCurrentIndex(0)
+        self.tabSettings.setCurrentIndex(7)
 
 
         QMetaObject.connectSlotsByName(Dialog)
@@ -438,6 +463,21 @@ class Ui_Dialog(object):
 "\u2022 Sie die Funktion testen m\u00f6chten", None))
 #endif // QT_CONFIG(tooltip)
         self.checkBoxUseSaxonPool.setText(QCoreApplication.translate("Dialog", u"SaxonWorkerPool verwenden (empfohlen)", None))
+        self.labelXsltVersion.setText(QCoreApplication.translate("Dialog", u"XSLT-Version:", None))
+        self.comboBoxXsltVersion.setItemText(0, QCoreApplication.translate("Dialog", u"XSLT 1.0 (JAXP)", None))
+        self.comboBoxXsltVersion.setItemText(1, QCoreApplication.translate("Dialog", u"XSLT 2.0/3.0 (s9api) - Empfohlen", None))
+
+#if QT_CONFIG(tooltip)
+        self.comboBoxXsltVersion.setToolTip(QCoreApplication.translate("Dialog", u"W\u00e4hlen Sie die XSLT-Version f\u00fcr Saxon-Transformationen:\n"
+"\n"
+"XSLT 1.0 (JAXP): Verwendet die JAXP Transformer API\n"
+"\u2022 Nur f\u00fcr XSLT 1.0 vollst\u00e4ndig spezifiziert\n"
+"\u2022 Kann bei XSLT 2.0/3.0 zu fehlerhaften Ausgaben f\u00fchren\n"
+"\n"
+"XSLT 2.0/3.0 (s9api): Verwendet die Saxon s9api\n"
+"\u2022 Vollst\u00e4ndige Unterst\u00fctzung f\u00fcr XSLT 2.0 und 3.0\n"
+"\u2022 Empfohlen f\u00fcr moderne XSLT-Stylesheets", None))
+#endif // QT_CONFIG(tooltip)
         self.labelSaxonPoolInfo.setText(QCoreApplication.translate("Dialog", u"<i>Hinweis: SaxonWorkerPool ben\u00f6tigt ein JDK (Java Development Kit).<br>Mit JRE allein werden Transformationen im Fallback-Modus ausgef\u00fchrt.</i>", None))
         self.groupBoxFopPool.setTitle(QCoreApplication.translate("Dialog", u"FopWorkerPool Einstellungen", None))
 #if QT_CONFIG(tooltip)

src/ui/MainWindow.py

@@ -28,9 +28,10 @@ from ui.PdfProject import PdfProjectDlg
 from ui.TreeNodeEditDialog import TreeNodeEditDialog
 from ui.XslFileEditDialog import XslFileEditDialog
 from ui.XmlToXslAssignDialog import XmlToXslAssignDialog
-from conf import app_settings, Project, ProjectData, TreeNode, XslFile, XmlFile
+from conf import app_settings, Project, ProjectData, TreeNode, XslFile, XmlFile, XsltVersion
 from transform import TransformationJob, set_saxon_worker_pool
 from saxon_pool import SaxonWorkerPool
+from saxon_pool_s9api import SaxonWorkerPoolS9Api
 from pathlib import Path
 
 
@@ -727,9 +728,13 @@ class MainWindow(QMainWindow):
                 logger.warning("Java VM oder Saxon JAR nicht gefunden, Pool nicht initialisiert")
                 return
 
-            # Erstelle Worker-Pool
+            # Erstelle Worker-Pool (wähle richtige Variante basierend auf XSLT-Version)
             num_workers = app_settings.max_workers
             log_dir = self.project.project_dir / "temp"
+
+            # Wähle die richtige Worker-Pool-Implementierung
+            if app_settings.saxon_xslt_version == XsltVersion.XSLT_1_0:
+                # JAXP-basierte Variante für XSLT 1.0
                 pool = SaxonWorkerPool(
                     num_workers=num_workers,
                     java_vm_path=java_vm.path_to_binary_file,
@@ -737,12 +742,23 @@ class MainWindow(QMainWindow):
                     classpath_cache=TransformationJob._classpath_cache,
                     log_dir=log_dir,
                 )
+                pool_type = "JAXP (XSLT 1.0)"
+            else:
+                # s9api-basierte Variante für XSLT 2.0/3.0
+                pool = SaxonWorkerPoolS9Api(
+                    num_workers=num_workers,
+                    java_vm_path=java_vm.path_to_binary_file,
+                    saxon_jar_path=saxon_jar.path_to_jar_file,
+                    classpath_cache=TransformationJob._classpath_cache,
+                    log_dir=log_dir,
+                )
+                pool_type = "s9api (XSLT 2.0/3.0)"
 
             # Setze globalen Pool
             set_saxon_worker_pool(pool)
 
             logger.info(
-                f"Saxon-Worker-Pool initialisiert: {num_workers} Worker "
+                f"Saxon-Worker-Pool initialisiert: {num_workers} Worker mit {pool_type} "
                 f"(erwartet: {num_workers}x schneller für Saxon-Transformationen)"
             )