Introduce at least a semblance of thread-safety.

1 files changed, 18 insertions, 17 deletions

diff --git a/org/madore/damlengine/WeblogServlet.java b/org/madore/damlengine/WeblogServlet.java
index 6b9b738..9cf1a75 100644
--- a/org/madore/damlengine/WeblogServlet.java
+++ b/org/madore/damlengine/WeblogServlet.java
@@ -28,7 +28,7 @@ import javax.servlet.http.HttpServletResponse;
 
 public class WeblogServlet extends HttpServlet {
 
-    private static final long serialVersionUID = 2014100406L;
+    private static final long serialVersionUID = 2014100407L;
 
     @Override
     public void doGet(HttpServletRequest request,
@@ -36,22 +36,23 @@ public class WeblogServlet extends HttpServlet {
         throws IOException, ServletException
     {
 
-	DamlEngine.runAsServlet = true;
-	DamlEngine.appProps = new Properties();
-	ServletConfig cfg = getServletConfig();
-	for (Enumeration<String> e = cfg.getInitParameterNames() ; e.hasMoreElements() ; ) {
-	    String k = e.nextElement();
-	    DamlEngine.appProps.setProperty(k, cfg.getInitParameter(k));
-	}
-
-	if ( DamlEngine.appProps.getProperty("base_path") != null )
-	    DamlEngine.basePath = Paths.get(DamlEngine.appProps.getProperty("base_path"));
-	if ( DamlEngine.basePath == null )
-	    DamlEngine.basePath = Paths.get(getServletContext().getRealPath("/"));
-	if ( DamlEngine.appProps.getProperty("template_path") != null )
-	    DamlEngine.templatePath = Paths.get(DamlEngine.appProps.getProperty("template_path"));
-	if ( DamlEngine.templatePath == null )
-	    DamlEngine.templatePath = DamlEngine.basePath.resolve("templates");
+	synchronized ( DamlEngine.class ) { if ( DamlEngine.appProps == null ) {
+	    DamlEngine.runAsServlet = true;
+	    DamlEngine.appProps = new Properties();
+	    ServletConfig cfg = getServletConfig();
+	    for (Enumeration<String> e = cfg.getInitParameterNames() ; e.hasMoreElements() ; ) {
+		String k = e.nextElement();
+		DamlEngine.appProps.setProperty(k, cfg.getInitParameter(k));
+	    }
+	    if ( DamlEngine.appProps.getProperty("base_path") != null )
+		DamlEngine.basePath = Paths.get(DamlEngine.appProps.getProperty("base_path"));
+	    if ( DamlEngine.basePath == null )
+		DamlEngine.basePath = Paths.get(getServletContext().getRealPath("/"));
+	    if ( DamlEngine.appProps.getProperty("template_path") != null )
+		DamlEngine.templatePath = Paths.get(DamlEngine.appProps.getProperty("template_path"));
+	    if ( DamlEngine.templatePath == null )
+		DamlEngine.templatePath = DamlEngine.basePath.resolve("templates");
+	}  }
 
         response.setContentType("text/html; charset=utf-8");
 	response.setCharacterEncoding("UTF-8");