Throw a useful exception when the user agent isn't set on the renderer. This has been a problem for more than one person setting up their own renderer using FOUserAgent.setRendererOverride().

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@649283 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 8 insertions, 1 deletions

diff --git a/src/java/org/apache/fop/render/AbstractRenderer.java b/src/java/org/apache/fop/render/AbstractRenderer.java
index ca3d007d0..816fa4067 100644
--- a/src/java/org/apache/fop/render/AbstractRenderer.java
+++ b/src/java/org/apache/fop/render/AbstractRenderer.java
@@ -124,12 +124,19 @@ public abstract class AbstractRenderer
 
     /** {@inheritDoc} */
     public FOUserAgent getUserAgent() {
+        if (userAgent == null) {
+            throw new IllegalStateException("FOUserAgent has not been set on Renderer");
+        }
         return userAgent;
     }
 
     /** {@inheritDoc} */
     public void startRenderer(OutputStream outputStream)
-        throws IOException { }
+            throws IOException {
+        if (userAgent == null) {
+            throw new IllegalStateException("FOUserAgent has not been set on Renderer");
+        }
+    }
 
     /** {@inheritDoc} */
     public void stopRenderer()