Added safe-guard against reuse to avoid problems with the renderers.

Removed reset() method. Compared to the many hundred object instances that get created by the FO tree and layout engine, the Fop and FOTreeBuilder instance are negligible. Better keep the API as simple as possible and create an environmental class in the long run.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@372880 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/src/java/org/apache/fop/fo/FOTreeBuilder.java b/src/java/org/apache/fop/fo/FOTreeBuilder.java
index c0aa87a4422245e2751d0ca05e768a48ed73208d..f674d58c842be360a5197a7e922cb8305938bde7 100644 (file)
--- a/src/java/org/apache/fop/fo/FOTreeBuilder.java
+++ b/src/java/org/apache/fop/fo/FOTreeBuilder.java
@@ -48,6 +48,8 @@ public class FOTreeBuilder extends DefaultHandler {
 
     /** The registry for ElementMapping instances */
     protected ElementMappingRegistry elementMappingRegistry;
+    //TODO Remove the ElementMappingRegistry from here and move it to a new environmental class
+    //FOTreeBuilder should be a "one-use" component.
     
     /**
      * The root of the formatting object tree
@@ -76,6 +78,8 @@ public class FOTreeBuilder extends DefaultHandler {
     /** The user agent for this processing run. */
     private FOUserAgent userAgent;
     
+    private boolean used = false;
+    
     /**
      * FOTreeBuilder constructor
      * @param outputFormat the MIME type of the output format to use (ex. "application/pdf").
@@ -143,6 +147,11 @@ public class FOTreeBuilder extends DefaultHandler {
      * @see org.xml.sax.ContentHandler#startDocument()
      */
     public void startDocument() throws SAXException {
+        if (used) {
+            throw new IllegalStateException("FOTreeBuilder (and the Fop class) cannot be reused."
+                    + " Please instantiate a new instance.");
+        }
+        used = true;
         rootFObj = null;    // allows FOTreeBuilder to be reused
         if (log.isDebugEnabled()) {
             log.debug("Building formatting object tree");
@@ -300,14 +309,5 @@ public class FOTreeBuilder extends DefaultHandler {
         }
     }
     
-    /**
-     * Resets this object for another run.
-     */
-    public void reset() {
-        currentFObj = null;
-        rootFObj = null;
-        foEventHandler = null;
-    }
-
 }