This patch implements a pluggable LayoutManagers system, according

to the ideas of Finn Bock and his patch in bug 30500.

Created a LayoutManagerMaker interface, with method
makeLayoutManagers(FONode, List), and two convenience methods on top
of it.

Created an implementation: LayoutManagerMapping. This is along the
pattern of FOElementMapping. It creates a Map from FObj class to Maker
objects. There are many static inner classes which are subclasses of
Maker. Each subclass implements its own version of the make method.

FOUserAgent has a setter and getter for
LayoutManagerMakerOverride. AreaTreeHandler creates a
LayoutManagerMaker, taking the user's override into account, using
LayoutManagerMapping as the default. It has a get method for it.

The LayoutManager interface has a get method for the AreaTreeHandler
object, a reference to which is held in PageSequenceLM, the top of the
LM tree.


git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@198208 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 23 insertions, 2 deletions

diff --git a/src/java/org/apache/fop/area/AreaTreeHandler.java b/src/java/org/apache/fop/area/AreaTreeHandler.java
index df60e0cbb..fe0972da9 100644
--- a/src/java/org/apache/fop/area/AreaTreeHandler.java
+++ b/src/java/org/apache/fop/area/AreaTreeHandler.java
@@ -40,6 +40,8 @@ import org.apache.fop.fo.extensions.Bookmarks;
 import org.apache.fop.fo.pagination.PageSequence;
 import org.apache.fop.fo.pagination.Root;
 import org.apache.fop.layoutmgr.PageSequenceLayoutManager;
+import org.apache.fop.layoutmgr.LayoutManagerMaker;
+import org.apache.fop.layoutmgr.LayoutManagerMapping;
 
 /**
  * Area tree handler for formatting objects.
@@ -72,6 +74,9 @@ public class AreaTreeHandler extends FOEventHandler {
     // time used in rendering (for statistics)
     private long startTime;
 
+    // the LayoutManager maker
+    private LayoutManagerMaker lmMaker;
+
     // count of number of pages rendered
     private int pageCount;
 
@@ -106,6 +111,11 @@ public class AreaTreeHandler extends FOEventHandler {
         model = new RenderPagesModel(userAgent, renderType, fontInfo,
             stream);
             
+        lmMaker = userAgent.getLayoutManagerMakerOverride();
+        if (lmMaker == null) {
+            lmMaker = new LayoutManagerMapping();
+        }
+
         outputStatistics = log.isDebugEnabled();
 
         if (outputStatistics) {
@@ -123,6 +133,15 @@ public class AreaTreeHandler extends FOEventHandler {
     }
 
     /**
+     * Get the LayoutManager maker for this area tree.
+     *
+     * @return LayoutManagerMaker the LayoutManager maker being used for this area tree
+     */
+    public LayoutManagerMaker getLayoutManagerMaker() {
+        return lmMaker;
+    }
+
+    /**
      * Tie a PageViewport with an ID found on a child area of the PV.
      * Note that an area with a given ID may be on more than one PV, hence
      * an ID may have more than one PV associated with it.
@@ -210,8 +229,10 @@ public class AreaTreeHandler extends FOEventHandler {
 
         // If no main flow, nothing to layout!
         if (pageSequence.getMainFlow() != null) {
-            PageSequenceLayoutManager pageSLM 
-                = new PageSequenceLayoutManager(this, pageSequence);
+            PageSequenceLayoutManager pageSLM =
+                (PageSequenceLayoutManager)
+                getLayoutManagerMaker().makeLayoutManager(pageSequence);
+            pageSLM.setAreaTreeHandler(this);
             pageSLM.activateLayout();
         }
     }