FOP-2596: NPE with changing ipd

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1736999 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 18 insertions, 9 deletions

diff --git a/fop-core/src/main/java/org/apache/fop/layoutmgr/AbstractBreaker.java b/fop-core/src/main/java/org/apache/fop/layoutmgr/AbstractBreaker.java
index d0594ce8a..cc598ff88 100644
--- a/fop-core/src/main/java/org/apache/fop/layoutmgr/AbstractBreaker.java
+++ b/fop-core/src/main/java/org/apache/fop/layoutmgr/AbstractBreaker.java
@@ -464,15 +464,7 @@ public abstract class AbstractBreaker {
         if (onLastPageAndIPDChanges && visitedBefore && this.originalRestartAtLM == null) {
             optimalBreak = null;
         }
-
-        int positionIndex = (optimalBreak != null) ? optimalBreak.position : start;
-        KnuthElement elementAtBreak = alg.getElement(positionIndex);
-        if (elementAtBreak.getPosition() == null) {
-            elementAtBreak = alg.getElement(0);
-        }
-        positionAtBreak = elementAtBreak.getPosition();
-        /* Retrieve the original position wrapped into this space position */
-        positionAtBreak = positionAtBreak.getPosition();
+        int positionIndex = findPositionIndex(optimalBreak, alg, start);
         if (ipdChangesOnNextPage || (positionAtBreak != null && positionAtBreak.getIndex() > -1)) {
             firstElementsForRestart = Collections.EMPTY_LIST;
             if (ipdChangesOnNextPage) {
@@ -542,6 +534,23 @@ public abstract class AbstractBreaker {
         return restartAtLM;
     }
 
+    private int findPositionIndex(KnuthNode optimalBreak, PageBreakingAlgorithm alg, int start) {
+        int positionIndex = (optimalBreak != null) ? optimalBreak.position : start;
+        for (int i = positionIndex; i < alg.par.size(); i++) {
+            KnuthElement elementAtBreak = alg.getElement(i);
+            if (elementAtBreak.getPosition() == null) {
+                elementAtBreak = alg.getElement(0);
+            }
+            positionAtBreak = elementAtBreak.getPosition();
+            /* Retrieve the original position wrapped into this space position */
+            positionAtBreak = positionAtBreak.getPosition();
+            if (positionAtBreak != null) {
+                return i;
+            }
+        }
+        return positionIndex;
+    }
+
     /**
      * Returns {@code true} if the given position or one of its descendants
      * corresponds to a non-restartable LM.