Fixed JSON Bug for some plans.

Signed-off-by: Robert Metzger <[email protected]>

This closes apache#23.

stratosphere-compiler/src/main/java/eu/stratosphere/compiler/plandump/PlanJSONDumpGenerator.java

@@ -132,19 +132,22 @@ private void compilePlanToJSON(List<DumpableNode<?>> nodes, PrintWriter writer)
  writer.println("\n\t]\n}");
  }
 
- private void visit(DumpableNode<?> node, PrintWriter writer, boolean first) {
+ private boolean visit(DumpableNode<?> node, PrintWriter writer, boolean first) {
  // check for duplicate traversal
  if (this.nodeIds.containsKey(node)) {
- return;
+ return false;
  }
 
  // assign an id first
  this.nodeIds.put(node, this.nodeCnt++);
 
  // then recurse
  for (DumpableNode<?> child : node.getPredecessors()) {
- visit(child, writer, first);
- first = false;
+ //This is important, because when the node was already in the graph it is not allowed
+ //to set first to false!
+ if (visit(child, writer, first)) {
+ first = false;
+ };
  }
 
  // check if this node should be skipped from the dump
@@ -153,7 +156,7 @@ private void visit(DumpableNode<?> node, PrintWriter writer, boolean first) {
  // ------------------ dump after the ascend ---------------------
  // start a new node and output node id
  if (!first) {
- writer.print(",\n");
+ writer.print(",\n"); 
  }
  // open the node
  writer.print("\t{\n");
@@ -385,7 +388,7 @@ private void visit(DumpableNode<?> node, PrintWriter writer, boolean first) {
  if (p == null) {
  // finish node
  writer.print("\n\t}");
- return;
+ return true;
  }
  // local strategy
  String locString = null;
@@ -579,6 +582,7 @@ private void visit(DumpableNode<?> node, PrintWriter writer, boolean first) {
 
  // finish node
  writer.print("\n\t}");
+ return true;
  }
 
  private void addProperty(PrintWriter writer, String name, String value, boolean first) {