[Scripting] Add 'nashorn.global' object to unstored keys. Also add a method to...

[Scripting] Add 'nashorn.global' object to unstored keys. Also add a method to add new keys at runtime.

modules/activiti-engine/src/main/java/org/activiti/engine/impl/scripting/ScriptBindings.java

@@ -32,18 +32,18 @@ import org.activiti.engine.delegate.VariableScope;
 public class ScriptBindings implements Bindings {
 
   /**
-   * The script engine implementations put some key/value pairs into the binding. This list contains those keys, such that they wouldn't be stored as process variable.
+   * The script engine implementations put some key/value pairs into the binding. 
+   * This list contains those keys, such that they wouldn't be stored as process variable.
    * 
    * This list contains the keywords for JUEL, Javascript and Groovy.
    */
-  protected static final Set<String> UNSTORED_KEYS = new HashSet<String>(Arrays.asList("out", "out:print", "lang:import", "context", "elcontext", "print", "println"));
+  protected static final Set<String> UNSTORED_KEYS = 
+    new HashSet<String>(Arrays.asList("out", "out:print", "lang:import", "context", "elcontext", "print", "println", "nashorn.global"));
 
   protected List<Resolver> scriptResolvers;
   protected VariableScope variableScope;
   protected Bindings defaultBindings;
-  protected boolean storeScriptVariables = true; // By default everything is
-                                                 // stored (backwards
-                                                 // compatibility)
+  protected boolean storeScriptVariables = true; // By default everything is stored (backwards compatibility)
 
   public ScriptBindings(List<Resolver> scriptResolvers, VariableScope variableScope) {
     this.scriptResolvers = scriptResolvers;
@@ -124,4 +124,9 @@ public class ScriptBindings implements Bindings {
   public boolean isEmpty() {
     throw new UnsupportedOperationException();
   }
+  
+  public void addUnstoredKey(String unstoredKey) {
+  	UNSTORED_KEYS.add(unstoredKey);
+  }
+  
 }