Index: src/java/org/apache/wiki/workflow/AbstractStep.java
===================================================================
--- src/java/org/apache/wiki/workflow/AbstractStep.java	(revision 770483)
+++ src/java/org/apache/wiki/workflow/AbstractStep.java	(working copy)
@@ -112,10 +112,10 @@
     /**
      * {@inheritDoc}
      */
-    public final Collection<Outcome> getAvailableOutcomes()
+    public final Set<Outcome> getAvailableOutcomes()
     {
         Set<Outcome> outcomes = m_successors.keySet();
-        return Collections.unmodifiableCollection( outcomes );
+        return Collections.unmodifiableSet( outcomes );
     }
 
     /**
Index: src/java/org/apache/wiki/workflow/Step.java
===================================================================
--- src/java/org/apache/wiki/workflow/Step.java	(revision 770483)
+++ src/java/org/apache/wiki/workflow/Step.java	(working copy)
@@ -22,9 +22,9 @@
 
 import java.io.Serializable;
 import java.security.Principal;
-import java.util.Collection;
 import java.util.Date;
 import java.util.List;
+import java.util.Set;
 
 import org.apache.wiki.api.WikiException;
 
@@ -89,7 +89,7 @@
      * 
      * @return the set of outcomes
      */
-    public Collection<Outcome> getAvailableOutcomes();
+    public Set<Outcome> getAvailableOutcomes();
 
     /**
      * Returns a List of error strings generated by this Step. If this Step
Index: tests/java/org/apache/wiki/workflow/SimpleDecisionTest.java
===================================================================
--- tests/java/org/apache/wiki/workflow/SimpleDecisionTest.java	(revision 770483)
+++ tests/java/org/apache/wiki/workflow/SimpleDecisionTest.java	(working copy)
@@ -20,8 +20,8 @@
  */
 package org.apache.wiki.workflow;
 
-import java.util.Collection;
 import java.util.List;
+import java.util.Set;
 
 import org.apache.wiki.api.WikiException;
 import org.apache.wiki.auth.WikiPrincipal;
@@ -111,7 +111,7 @@
 
     public void testAvailableOutcomes()
     {
-        Collection<Outcome> outcomes = m_decision.getAvailableOutcomes();
+        Set<Outcome> outcomes = m_decision.getAvailableOutcomes();
         assertTrue(outcomes.contains(Outcome.DECISION_APPROVE));
         assertTrue(outcomes.contains(Outcome.DECISION_DENY));
         assertFalse(outcomes.contains(Outcome.DECISION_HOLD));
Index: tests/java/org/apache/wiki/workflow/TaskTest.java
===================================================================
--- tests/java/org/apache/wiki/workflow/TaskTest.java	(revision 770483)
+++ tests/java/org/apache/wiki/workflow/TaskTest.java	(working copy)
@@ -20,8 +20,8 @@
  */
 package org.apache.wiki.workflow;
 
-import java.util.Collection;
 import java.util.List;
+import java.util.Set;
 
 import org.apache.wiki.api.WikiException;
 import org.apache.wiki.auth.WikiPrincipal;
@@ -116,7 +116,7 @@
 
     public void testAvailableOutcomes()
     {
-        Collection<Outcome> outcomes = m_task.getAvailableOutcomes();
+        Set<Outcome> outcomes = m_task.getAvailableOutcomes();
         assertFalse(outcomes.contains(Outcome.DECISION_APPROVE));
         assertFalse(outcomes.contains(Outcome.DECISION_DENY));
         assertFalse(outcomes.contains(Outcome.DECISION_HOLD));