Add isDone() method on UnitOfWork.

src/main/java/net/helenus/core/AbstractUnitOfWork.java

@@ -312,7 +312,11 @@ public abstract class AbstractUnitOfWork<E extends Exception>
    * @return a function from which to chain work that only happens when commit is successful
    * @throws E when the work overlaps with other concurrent writers.
    */
-  public PostCommitFunction<Void, Void> commit() throws E, TimeoutException {
+  public synchronized PostCommitFunction<Void, Void> commit() throws E, TimeoutException {
+
+    if (isDone()) {
+      return new PostCommitFunction(this, null, null, false);
+    }
 
     // Only the outer-most UOW batches statements for commit time, execute them.
     if (batch != null) {
@@ -411,7 +415,7 @@ public abstract class AbstractUnitOfWork<E extends Exception>
 
   /* Explicitly discard the work and mark it as as such in the log. */
   public synchronized void abort() {
-    if (!aborted) {
+    if (!isDone()) {
       aborted = true;
 
       // Spoil any pending futures created within the context of this unit of work.
@@ -458,6 +462,10 @@ public abstract class AbstractUnitOfWork<E extends Exception>
             });
   }
 
+  public boolean isDone() {
+      return aborted || committed;
+  }
+
   public String describeConflicts() {
     return "it's complex...";
   }

src/main/java/net/helenus/core/UnitOfWork.java

@@ -53,6 +53,8 @@ public interface UnitOfWork<X extends Exception> extends AutoCloseable {
 
   boolean hasCommitted();
 
+  boolean isDone();
+
   long committedAt();
 
   void batch(AbstractOperation operation);