Allow configuration of the exception class used when conflicts arise at UnitOfWork commit time to enable clients to provide custom/advanced/specific exceptions without having to do a bunch of encapsulation.

pom.xml

@@ -5,7 +5,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>net.helenus</groupId>
     <artifactId>helenus-core</artifactId>
-    <version>2.0.30-SNAPSHOT</version>
+    <version>2.0.31-SNAPSHOT</version>
     <packaging>jar</packaging>
 
     <name>helenus</name>

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

@@ -75,6 +75,7 @@ public final class HelenusSession extends AbstractSessionOperations implements C
           Executor executor,
           boolean dropSchemaOnClose,
           ConsistencyLevel consistencyLevel,
+          Class<? extends Exception> conflictExceptionClass,
           MetricRegistry metricRegistry,
           Tracer tracer) {
     this.session = session;
@@ -88,6 +89,7 @@ public final class HelenusSession extends AbstractSessionOperations implements C
     this.executor = executor;
     this.dropSchemaOnClose = dropSchemaOnClose;
     this.defaultConsistencyLevel = consistencyLevel;
+    UnitOfWork.conflictExceptionClass = conflictExceptionClass;
     this.metricRegistry = metricRegistry;
     this.zipkinTracer = tracer;
 

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

@@ -43,6 +43,7 @@ public final class SessionInitializer extends AbstractSessionOperations {
   private Tracer zipkinTracer;
   private PrintStream printStream = System.out;
   private Executor executor = MoreExecutors.directExecutor();
+  private Class<? extends Exception> conflictingUnitOfWorkClass = ConflictingUnitOfWorkException.class;
 
   private SessionRepositoryBuilder sessionRepository;
 
@@ -110,6 +111,11 @@ public final class SessionInitializer extends AbstractSessionOperations {
     return this;
   }
 
+  public SessionInitializer setConflictingUnitOfWorkException(Class<? extends Exception> e) {
+    this.conflictingUnitOfWorkClass = e;
+    return this;
+  }
+
   public SessionInitializer consistencyLevel(ConsistencyLevel consistencyLevel) {
     this.consistencyLevel = consistencyLevel;
     return this;
@@ -235,6 +241,7 @@ public final class SessionInitializer extends AbstractSessionOperations {
         executor,
         autoDdl == AutoDdl.CREATE_DROP,
         consistencyLevel,
+        conflictingUnitOfWorkClass,
         metricRegistry,
         zipkinTracer);
   }

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

@@ -9,6 +9,7 @@ import java.util.*;
 
 /** Encapsulates the concept of a "transaction" as a unit-of-work. */
 public class UnitOfWork implements AutoCloseable {
+  protected static Class<? extends Exception>conflictExceptionClass = ConflictingUnitOfWorkException.class;
   private final List<UnitOfWork> nested = new ArrayList<>();
   private final HelenusSession session;
   private final UnitOfWork parent;
@@ -74,7 +75,7 @@ public class UnitOfWork implements AutoCloseable {
    * @return a function from which to chain work that only happens when commit is successful
    * @throws ConflictingUnitOfWorkException when the work overlaps with other concurrent writers.
    */
-  public PostCommitFunction<Void, Void> commit() throws ConflictingUnitOfWorkException {
+  public PostCommitFunction<Void, Void> commit() throws Exception {
     // All nested UnitOfWork should be committed (not aborted) before calls to commit, check.
     boolean canCommit = true;
     TreeTraverser<UnitOfWork> traverser = TreeTraverser.using(node -> node::getChildNodes);
@@ -120,6 +121,10 @@ public class UnitOfWork implements AutoCloseable {
         return new PostCommitFunction(this, null);
       }
     }
+    // else {
+    // Constructor<?> ctor = clazz.getConstructor(conflictExceptionClass);
+    // Object object = ctor.newInstance(new Object[] { String message });
+    // }
     return new PostCommitFunction(this, postCommit);
   }