Added @PreConsumed annotation

components/camel-jpa/src/main/java/org/apache/camel/component/jpa/JpaConsumer.java

@@ -46,6 +46,7 @@ public class JpaConsumer extends ScheduledBatchPollingConsumer {
     private final TransactionStrategy template;
     private QueryFactory queryFactory;
     private DeleteHandler<Object> deleteHandler;
+    private DeleteHandler<Object> preConsumedMethod = null;
     private String query;
     private String namedQuery;
     private String nativeQuery;
@@ -122,7 +123,7 @@ public Object doInJpa(EntityManager entityManager) throws PersistenceException {
         return endpoint.getCamelContext().getTypeConverter().convertTo(int.class, messagePolled);
     }
 
-
+    
     public int processBatch(Queue<Object> exchanges) throws Exception {
         int total = exchanges.size();
 
@@ -146,8 +147,12 @@ public int processBatch(Queue<Object> exchanges) throws Exception {
 
             // update pending number of exchanges
             pendingExchanges = total - index - 1;
-
+            
             if (lockEntity(result, entityManager)) {
+                // Run the @PreConsumed callback - User supplied preprocessing
+                DeleteHandler<Object> preConsumed = getPreConsumedMethod();
+                preConsumed.deleteObject(entityManager, result);
+
                 // process the current exchange
                 LOG.debug("Processing exchange: {}", exchange);
                 getProcessor().process(exchange);
@@ -170,6 +175,45 @@ public JpaEndpoint getEndpoint() {
         return endpoint;
     }
 
+    public DeleteHandler<Object> getPreConsumedMethod() {
+        if (preConsumedMethod == null) {
+            // Look for @PreConsumed to allow custom callback before the Entity has been consumed
+            Class<?> entityType = getEndpoint().getEntityType();
+            if (entityType != null) {
+                // Inspect the method(s) annotated with @PreConsumed
+                List<Method> methods = ObjectHelper.findMethodsWithAnnotation(entityType, PreConsumed.class);
+                if (methods.size() > 1) {
+                    throw new IllegalStateException("Only one method can be annotated with the @PreConsumed annotation but found: " + methods);
+                } else if (methods.size() == 1) {
+                    // Inspect the parameters of the @PreConsumed method
+                    Class<?>[] parameters = methods.get(0).getParameterTypes();
+                    if (parameters.length != 0) {
+                        throw new IllegalStateException("@PreConsumed annotated method cannot have parameters!");
+                    }
+
+                    final Method method = methods.get(0);
+                    preConsumedMethod = new DeleteHandler<Object>() {
+                        @Override
+                        public void deleteObject(EntityManager entityManager, Object entityBean) {
+                            ObjectHelper.invokeMethod(method, entityBean);
+                        }
+                    };
+                } else {
+                    preConsumedMethod = new DeleteHandler<Object>() {
+                        @Override
+                        public void deleteObject(EntityManager entityManager, Object entityBean) {
+                            // Do nothing
+                        }
+                    };
+                }
+            } else {
+                throw new IllegalStateException("Jpa endpoint did not contain a defined entity type!");
+            }
+        }
+
+        return preConsumedMethod;
+    }
+
     public QueryFactory getQueryFactory() {
         if (queryFactory == null) {
             queryFactory = createQueryFactory();

components/camel-jpa/src/main/java/org/apache/camel/component/jpa/PreConsumed.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2013 The Apache Software Foundation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.camel.component.jpa;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * An annotation to mark a method to be invoked before an entity bean is processed and routed; so
+ * that it can be updated in such a way that the results are available to later nodes in the route.
+ * 
+ * @author R. Matt McCann [mccann.matt AT gmail.com]
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Target({ ElementType.METHOD })
+public @interface PreConsumed { }