Added compiler for aggregation functions.

Added the necessary parts for compiling a user-defined aggregation function
from a java class.

community/kernel/src/main/java/org/neo4j/kernel/api/proc/CallableUserAggregationFunction.java

@@ -24,13 +24,13 @@
 public interface CallableUserAggregationFunction
 {
     UserFunctionSignature signature();
-    Aggregator create( Context ctx );
+    Aggregator create( Context ctx ) throws ProcedureException;
 
     interface Aggregator
     {
         void update( Object[] input ) throws ProcedureException;
 
-        Object result();
+        Object result() throws ProcedureException;
     }
 
 

community/kernel/src/main/java/org/neo4j/kernel/impl/proc/FieldInjections.java

@@ -33,25 +33,25 @@
 /**
  * Injects annotated fields with appropriate values.
  */
-public class FieldInjections
+class FieldInjections
 {
     private final ComponentRegistry components;
 
-    public FieldInjections( ComponentRegistry components )
+    FieldInjections( ComponentRegistry components )
     {
         this.components = components;
     }
 
     /**
      * On calling apply, injects the `value` for the field `field` on the provided `object`.
      */
-    public static class FieldSetter
+    static class FieldSetter
     {
         private final Field field;
         private final MethodHandle setter;
         private final ComponentRegistry.Provider<?> provider;
 
-        public FieldSetter( Field field, MethodHandle setter, ComponentRegistry.Provider<?> provider )
+        FieldSetter( Field field, MethodHandle setter, ComponentRegistry.Provider<?> provider )
         {
             this.field = field;
             this.setter = setter;
@@ -79,7 +79,7 @@ void apply( org.neo4j.kernel.api.proc.Context ctx, Object object ) throws Proced
      * @return A list of `FieldSetters`
      * @throws ProcedureException if the type of the injected field does not match what has been registered.
      */
-    public List<FieldSetter> setters( Class<?> cls ) throws ProcedureException
+    List<FieldSetter> setters( Class<?> cls ) throws ProcedureException
     {
         List<FieldSetter> setters = new LinkedList<>();
         Class<?> currentClass = cls;