From 9acb5772b411f485f0211718f79bf7479cb4cb1f Mon Sep 17 00:00:00 2001
From: Lukas Eder <lukas.eder@gmail.com>
Date: Wed, 22 Jul 2020 16:26:32 +0200
Subject: [PATCH] [jOOQ/jOOQ#4941] Add LoaderListenerStep.onRowStart() for
 preprocessing input data

---
 .../src/main/java/org/jooq/LoaderContext.java | 13 ++++++
 .../java/org/jooq/LoaderListenerStep.java     | 20 ++++++++-
 .../main/java/org/jooq/LoaderRowListener.java |  2 +-
 .../main/java/org/jooq/impl/LoaderImpl.java   | 43 ++++++++++++++++---
 4 files changed, 70 insertions(+), 8 deletions(-)

diff --git a/jOOQ/src/main/java/org/jooq/LoaderContext.java b/jOOQ/src/main/java/org/jooq/LoaderContext.java
index cc36da814a..40fdc55f8a 100644
--- a/jOOQ/src/main/java/org/jooq/LoaderContext.java
+++ b/jOOQ/src/main/java/org/jooq/LoaderContext.java
@@ -49,6 +49,19 @@ import org.jetbrains.annotations.NotNull;
  */
 public interface LoaderContext {
 
+    /**
+     * Override the row that will be processed. Changing it has now effect on
+     * the {@link LoaderListenerStep#onRowEnd(LoaderRowListener)} event.
+     */
+    @NotNull
+    LoaderContext row(Object[] row);
+
+    /**
+     * The row that will be or has been processed.
+     */
+    @NotNull
+    Object[] row();
+
     /**
      * A list of errors that might have happened during the load.
      */
diff --git a/jOOQ/src/main/java/org/jooq/LoaderListenerStep.java b/jOOQ/src/main/java/org/jooq/LoaderListenerStep.java
index 31288fc5a9..460bd4a21c 100644
--- a/jOOQ/src/main/java/org/jooq/LoaderListenerStep.java
+++ b/jOOQ/src/main/java/org/jooq/LoaderListenerStep.java
@@ -37,7 +37,7 @@
  */
 package org.jooq;
 
-import org.jetbrains.annotations.*;
+import org.jetbrains.annotations.NotNull;
 
 
 /**
@@ -70,8 +70,26 @@ public interface LoaderListenerStep<R extends Record> extends LoaderLoadStep<R>
 
     /**
      * Specify a listener that is invoked whenever a row has been processed.
+     *
+     * @deprecated - 3.14.0 - [#4941] - Use {@link #onRowEnd(LoaderRowListener)}
+     *             instead.
      */
+    @Deprecated
     @NotNull
     @Support
     LoaderLoadStep<R> onRow(LoaderRowListener listener);
+
+    /**
+     * Specify a listener that is invoked before a row is processed.
+     */
+    @NotNull
+    @Support
+    LoaderLoadStep<R> onRowStart(LoaderRowListener listener);
+
+    /**
+     * Specify a listener that is invoked after a row has been processed.
+     */
+    @NotNull
+    @Support
+    LoaderLoadStep<R> onRowEnd(LoaderRowListener listener);
 }
diff --git a/jOOQ/src/main/java/org/jooq/LoaderRowListener.java b/jOOQ/src/main/java/org/jooq/LoaderRowListener.java
index 9b50a7a203..017611466e 100644
--- a/jOOQ/src/main/java/org/jooq/LoaderRowListener.java
+++ b/jOOQ/src/main/java/org/jooq/LoaderRowListener.java
@@ -47,7 +47,7 @@ package org.jooq;
 public interface LoaderRowListener {
 
     /**
-     * A row has been processed by the {@link Loader}
+     * A row will be or has been processed by the {@link Loader}.
      */
     void row(LoaderContext ctx);
 }
diff --git a/jOOQ/src/main/java/org/jooq/impl/LoaderImpl.java b/jOOQ/src/main/java/org/jooq/impl/LoaderImpl.java
index db4489896e..3d800a1c4a 100644
--- a/jOOQ/src/main/java/org/jooq/impl/LoaderImpl.java
+++ b/jOOQ/src/main/java/org/jooq/impl/LoaderImpl.java
@@ -178,8 +178,9 @@ final class LoaderImpl<R extends Record> implements
 
     // Result data
     // -----------
-    private LoaderRowListener            listener;
-    private LoaderContext                result                           = new DefaultLoaderContext();
+    private LoaderRowListener            onRowStart;
+    private LoaderRowListener            onRowEnd;
+    private LoaderContext                rowCtx                           = new DefaultLoaderContext();
     private int                          ignored;
     private int                          processed;
     private int                          stored;
@@ -645,7 +646,18 @@ final class LoaderImpl<R extends Record> implements
 
     @Override
     public final LoaderImpl<R> onRow(LoaderRowListener l) {
-        listener = l;
+        return onRowEnd(l);
+    }
+
+    @Override
+    public final LoaderImpl<R> onRowStart(LoaderRowListener l) {
+        onRowStart = l;
+        return this;
+    }
+
+    @Override
+    public final LoaderImpl<R> onRowEnd(LoaderRowListener l) {
+        onRowEnd = l;
         return this;
     }
 
@@ -817,6 +829,12 @@ final class LoaderImpl<R extends Record> implements
                             if (fields[i].getType() == byte[].class && row[i] instanceof String)
                                 row[i] = DatatypeConverter.parseBase64Binary((String) row[i]);
 
+                    rowCtx.row(row);
+                    if (onRowStart != null) {
+                        onRowStart.row(rowCtx);
+                        row = rowCtx.row();
+                    }
+
                     // TODO: In batch mode, we can probably optimise this by not creating
                     // new statements every time, just to convert bind values to their
                     // appropriate target types. But beware of SQL dialects that tend to
@@ -916,8 +934,8 @@ final class LoaderImpl<R extends Record> implements
 
                 }
                 finally {
-                    if (listener != null)
-                        listener.row(result);
+                    if (onRowEnd != null)
+                        onRowEnd.row(rowCtx);
                 }
                 // rows:
             }
@@ -1037,10 +1055,23 @@ final class LoaderImpl<R extends Record> implements
 
     @Override
     public final LoaderContext result() {
-        return result;
+        return rowCtx;
     }
 
     private class DefaultLoaderContext implements LoaderContext {
+        Object[] row;
+
+        @Override
+        public final LoaderContext row(Object[] r) {
+            this.row = r;
+            return this;
+        }
+
+        @Override
+        public final Object[] row() {
+            return row;
+        }
+
         @Override
         public final List<LoaderError> errors() {
             return errors;