Migrate documentation to Antora

Issue #4422

spring-batch-docs/modules/ROOT/pages/step/chunk-oriented-processing.adoc

@@ -0,0 +1,60 @@
+[[chunkOrientedProcessing]]
+= Chunk-oriented Processing
+
+Spring Batch uses a "`chunk-oriented`" processing style in its most common
+implementation. Chunk oriented processing refers to reading the data one at a time and
+creating 'chunks' that are written out within a transaction boundary. Once the number of
+items read equals the commit interval, the entire chunk is written out by the
+`ItemWriter`, and then the transaction is committed. The following image shows the
+process:
+
+.Chunk-oriented Processing
+image::chunk-oriented-processing.png[Chunk Oriented Processing, scaledwidth="60%"]
+
+The following pseudo code shows the same concepts in a simplified form:
+
+[source, java]
+----
+List items = new Arraylist();
+for(int i = 0; i < commitInterval; i++){
+    Object item = itemReader.read();
+    if (item != null) {
+        items.add(item);
+    }
+}
+itemWriter.write(items);
+----
+
+You can also configure a chunk-oriented step with an optional `ItemProcessor`
+to process items before passing them to the `ItemWriter`. The following image
+shows the process when an `ItemProcessor` is registered in the step:
+
+.Chunk-oriented Processing with Item Processor
+image::chunk-oriented-processing-with-item-processor.png[Chunk Oriented Processing With Item Processor, scaledwidth="60%"]
+
+The following pseudo code shows how this is implemented in a simplified form:
+
+[source, java]
+----
+List items = new Arraylist();
+for(int i = 0; i < commitInterval; i++){
+    Object item = itemReader.read();
+    if (item != null) {
+        items.add(item);
+    }
+}
+
+List processedItems = new Arraylist();
+for(Object item: items){
+    Object processedItem = itemProcessor.process(item);
+    if (processedItem != null) {
+        processedItems.add(processedItem);
+    }
+}
+
+itemWriter.write(processedItems);
+----
+
+For more details about item processors and their use cases, see the
+xref:processor.adoc[Item processing] section.
+