Session: How to Defer Commands

Commands can be deferred till saveChanges is called by using defer method in advanced session operations.
All of the operations will update teh session state appropriately after saveChanges is called.

Types of commands that can be deferred:

• PutCommandData
• DeleteCommandData
• DeletePrefixedCommandData
• PatchCommandData
• PutAttachmentCommandData
• DeleteAttachmentCommandData
• CopyAttachmentCommandData
• MoveAttachmentCommandData
• CountersBatchCommandData

Syntax

void defer(ICommandData command, ICommandData... commands);

void defer(ICommandData[] commands);

Example

Map<String, Object> value1 = new HashMap<>();
value1.put("Name", "My Product");
value1.put("Supplier", "suppliers/999-A");
value1.put("@metadata", Collections.singletonMap("@collection", "Users"));

PutCommandDataWithJson putCommand1 =
    new PutCommandDataWithJson("products/999-A",
        null,
        store.getConventions().getEntityMapper().valueToTree(value1));

HashMap<String, Object> value2 = new HashMap<>();
value2.put("Name", "My Product");
value2.put("Supplier", "suppliers/999-A");
value2.put("@metadata", Collections.singletonMap("@collection", "Suppliers"));

PutCommandDataWithJson putCommand2 =
    new PutCommandDataWithJson("suppliers/999-A",
        null,
        store.getConventions().getEntityMapper().valueToTree(value2));

DeleteCommandData command3 = new DeleteCommandData("products/1-A", null);

session.advanced().defer(putCommand1, putCommand2, command3);