Package com.pushtechnology.diffusion.datatype.recordv2

Interface RecordV2Delta

public interface RecordV2Delta
RecordV2 structural delta.

A RecordV2Delta describes the differences between two RecordV2 values. Unlike a binary delta, a structural delta can be queried to determine its effect. The changes(com.pushtechnology.diffusion.datatype.recordv2.schema.Schema) method provides details of which values have changed.

An instance can be created from two RecordV2 values using RecordV2.diff(RecordV2).

RecordV2Deltas are useful for identifying small changes to complex RecordV2 values. Here's any example of how to use this class to filter interesting changes in a ValueStream. 

 public class ExampleStream implements ValueStream<RecordV2> {
   public void onValue(String topicPath, RecordV2 oldValue, RecordV2 newValue) {
     RecordV2Delta delta = newValue.diff(oldValue);

     for (Change change : delta.changes(schema)) {
         if (change.fieldName().equals("address") {
             processAddress(newValue);
         }
     }
   }

   // ...
 }
Since:
6.0
Author:
DiffusionData Limited

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Interface
    Description
    static interface 
    RecordV2Delta.Change
    Represents a single change between one record value and another.

  • Method Summary

    Modifier and Type
    Method
    Description
    List<RecordV2Delta.Change>
    changes(Schema schema)
    Returns a list of the changes represented by the delta with reference to a specified schema.

  • Method Details

    • changes

      List<RecordV2Delta.Change> changes(Schema schema)
      Returns a list of the changes represented by the delta with reference to a specified schema.

      The schema supplied must comply with the data format of the delta. No validation takes place, so if the schema does not match the data then the results may be unpredictable.

      Parameters:
      schema - the schema
      Returns:
      the list of changes