Package com.hazelcast.enterprise.jet.cdc

Interface RecordPart

public interface RecordPart
Represents the top-level component of a ChangeRecord, such as the key or the value. Since these components are JSON expressions, this is actually a generic wrapper around a JSON expression. Contains various methods for retrieving component values or for mapping itself to data objects.
Since:
5.5

  • Method Summary

    Modifier and Type
    Method
    Description
    String
    toJson()
    Returns the raw JSON string that this object wraps.
    Map<String,Object>
    toMap()
    Presents a parsed form of the underlying JSON message as a Map.
    <T> T
    toObject(Class<T> clazz)
    Maps the entire element to an instance of the specified class.

  • Method Details

    • toObject

      @Nonnull <T> T toObject(@Nonnull Class<T> clazz) throws ParsingException
      Maps the entire element to an instance of the specified class.

      Parsing is based on Jackson with annotation support, so the supplied class can be annotated accordingly.

      Note: there is a neat trick for converting types during object mapping. Let's say we have a birth_date column in a table of type DATE and we want to map it to a field named birthDate in our row object, of type LocalDate. We would write code like this: 

        
  public LocalDate birthDate;

  public void setBirthDate(long dateInEpochDays) {
      this.birthDate = dateInEpochDays == 0 ? null : LocalDate.ofEpochDay(dateInEpochDays);
  }
      The things to note here is that by specifying a setter and giving it the input parameter type of long we force the object mapping to interpret the column value as a long (as opposed to Date). Then we can take care of null handling and converting to whatever desired type ourselves.
      Returns:
      object of type T, obtained as the result of the mapping
      Throws:
      ParsingException - if the mapping fails to produce a result

    • toMap

      @Nonnull Map<String,Object> toMap() throws ParsingException
      Presents a parsed form of the underlying JSON message as a Map. The keys are the top-level fields from the JSON and the values can range from simple strings, numbers, collections and sub-maps.

      Parsing is based on Jackson, you can refer to its documentation for more details.

      Returns:
      Map representation of the JSON data
      Throws:
      ParsingException - if the underlying JSON message fails to parse

    • toJson

      @Nonnull String toJson()
      Returns the raw JSON string that this object wraps. You can use it if parsing is failing for some reason (for example on some untested DB-connector version combination).