Package com.clickhouse.client.api.data_formats

Interface JsonParser

All Superinterfaces:
AutoCloseable
public interface JsonParser extends AutoCloseable
Interface for JSON row processors.

Implementations are responsible for reading one JSON object per call from the underlying input stream and returning its fields as a Map keyed by column name.

Iteration-order contract

The reader infers its column schema from the keys of the first row, in iteration order, and uses that order to resolve 1-based column indexes for every subsequent row. Implementations must therefore return a Map that preserves the insertion order of the JSON keys as they appeared on the wire (e.g. LinkedHashMap); a hash-ordered HashMap is not acceptable because it destabilises index-based access.

The bundled JacksonJsonParserFactory (which produces LinkedHashMap via Jackson's Map.class default) and GsonJsonParserFactory (which produces LinkedTreeMap) both satisfy this contract. Custom implementations must take care not to regress it.

  • Method Summary

    Modifier and Type
    Method
    Description
    Map<String,Object>
    nextRow()
    Reads next row from the input stream.

    Methods inherited from interface java.lang.AutoCloseable

    close

  • Method Details

    • nextRow

      Map<String,Object> nextRow() throws Exception
      Reads next row from the input stream.

      The returned map must preserve the insertion order of the JSON keys as defined by the interface contract.

      Returns:
      map of column names to values, or null if no more rows
      Throws:
      Exception - if an error occurs during parsing