Interface TableFactory<T extends Table>

  • Type Parameters:
    T - Sub-type of table created by this factory
    All Known Implementing Classes:
    CsvStreamTableFactory, CsvTableFactory, DruidTableFactory, KafkaTableFactory, PigTableFactory, PreferredAlbumsTableFactory, PreferredGenresTableFactory

    public interface TableFactory<T extends Table>
    Factory for Table objects.

    A table factory allows you to include custom tables in a model file. For example, here is a model that contains a custom table that generates a range of integers.

    {
       version: '1.0',
       defaultSchema: 'MATH',
       schemas: [
         {
           name: 'MATH',
           tables: [
             {
               name: 'INTEGERS',
               type: 'custom',
               factory: 'com.acme.IntegerTable',
               operand: {
                 start: 3,
                 end: 7,
                 column: 'N'
               }
             }
           ]
         }
       ]
     }

    Given that schema, the query

    SELECT * FROM math.integers

    returns

     +---+
     | N |
     +---+
     | 3 |
     | 4 |
     | 5 |
     | 6 |
     +---+
     

    A class that implements TableFactory specified in a schema must have a public default constructor.

    • Method Detail

      • create

        T create​(SchemaPlus schema,
                 java.lang.String name,
                 java.util.Map<java.lang.String,​java.lang.Object> operand,
                 RelDataType rowType)
        Creates a Table.
        Parameters:
        schema - Schema this table belongs to
        name - Name of this table
        operand - The "operand" JSON property
        rowType - Row type. Specified if the "columns" JSON property.