io.debezium.relational

Class TableSchemaBuilder

java.lang.Object

io.debezium.relational.TableSchemaBuilder

@ThreadSafe
 @Immutable
public class TableSchemaBuilder
extends Object

Builder that constructs TableSchema instances for Table definitions.

This builder is responsible for mapping table columns to fields in Kafka Connect Schemas, and this is necessarily dependent upon the database's supported types. Although mappings are defined for standard types, this class may need to be subclassed for each DBMS to add support for DBMS-specific types by overriding any of the "add*Field" methods.

See the Java SE Mapping SQL and Java Types for details about how JDBC types map to Java value types.

Author:

Randall Hauch

Field Summary

Fields

Modifier and Type	Field and Description
private static org.slf4j.Logger	LOGGER
private Function<String,String>	schemaNameValidator
private ValueConverterProvider	valueConverterProvider

Constructor Summary

Constructors

Constructor and Description
TableSchemaBuilder(ValueConverterProvider valueConverterProvider, Function<String,String> schemaNameValidator) Create a new instance of the builder.

Method Summary

Modifier and Type	Method and Description
protected void	addField(org.apache.kafka.connect.data.SchemaBuilder builder, Column column, ColumnMapper mapper) Add to the supplied SchemaBuilder a field for the column with the given information.
protected ValueConverter[]	convertersForColumns(org.apache.kafka.connect.data.Schema schema, TableId tableId, List<Column> columns, Predicate<ColumnId> filter, ColumnMappers mappers) Obtain the array of converters for each column in a row.
TableSchema	create(ResultSet resultSet, String name) Create a TableSchema from the given JDBC ResultSet.
TableSchema	create(String schemaPrefix, Table table) Create a TableSchema from the given table definition.
TableSchema	create(String schemaPrefix, Table table, Predicate<ColumnId> filter, ColumnMappers mappers) Create a TableSchema from the given table definition.
protected Function<Object[],Object>	createKeyGenerator(org.apache.kafka.connect.data.Schema schema, TableId columnSetName, List<Column> columns) Creates the function that produces a Kafka Connect key object for a row of data.
protected ValueConverter	createValueConverterFor(Column column, org.apache.kafka.connect.data.Field fieldDefn) Create a ValueConverter that can be used to convert row values for the given column into the Kafka Connect value object described by the field definition.
protected Function<Object[],org.apache.kafka.connect.data.Struct>	createValueGenerator(org.apache.kafka.connect.data.Schema schema, TableId tableId, List<Column> columns, Predicate<ColumnId> filter, ColumnMappers mappers) Creates the function that produces a Kafka Connect value object for a row of data.
protected org.apache.kafka.connect.data.Field[]	fieldsForColumns(org.apache.kafka.connect.data.Schema schema, List<Column> columns)
protected int[]	indexesForColumns(List<Column> columns)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOGGER

private static final org.slf4j.Logger LOGGER

schemaNameValidator

private final Function<String,String> schemaNameValidator

valueConverterProvider

private final ValueConverterProvider valueConverterProvider

Constructor Detail

TableSchemaBuilder

public TableSchemaBuilder(ValueConverterProvider valueConverterProvider,
                          Function<String,String> schemaNameValidator)

Create a new instance of the builder.

Parameters:

valueConverterProvider - the provider for obtaining ValueConverters and SchemaBuilders; may not be null

schemaNameValidator - the validation function for schema names; may not be null

Method Detail

create

public TableSchema create(ResultSet resultSet,
                          String name)
                   throws SQLException

Create a TableSchema from the given JDBC ResultSet. The resulting TableSchema will have no primary key, and its TableSchema.valueSchema() will contain fields for each column in the result set.

Parameters:

resultSet - the result set for a query; may not be null

name - the name of the value schema; may not be null

Returns:

the table schema that can be used for sending rows of data for this table to Kafka Connect; never null

Throws:

SQLException - if an error occurs while using the result set's metadata

create

public TableSchema create(String schemaPrefix,
                          Table table)

Create a TableSchema from the given table definition. The resulting TableSchema will have a key schema that contains all of the columns that make up the table's primary key, and a value schema that contains only those columns that are not in the table's primary key.

This is equivalent to calling create(table,false).

Parameters:

schemaPrefix - the prefix added to the table identifier to construct the schema names; may be null if there is no prefix

table - the table definition; may not be null

Returns:

the table schema that can be used for sending rows of data for this table to Kafka Connect; never null

create

public TableSchema create(String schemaPrefix,
                          Table table,
                          Predicate<ColumnId> filter,
                          ColumnMappers mappers)

Create a TableSchema from the given table definition. The resulting TableSchema will have a key schema that contains all of the columns that make up the table's primary key, and a value schema that contains only those columns that are not in the table's primary key.

This is equivalent to calling create(table,false).

Parameters:

schemaPrefix - the prefix added to the table identifier to construct the schema names; may be null if there is no prefix

table - the table definition; may not be null

filter - the filter that specifies whether columns in the table should be included; may be null if all columns are to be included

mappers - the mapping functions for columns; may be null if none of the columns are to be mapped to different values

Returns:

the table schema that can be used for sending rows of data for this table to Kafka Connect; never null

createKeyGenerator

protected Function<Object[],Object> createKeyGenerator(org.apache.kafka.connect.data.Schema schema,
                                                       TableId columnSetName,
                                                       List<Column> columns)

Creates the function that produces a Kafka Connect key object for a row of data.

Parameters:

schema - the Kafka Connect schema for the key; may be null if there is no known schema, in which case the generator will be null

columnSetName - the name for the set of columns, used in error messages; may not be null

columns - the column definitions for the table that defines the row; may not be null

Returns:

the key-generating function, or null if there is no key schema

createValueGenerator

protected Function<Object[],org.apache.kafka.connect.data.Struct> createValueGenerator(org.apache.kafka.connect.data.Schema schema,
                                                                                       TableId tableId,
                                                                                       List<Column> columns,
                                                                                       Predicate<ColumnId> filter,
                                                                                       ColumnMappers mappers)

Creates the function that produces a Kafka Connect value object for a row of data.

Parameters:

schema - the Kafka Connect schema for the value; may be null if there is no known schema, in which case the generator will be null

tableId - the table identifier; may not be null

columns - the column definitions for the table that defines the row; may not be null

filter - the filter that specifies whether columns in the table should be included; may be null if all columns are to be included

mappers - the mapping functions for columns; may be null if none of the columns are to be mapped to different values

Returns:

the value-generating function, or null if there is no value schema

indexesForColumns

protected int[] indexesForColumns(List<Column> columns)

fieldsForColumns

protected org.apache.kafka.connect.data.Field[] fieldsForColumns(org.apache.kafka.connect.data.Schema schema,
                                                                 List<Column> columns)

convertersForColumns

protected ValueConverter[] convertersForColumns(org.apache.kafka.connect.data.Schema schema,
                                                TableId tableId,
                                                List<Column> columns,
                                                Predicate<ColumnId> filter,
                                                ColumnMappers mappers)

Obtain the array of converters for each column in a row. A converter might be null if the column is not be included in the records.

Parameters:

schema - the schema; may not be null

tableId - the identifier of the table that contains the columns

columns - the columns in the row; may not be null

filter - the filter that specifies whether columns in the table should be included; may be null if all columns are to be included

mappers - the mapping functions for columns; may be null if none of the columns are to be mapped to different values

Returns:

the converters for each column in the rows; never null

addField

protected void addField(org.apache.kafka.connect.data.SchemaBuilder builder,
                        Column column,
                        ColumnMapper mapper)

Add to the supplied SchemaBuilder a field for the column with the given information.

Parameters:

builder - the schema builder; never null

column - the column definition

mapper - the mapping function for the column; may be null if the columns is not to be mapped to different values

createValueConverterFor

protected ValueConverter createValueConverterFor(Column column,
                                                 org.apache.kafka.connect.data.Field fieldDefn)

Create a ValueConverter that can be used to convert row values for the given column into the Kafka Connect value object described by the field definition. This uses the supplied ValueConverterProvider object.

Parameters:

column - the column describing the input values; never null

fieldDefn - the definition for the field in a Kafka Connect Schema describing the output of the function; never null

Returns:

the value conversion function; may not be null