org.apache.kafka.connect.data

Class Values

java.lang.Object

org.apache.kafka.connect.data.Values

public class Values
extends Object

Utility for converting from one Connect value to a different form. This is useful when the caller expects a value of a particular type but is uncertain whether the actual value is one that isn't directly that type but can be converted into that type.

For example, a caller might expects a particular Header to contain an Schema.Type.INT64 value, when in fact that header contains a string representation of a 32-bit integer. Here, the caller can use the methods in this class to convert the value to the desired type:

     Header header = ...
     long value = Values.convertToLong(header.schema(), header.value());
 

This class is able to convert any value to a string representation as well as parse those string representations back into most of the types. The only exception is Struct values that require a schema and thus cannot be parsed from a simple string.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	Values.Parser
protected static class	Values.SchemaDetector

Constructor Summary

Constructors

Constructor and Description
Values()

Method Summary

Modifier and Type	Method and Description
protected static List<Object>	alignListEntriesWithSchema(Schema schema, List<Object> input)
protected static Map<Object,Object>	alignMapKeysAndValuesWithSchema(Schema mapSchema, Map<Object,Object> input)
protected static void	append(StringBuilder sb, Object value, boolean embedded)
protected static void	appendIterable(StringBuilder sb, Iterator<?> iter)
protected static double	asDouble(Object value, Schema schema, Throwable error) Convert the specified value with the desired floating point type.
protected static long	asLong(Object value, Schema fromSchema, Throwable error) Convert the specified value to the desired scalar value type.
protected static Schema	commonSchemaFor(Schema previous, SchemaAndValue latest)
protected static Object	convertTo(Schema toSchema, Schema fromSchema, Object value) Convert the value to the desired type.
static Boolean	convertToBoolean(Schema schema, Object value) Convert the specified value to an Schema.Type.BOOLEAN value.
static Byte	convertToByte(Schema schema, Object value) Convert the specified value to an Schema.Type.INT8 byte value.
static Date	convertToDate(Schema schema, Object value) Convert the specified value to an date value.
static BigDecimal	convertToDecimal(Schema schema, Object value, int scale) Convert the specified value to an decimal value.
static Double	convertToDouble(Schema schema, Object value) Convert the specified value to an Schema.Type.FLOAT64 double value.
static Float	convertToFloat(Schema schema, Object value) Convert the specified value to an Schema.Type.FLOAT32 float value.
static Integer	convertToInteger(Schema schema, Object value) Convert the specified value to an Schema.Type.INT32 int value.
static List<?>	convertToList(Schema schema, Object value) Convert the specified value to an Schema.Type.ARRAY value.
static Long	convertToLong(Schema schema, Object value) Convert the specified value to an Schema.Type.INT64 long value.
static Map<?,?>	convertToMap(Schema schema, Object value) Convert the specified value to an Schema.Type.MAP value.
static Short	convertToShort(Schema schema, Object value) Convert the specified value to an Schema.Type.INT16 short value.
static String	convertToString(Schema schema, Object value) Convert the specified value to an Schema.Type.STRING value.
static Struct	convertToStruct(Schema schema, Object value) Convert the specified value to an Schema.Type.STRUCT value.
static Date	convertToTime(Schema schema, Object value) Convert the specified value to an time value.
static Date	convertToTimestamp(Schema schema, Object value) Convert the specified value to an timestamp value.
static DateFormat	dateFormatFor(Date value)
protected static String	escape(String value)
static Schema	inferSchema(Object value) If possible infer a schema for the given value.
protected static SchemaAndValue	parse(Values.Parser parser, boolean embedded)
static SchemaAndValue	parseString(String value) Parse the specified string representation of a value into its schema and value.

Methods inherited from class java.lang.Object

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

Constructor Detail

Values

public Values()

Method Detail

convertToBoolean

public static Boolean convertToBoolean(Schema schema,
                                       Object value)
                                throws DataException

Convert the specified value to an Schema.Type.BOOLEAN value. The supplied schema is required if the value is a logical type when the schema contains critical information that might be necessary for converting to a boolean.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a boolean, or null if the supplied value was null

Throws:

DataException - if the value could not be converted to a boolean

convertToByte

public static Byte convertToByte(Schema schema,
                                 Object value)
                          throws DataException

Convert the specified value to an Schema.Type.INT8 byte value. The supplied schema is required if the value is a logical type when the schema contains critical information that might be necessary for converting to a byte.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a byte, or null if the supplied value was null

Throws:

DataException - if the value could not be converted to a byte

convertToShort

public static Short convertToShort(Schema schema,
                                   Object value)
                            throws DataException

Convert the specified value to an Schema.Type.INT16 short value. The supplied schema is required if the value is a logical type when the schema contains critical information that might be necessary for converting to a short.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a short, or null if the supplied value was null

Throws:

DataException - if the value could not be converted to a short

convertToInteger

public static Integer convertToInteger(Schema schema,
                                       Object value)
                                throws DataException

Convert the specified value to an Schema.Type.INT32 int value. The supplied schema is required if the value is a logical type when the schema contains critical information that might be necessary for converting to an integer.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as an integer, or null if the supplied value was null

Throws:

DataException - if the value could not be converted to an integer

convertToLong

public static Long convertToLong(Schema schema,
                                 Object value)
                          throws DataException

Convert the specified value to an Schema.Type.INT64 long value. The supplied schema is required if the value is a logical type when the schema contains critical information that might be necessary for converting to a long.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a long, or null if the supplied value was null

Throws:

DataException - if the value could not be converted to a long

convertToFloat

public static Float convertToFloat(Schema schema,
                                   Object value)
                            throws DataException

Convert the specified value to an Schema.Type.FLOAT32 float value. The supplied schema is required if the value is a logical type when the schema contains critical information that might be necessary for converting to a floating point number.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a float, or null if the supplied value was null

Throws:

DataException - if the value could not be converted to a float

convertToDouble

public static Double convertToDouble(Schema schema,
                                     Object value)
                              throws DataException

Convert the specified value to an Schema.Type.FLOAT64 double value. The supplied schema is required if the value is a logical type when the schema contains critical information that might be necessary for converting to a floating point number.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a double, or null if the supplied value was null

Throws:

DataException - if the value could not be converted to a double

convertToString

public static String convertToString(Schema schema,
                                     Object value)

Convert the specified value to an Schema.Type.STRING value. Not supplying a schema may limit the ability to convert to the desired type.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a string, or null if the supplied value was null

convertToList

public static List<?> convertToList(Schema schema,
                                    Object value)

Convert the specified value to an Schema.Type.ARRAY value. If the value is a string representation of an array, this method will parse the string and its elements to infer the schemas for those elements. Thus, this method supports arrays of other primitives and structured types. If the value is already an array (or list), this method simply casts and returns it.

This method currently does not use the schema, though it may be used in the future.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a list, or null if the supplied value was null

Throws:

DataException - if the value cannot be converted to a list value

convertToMap

public static Map<?,?> convertToMap(Schema schema,
                                    Object value)

Convert the specified value to an Schema.Type.MAP value. If the value is a string representation of a map, this method will parse the string and its entries to infer the schemas for those entries. Thus, this method supports maps with primitives and structured keys and values. If the value is already a map, this method simply casts and returns it.

This method currently does not use the schema, though it may be used in the future.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a map, or null if the supplied value was null

Throws:

DataException - if the value cannot be converted to a map value

convertToStruct

public static Struct convertToStruct(Schema schema,
                                     Object value)

Convert the specified value to an Schema.Type.STRUCT value. Structs cannot be converted from other types, so this method returns a struct only if the supplied value is a struct. If not a struct, this method throws an exception.

This method currently does not use the schema, though it may be used in the future.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a struct, or null if the supplied value was null

Throws:

DataException - if the value is not a struct

convertToTime

public static Date convertToTime(Schema schema,
                                 Object value)

Convert the specified value to an time value. Not supplying a schema may limit the ability to convert to the desired type.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a time, or null if the supplied value was null

Throws:

DataException - if the value cannot be converted to a time value

convertToDate

public static Date convertToDate(Schema schema,
                                 Object value)

Convert the specified value to an date value. Not supplying a schema may limit the ability to convert to the desired type.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a date, or null if the supplied value was null

Throws:

DataException - if the value cannot be converted to a date value

convertToTimestamp

public static Date convertToTimestamp(Schema schema,
                                      Object value)

Convert the specified value to an timestamp value. Not supplying a schema may limit the ability to convert to the desired type.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a timestamp, or null if the supplied value was null

Throws:

DataException - if the value cannot be converted to a timestamp value

convertToDecimal

public static BigDecimal convertToDecimal(Schema schema,
                                          Object value,
                                          int scale)

Convert the specified value to an decimal value. Not supplying a schema may limit the ability to convert to the desired type.

Parameters:

schema - the schema for the value; may be null

value - the value to be converted; may be null

Returns:

the representation as a decimal, or null if the supplied value was null

Throws:

DataException - if the value cannot be converted to a decimal value

inferSchema

public static Schema inferSchema(Object value)

If possible infer a schema for the given value.

Parameters:

value - the value whose schema is to be inferred; may be null

Returns:

the inferred schema, or null if the value is null or no schema could be inferred

parseString

public static SchemaAndValue parseString(String value)

Parse the specified string representation of a value into its schema and value.

Parameters:

value - the string form of the value

Returns:

the schema and value; never null, but whose schema and value may be null

See Also:

convertToString(org.apache.kafka.connect.data.Schema, java.lang.Object)

convertTo

protected static Object convertTo(Schema toSchema,
                                  Schema fromSchema,
                                  Object value)
                           throws DataException

Convert the value to the desired type.

Parameters:

toSchema - the schema for the desired type; may not be null

fromSchema - the schema for the supplied value; may be null if not known

Returns:

the converted value; never null

Throws:

DataException - if the value could not be converted to the desired type

asLong

protected static long asLong(Object value,
                             Schema fromSchema,
                             Throwable error)

Convert the specified value to the desired scalar value type.

Parameters:

value - the value to be converted; may not be null

fromSchema - the schema for the current value type; may not be null

error - any previous error that should be included in an exception message; may be null

Returns:

the long value after conversion; never null

Throws:

DataException - if the value could not be converted to a long

asDouble

protected static double asDouble(Object value,
                                 Schema schema,
                                 Throwable error)

Convert the specified value with the desired floating point type.

Parameters:

value - the value to be converted; may not be null

schema - the schema for the current value type; may not be null

error - any previous error that should be included in an exception message; may be null

Returns:

the double value after conversion; never null

Throws:

DataException - if the value could not be converted to a double

append

protected static void append(StringBuilder sb,
                             Object value,
                             boolean embedded)

appendIterable

protected static void appendIterable(StringBuilder sb,
                                     Iterator<?> iter)

escape

protected static String escape(String value)

dateFormatFor

public static DateFormat dateFormatFor(Date value)

parse

protected static SchemaAndValue parse(Values.Parser parser,
                                      boolean embedded)
                               throws NoSuchElementException

Throws:

NoSuchElementException

commonSchemaFor

protected static Schema commonSchemaFor(Schema previous,
                                        SchemaAndValue latest)

alignListEntriesWithSchema

protected static List<Object> alignListEntriesWithSchema(Schema schema,
                                                         List<Object> input)

alignMapKeysAndValuesWithSchema

protected static Map<Object,Object> alignMapKeysAndValuesWithSchema(Schema mapSchema,
                                                                    Map<Object,Object> input)