com.datastax.driver.extras.codecs.arrays

Class AbstractArrayCodec<T>

java.lang.Object

com.datastax.driver.core.TypeCodec<T>

com.datastax.driver.extras.codecs.arrays.AbstractArrayCodec<T>

Type Parameters:

T - The Java array type this codec handles

Direct Known Subclasses:

AbstractPrimitiveArrayCodec, ObjectArrayCodec

public abstract class AbstractArrayCodec<T>
extends TypeCodec<T>

Base class for all codecs dealing with Java arrays. This class aims to reduce the amount of code required to create such codecs.

Nested Class Summary

Nested classes/interfaces inherited from class com.datastax.driver.core.TypeCodec

TypeCodec.AbstractCollectionCodec<E,C extends Collection<E>>, TypeCodec.AbstractMapCodec<K,V>, TypeCodec.AbstractTupleCodec<T>, TypeCodec.AbstractUDTCodec<T>, TypeCodec.PrimitiveBooleanCodec, TypeCodec.PrimitiveByteCodec, TypeCodec.PrimitiveDoubleCodec, TypeCodec.PrimitiveFloatCodec, TypeCodec.PrimitiveIntCodec, TypeCodec.PrimitiveLongCodec, TypeCodec.PrimitiveShortCodec

Field Summary

Fields inherited from class com.datastax.driver.core.TypeCodec

cqlType, javaType

Constructor Summary

Constructors

Constructor and Description
AbstractArrayCodec(DataType.CollectionType cqlType, Class<T> javaClass)

Method Summary

Modifier and Type	Method and Description
String	format(T array) Format the given value as a valid CQL literal according to the CQL type handled by this codec.
protected abstract void	formatElement(StringBuilder output, T array, int index) Format the indexth element of array to output.
protected abstract T	newInstance(int size) Create a new array instance with the given size.
T	parse(String value) Parse the given CQL literal into an instance of the Java type handled by this codec.
protected abstract void	parseElement(String input, T array, int index) Parse the indexth element of array from input.

Methods inherited from class com.datastax.driver.core.TypeCodec

accepts, accepts, accepts, accepts, ascii, bigint, blob, cboolean, cdouble, cfloat, cint, counter, custom, date, decimal, deserialize, duration, getCqlType, getJavaType, inet, list, map, serialize, set, smallInt, time, timestamp, timeUUID, tinyInt, toString, tuple, userType, uuid, varchar, varint

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractArrayCodec

public AbstractArrayCodec(DataType.CollectionType cqlType,
                          Class<T> javaClass)

Parameters:

cqlType - The CQL type. Must be a list type.

javaClass - The Java type. Must be an array class.

Method Detail

format

public String format(T array)
              throws InvalidTypeException

Description copied from class: TypeCodec

Format the given value as a valid CQL literal according to the CQL type handled by this codec.

Implementors should take care of quoting and escaping the resulting CQL literal where applicable. Null values should be accepted; in most cases, implementations should return the CQL keyword "NULL" for null inputs.

Implementing this method is not strictly mandatory. It is used:

1. in the query builder, when values are inlined in the query string (see BuiltStatement for a detailed explanation of when this happens);
2. in the QueryLogger, if parameter logging is enabled;
3. to format the INITCOND in AggregateMetadata.asCQLQuery(boolean);
4. in the toString() implementation of some objects (UDTValue, TupleValue, and the internal representation of a ROWS response), which may appear in driver logs.

If you choose not to implement this method, you should not throw an exception but instead return a constant string (for example "XxxCodec.format not implemented").

Specified by:

format in class TypeCodec<T>

Parameters:

array - An instance of T; may be null.

Returns:

CQL string

Throws:

InvalidTypeException - if the given value does not have the expected type

parse

public T parse(String value)
        throws InvalidTypeException

Description copied from class: TypeCodec

Parse the given CQL literal into an instance of the Java type handled by this codec.

Implementors should take care of unquoting and unescaping the given CQL string where applicable. Null values and empty Strings should be accepted, as well as the string "NULL"; in most cases, implementations should interpret these inputs has equivalent to a null reference.

Implementing this method is not strictly mandatory: internally, the driver only uses it to parse the INITCOND when building the metadata of an aggregate function (and in most cases it will use a built-in codec, unless the INITCOND has a custom type).

Specified by:

parse in class TypeCodec<T>

Parameters:

value - The CQL string to parse, may be null or empty.

Returns:

An instance of T; may be null on a null input.

Throws:

InvalidTypeException - if the given value cannot be parsed into the expected type

newInstance

protected abstract T newInstance(int size)

Create a new array instance with the given size.

Parameters:

size - The size of the array to instantiate.

Returns:

a new array instance with the given size.

formatElement

protected abstract void formatElement(StringBuilder output,
                                      T array,
                                      int index)

Format the indexth element of array to output.

Parameters:

output - The StringBuilder to write to.

array - The array to read from.

index - The element index.

parseElement

protected abstract void parseElement(String input,
                                     T array,
                                     int index)

Parse the indexth element of array from input.

Parameters:

input - The String to read from.

array - The array to write to.

index - The element index.