Package org.apache.cassandra.db.filter

Class RowFilter.UserExpression

java.lang.Object

org.apache.cassandra.db.filter.RowFilter.Expression

org.apache.cassandra.db.filter.RowFilter.UserExpression

Enclosing class:

RowFilter

public abstract static class RowFilter.UserExpression
extends RowFilter.Expression

A user defined filtering expression. These may be added to RowFilter programmatically by a QueryHandler implementation. No concrete implementations are provided and adding custom impls to the classpath is a task for operators (needless to say, this is something of a power user feature). Care must also be taken to register implementations, via the static register method during system startup. An implementation and its corresponding Deserializer must be registered before sending or receiving any messages containing expressions of that type. Use of custom filtering expressions in a mixed version cluster should be handled with caution as the order in which types are registered is significant: if continuity of use during upgrades is important, new types should registered last and obsoleted types should still be registered ( or dummy implementations registered in their place) to preserve consistent identifiers across the cluster). During serialization, the identifier for the Deserializer implementation is prepended to the implementation specific payload. To deserialize, the identifier is read first to obtain the Deserializer, which then provides the concrete expression instance.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	RowFilter.UserExpression.Deserializer

Nested classes/interfaces inherited from class org.apache.cassandra.db.filter.RowFilter.Expression

RowFilter.Expression.Kind

Field Summary

Fields inherited from class org.apache.cassandra.db.filter.RowFilter.Expression

column, operator, value

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	UserExpression(ColumnMetadata column, Operator operator, ByteBuffer value)

Method Summary

Modifier and Type	Method	Description
protected RowFilter.Expression.Kind	kind()
static void	register(Class<? extends RowFilter.UserExpression> expressionClass, RowFilter.UserExpression.Deserializer deserializer)
protected abstract void	serialize(DataOutputPlus out, int version)
protected abstract long	serializedSize(int version)

Methods inherited from class org.apache.cassandra.db.filter.RowFilter.Expression

column, equals, getIndexValue, getValue, hashCode, isContains, isContainsKey, isCustom, isSatisfiedBy, isUserDefined, operator, toCQLString, toString, toString, validate, validateForIndexing

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

UserExpression

protected UserExpression(ColumnMetadata column,
 Operator operator,
 ByteBuffer value)

Method Details

register

public static void register(Class<? extends RowFilter.UserExpression> expressionClass,
 RowFilter.UserExpression.Deserializer deserializer)

kind

protected RowFilter.Expression.Kind kind()

Specified by:

kind in class RowFilter.Expression

serialize

protected abstract void serialize(DataOutputPlus out,
 int version)
                           throws IOException

Throws:

IOException

serializedSize

protected abstract long serializedSize(int version)