org.apache.cassandra.db

Class SinglePartitionReadQuery.Group<T extends SinglePartitionReadQuery>

java.lang.Object

org.apache.cassandra.db.SinglePartitionReadQuery.Group<T>

All Implemented Interfaces:

ReadQuery

Direct Known Subclasses:

SinglePartitionReadCommand.Group, VirtualTableSinglePartitionReadQuery.Group

Enclosing interface:

SinglePartitionReadQuery

public abstract static class SinglePartitionReadQuery.Group<T extends SinglePartitionReadQuery>
extends java.lang.Object
implements ReadQuery

Groups multiple single partition read queries.

Field Summary

Fields

Modifier and Type	Field and Description
java.util.List<T>	queries

Constructor Summary

Constructors

Constructor and Description
Group(java.util.List<T> queries, DataLimits limits)

Method Summary

Modifier and Type	Method and Description
ColumnFilter	columnFilter() A filter on which (non-PK) columns must be returned by the query.
PartitionIterator	executeInternal(ReadExecutionController controller) Execute the query for internal queries (that is, it basically executes the query locally).
UnfilteredPartitionIterator	executeLocally(ReadExecutionController executionController) Execute the query locally.
ReadExecutionController	executionController() Starts a new read operation.
QueryPager	getPager(PagingState pagingState, ProtocolVersion protocolVersion) Returns a pager for the query.
DataLimits	limits() The limits for the query.
TableMetadata	metadata() The metadata for the table this is a query on.
int	nowInSec() The time in seconds to use as "now" for this query.
RowFilter	rowFilter() Filters/Resrictions on CQL rows.
boolean	selectsClustering(DecoratedKey key, Clustering<?> clustering)
boolean	selectsFullPartition() Checks if this ReadQuery selects full partitions, that is it has no filtering on clustering or regular columns.
boolean	selectsKey(DecoratedKey key)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.cassandra.db.ReadQuery

empty, execute, isEmpty, maybeValidateIndex

Field Detail

queries

public final java.util.List<T extends SinglePartitionReadQuery> queries

Constructor Detail

Group

public Group(java.util.List<T> queries,
             DataLimits limits)

Method Detail

nowInSec

public int nowInSec()

Description copied from interface: ReadQuery

The time in seconds to use as "now" for this query.

We use the same time as "now" for the whole query to avoid considering different values as expired during the query, which would be buggy (would throw of counting amongst other things).

Specified by:

nowInSec in interface ReadQuery

Returns:

the time (in seconds) to use as "now".

limits

public DataLimits limits()

Description copied from interface: ReadQuery

The limits for the query.

Specified by:

limits in interface ReadQuery

Returns:

The limits for the query.

metadata

public TableMetadata metadata()

Description copied from interface: ReadQuery

The metadata for the table this is a query on.

Specified by:

metadata in interface ReadQuery

Returns:

the metadata for the table this is a query on.

selectsFullPartition

public boolean selectsFullPartition()

Description copied from interface: ReadQuery

Checks if this ReadQuery selects full partitions, that is it has no filtering on clustering or regular columns.

Specified by:

selectsFullPartition in interface ReadQuery

Returns:

true if this ReadQuery selects full partitions, false otherwise.

executionController

public ReadExecutionController executionController()

Description copied from interface: ReadQuery

Starts a new read operation.

This must be called before executeInternal and passed to it to protect the read. The returned object must be closed on all path and it is thus strongly advised to use it in a try-with-ressource construction.

Specified by:

executionController in interface ReadQuery

Returns:

a newly started execution controller for this ReadQuery.

executeInternal

public PartitionIterator executeInternal(ReadExecutionController controller)

Description copied from interface: ReadQuery

Execute the query for internal queries (that is, it basically executes the query locally).

Specified by:

executeInternal in interface ReadQuery

Parameters:

controller - the ReadExecutionController protecting the read.

Returns:

the result of the query.

executeLocally

public UnfilteredPartitionIterator executeLocally(ReadExecutionController executionController)

Description copied from interface: ReadQuery

Execute the query locally. This is similar to ReadQuery.executeInternal(ReadExecutionController) but it returns an unfiltered partition iterator that can be merged later on.

Specified by:

executeLocally in interface ReadQuery

Parameters:

executionController - the ReadExecutionController protecting the read.

Returns:

the result of the read query.

getPager

public QueryPager getPager(PagingState pagingState,
                           ProtocolVersion protocolVersion)

Description copied from interface: ReadQuery

Returns a pager for the query.

Specified by:

getPager in interface ReadQuery

Parameters:

pagingState - the PagingState to start from if this is a paging continuation. This can be null if this is the start of paging.

protocolVersion - the protocol version to use for the paging state of that pager.

Returns:

a pager for the query.

selectsKey

public boolean selectsKey(DecoratedKey key)

Specified by:

selectsKey in interface ReadQuery

Returns:

true if the read query would select the given key, including checks against the row filter, if checkRowFilter is true

selectsClustering

public boolean selectsClustering(DecoratedKey key,
                                 Clustering<?> clustering)

Specified by:

selectsClustering in interface ReadQuery

Returns:

true if the read query would select the given clustering, including checks against the row filter, if checkRowFilter is true

rowFilter

public RowFilter rowFilter()

Description copied from interface: ReadQuery

Filters/Resrictions on CQL rows.

This contains the restrictions that are not directly handled by the ClusteringIndexFilter. More specifically, this includes any non-PK column restrictions and can include some PK columns restrictions when those can't be satisfied entirely by the clustering index filter (because not all clustering columns have been restricted for instance). If there is 2ndary indexes on the table, one of this restriction might be handled by a 2ndary index.

Specified by:

rowFilter in interface ReadQuery

Returns:

the filter holding the expression that rows must satisfy.

columnFilter

public ColumnFilter columnFilter()

Description copied from interface: ReadQuery

A filter on which (non-PK) columns must be returned by the query.

Specified by:

columnFilter in interface ReadQuery

Returns:

which columns must be fetched by this query.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object