org.apache.cassandra.service.pager

Class RangeNamesQueryPager

java.lang.Object

org.apache.cassandra.service.pager.RangeNamesQueryPager

All Implemented Interfaces:

QueryPager

public class RangeNamesQueryPager
extends java.lang.Object

Pages a RangeSliceCommand whose predicate is a name query. Note: this only work for NamesQueryFilter that have countCQL3Rows() set, because this assumes the pageSize is counted in number of internal rows returned. More precisely, this doesn't do in-row paging so this assumes that the counter returned by columnCounter() will count 1 for each internal row.

Field Summary

Fields

Modifier and Type	Field and Description
protected CFMetaData	cfm
protected IDiskAtomFilter	columnFilter

Method Summary

Methods

Modifier and Type	Method and Description
ColumnCounter	columnCounter()
protected boolean	containsPreviousLast(Row first)
java.util.List<Row>	fetchPage(int pageSize) Fetches the next page.
protected static java.nio.ByteBuffer	firstName(ColumnFamily cf)
boolean	isExhausted() Whether or not this pager is exhausted, i.e.
protected static java.nio.ByteBuffer	lastName(ColumnFamily cf)
int	maxRemaining() The maximum number of cells/CQL3 row that we may still have to return.
protected java.util.List<Row>	queryNextPage(int pageSize, ConsistencyLevel consistencyLevel, boolean localQuery)
protected boolean	recordLast(Row last)
protected void	restoreState(int remaining, boolean lastWasRecorded)
PagingState	state() Get the current state of the pager.
long	timestamp()

Methods inherited from class java.lang.Object

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

Field Detail

cfm

protected final CFMetaData cfm

columnFilter

protected final IDiskAtomFilter columnFilter

Method Detail

state

public PagingState state()

Description copied from interface: QueryPager

Get the current state of the pager. The state can allow to restart the paging on another host from where we are at this point.

Returns:

the current paging state. Will return null if paging is at the beginning. If the pager is exhausted, the result is undefined.

queryNextPage

protected java.util.List<Row> queryNextPage(int pageSize,
                                ConsistencyLevel consistencyLevel,
                                boolean localQuery)
                                     throws RequestExecutionException

Throws:

RequestExecutionException

containsPreviousLast

protected boolean containsPreviousLast(Row first)

recordLast

protected boolean recordLast(Row last)

fetchPage

public java.util.List<Row> fetchPage(int pageSize)
                              throws RequestValidationException,
                                     RequestExecutionException

Description copied from interface: QueryPager

Fetches the next page.

Specified by:

fetchPage in interface QueryPager

Parameters:

pageSize - the maximum number of elements to return in the next page.

Returns:

the page of result.

Throws:

RequestValidationException

RequestExecutionException

restoreState

protected void restoreState(int remaining,
                boolean lastWasRecorded)

isExhausted

public boolean isExhausted()

Description copied from interface: QueryPager

Whether or not this pager is exhausted, i.e. whether or not a call to fetchPage may return more result.

Specified by:

isExhausted in interface QueryPager

Returns:

whether the pager is exhausted.

maxRemaining

public int maxRemaining()

Description copied from interface: QueryPager

The maximum number of cells/CQL3 row that we may still have to return. In other words, that's the initial user limit minus what we've already returned (note that it's not how many we *will* return, just the upper limit on it).

Specified by:

maxRemaining in interface QueryPager

timestamp

public long timestamp()

columnCounter

public ColumnCounter columnCounter()

firstName

protected static java.nio.ByteBuffer firstName(ColumnFamily cf)

lastName

protected static java.nio.ByteBuffer lastName(ColumnFamily cf)