com.bigdata.btree.proc

Class RangeCountProcedure

java.lang.Object

com.bigdata.btree.proc.AbstractIndexProcedure<T>

com.bigdata.btree.proc.AbstractKeyRangeIndexProcedure<Long>

com.bigdata.btree.proc.RangeCountProcedure

All Implemented Interfaces:

IIndexProcedure<Long>, IKeyRangeIndexProcedure<Long>, IParallelizableIndexProcedure<Long>, IReadOnly, Externalizable, Serializable

public class RangeCountProcedure
extends AbstractKeyRangeIndexProcedure<Long>
implements IParallelizableIndexProcedure<Long>

This procedure computes a range count on an index.

See Also:

Serialized Form

Field Summary

Fields inherited from class com.bigdata.btree.proc.AbstractKeyRangeIndexProcedure

fromKey, toKey

Constructor Summary

Constructors

Constructor and Description
RangeCountProcedure() De-serialization ctor.
RangeCountProcedure(boolean exact, boolean deleted, byte[] fromKey, byte[] toKey) Range count using the specified bounds.

Method Summary

Methods

Modifier and Type	Method and Description
Long	apply(IIndex ndx) Range count of entries in a key range for the index.
boolean	isDeleted() Return true iff deleted tuples must be included in the result.
boolean	isExact() Return true iff the result count must be exact.
boolean	isReadOnly() Return true iff the procedure asserts that it will not write on the index.
void	readExternal(ObjectInput in)
void	writeExternal(ObjectOutput out)

Methods inherited from class com.bigdata.btree.proc.AbstractKeyRangeIndexProcedure

constrainFromKey, constrainToKey, getFromKey, getToKey, readKeys, writeKeys

Methods inherited from class java.lang.Object

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

Constructor Detail

RangeCountProcedure

public RangeCountProcedure()

De-serialization ctor.

RangeCountProcedure

public RangeCountProcedure(boolean exact,
                   boolean deleted,
                   byte[] fromKey,
                   byte[] toKey)

Range count using the specified bounds.

Parameters:

exact - iff an exact range count is required.

deleted - iff deleted tuples must be included in the count.

fromKey - The lower bound (inclusive) -or- null if there is no lower bound.

toKey - The upper bound (exclusive) -or- null if there is no upper bound.

Throws:

IllegalArgumentException - if exact is false and deleted is true (there is no approximate reporting for range counts of deleted and undeleted tuples).

Method Detail

isReadOnly

public final boolean isReadOnly()

Description copied from interface: IReadOnly

Return true iff the procedure asserts that it will not write on the index. When true, the procedure may be run against a view of the index that is read-only or which allows concurrent processes to read on the same index object. When false the procedure will be run against a mutable view of the index (assuming that the procedure is executed in a context that has access to a mutable index view).

Specified by:

isReadOnly in interface IReadOnly

isExact

public final boolean isExact()

Return true iff the result count must be exact.

isDeleted

public final boolean isDeleted()

Return true iff deleted tuples must be included in the result.

apply

public Long apply(IIndex ndx)

Range count of entries in a key range for the index.

Note: When the index IndexMetadata.getDeleteMarkers() this method reports the upper bound estimate of the #of key-value pairs in the key range of the index. The estimate is an upper bound because duplicate or deleted entries in that have not been eradicated through a suitable compacting merge will be reported. An exact count may be obtained using a range iterator by NOT requesting either the keys or the values.

Specified by:

apply in interface IIndexProcedure<Long>

Parameters:

ndx - The index.

Returns:

The upper bound estimate of the #of key-value pairs in the key range of the named index.

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Overrides:

readExternal in class AbstractKeyRangeIndexProcedure<Long>

Throws:

IOException

ClassNotFoundException

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Overrides:

writeExternal in class AbstractKeyRangeIndexProcedure<Long>

Throws:

IOException