com.bigdata.bop.join

Class JVMDistinctFilter

java.lang.Object

com.bigdata.bop.join.JVMDistinctFilter

All Implemented Interfaces:

IDistinctFilter

public class JVMDistinctFilter
extends Object
implements IDistinctFilter

Utility class for imposing a DISTINCT filter on IBindingSet. This class is thread-safe. It is based on a ConcurrentHashMap.

Author:

Bryan Thompson

Constructor Summary

Constructors

Constructor and Description
JVMDistinctFilter(IVariable<?>[] vars, int initialCapacity, float loadFactor, int concurrencyLevel)

Method Summary

Methods

Modifier and Type	Method and Description
IBindingSet	accept(IBindingSet bset) If the bindings are distinct for the configured variables then return a new IBindingSet consisting of only the selected variables.
long	filterSolutions(ICloseableIterator<IBindingSet[]> itr, BOpStats stats, IBuffer<IBindingSet> sink) Vectored DISTINCT.
IVariable<?>[]	getProjectedVars() The variables that are being projected out of the DISTINCT filter.
void	release() Discard the map backing this filter.

Methods inherited from class java.lang.Object

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

Constructor Detail

JVMDistinctFilter

public JVMDistinctFilter(IVariable<?>[] vars,
                 int initialCapacity,
                 float loadFactor,
                 int concurrencyLevel)

Parameters:

vars - The set of variables on which the DISTINCT filter will be imposed. Only these variables will be present in the "accepted" solutions. Any variable bindings not specified in this array will be dropped.

initialCapacity -

loadFactor -

concurrencyLevel -

Method Detail

release

public void release()

Description copied from interface: IDistinctFilter

Discard the map backing this filter.

Specified by:

release in interface IDistinctFilter

getProjectedVars

public IVariable<?>[] getProjectedVars()

Description copied from interface: IDistinctFilter

The variables that are being projected out of the DISTINCT filter. The solutions will be DISTINCT on this combination of variables. Bindings on other variables will be dropped.

Specified by:

getProjectedVars in interface IDistinctFilter

accept

public IBindingSet accept(IBindingSet bset)

Description copied from interface: IDistinctFilter

If the bindings are distinct for the configured variables then return a new IBindingSet consisting of only the selected variables.

Specified by:

accept in interface IDistinctFilter

Parameters:

bset - The binding set to be filtered.

Returns:

A new IBindingSet containing only the distinct as bound values -or- null if the binding set duplicates a solution which was already accepted.

filterSolutions

public long filterSolutions(ICloseableIterator<IBindingSet[]> itr,
                   BOpStats stats,
                   IBuffer<IBindingSet> sink)

Description copied from interface: IDistinctFilter

Vectored DISTINCT.

Specified by:

filterSolutions in interface IDistinctFilter

Parameters:

itr - The source solutions.

stats - Statistics object to be updated.

sink - The sink onto which the DISTINCT solutions will be written.

Returns:

The #of DISTINCT solutions.