proper.database
Class Sparser

java.lang.Object
  proper.core.ProperObject
      proper.database.ConnectorObject
          proper.database.ExecutorObject
              proper.database.Sparser

All Implemented Interfaces:

ProperInterface

public class Sparser
extends ExecutorObject

This class retrieves a certain percentage of data from a table. Sometimes it is necessary to retrieve only a small sample of a huge table. If a a uniformly distributed sample is preferred the classfield has to be set, too. The Reader class uses this.
Via the iterator you can access the IDs that were chosen for retrieval.

Version:

$Revision: 1.2 $

Author:

FracPete

See Also:

Reader.setPercentage(double)

Field Summary

Fields inherited from interface proper.core.ProperInterface

VERSION

Constructor Summary

Sparser(Connector conn)
initializes the object

Method Summary

void	clear() resets the sparser (percentage back to 0%, i.e.
java.lang.String	getClassField() returns the currently set column used as class
int	getClassFieldType() returns the sql type of the classfield
java.lang.String	getIndex() returns the index the keys are taken from
int	getIndexType() returns the sql type of the index
double	getKeyRatio() returns the ratio between all rows and all distinct rows, important for tables that do not contain a unique key (then the ratio is >1.0)
boolean	getOnlyClassified() returns whether we only want classified instances
boolean	getOnlyUnclassified() returns whether we only want unclassified instances
double	getPercentage() returns the currently set percentage
java.lang.String	getTable() returns the currently set table
java.util.Iterator	iterator() returns an iterator over the stored keys
void	setClassField(java.lang.String classField) sets the column to use as class
void	setIndex(java.lang.String index) sets the index to get the keys from (can be determined automatically!)
void	setOnlyClassified(boolean onlyClassified) sets whether we only want to retrieve keys for classified instances, i.e.
void	setOnlyUnclassified(boolean onlyUnclassified) sets whether we only want to retrieve keys for unclassified instances, i.e.
void	setPercentage(double percentage) sets the percentage of rows to retrieve (0-100), where 0 and 100 mean both "all rows"
void	setTable(java.lang.String table) sets the table to work on
int	size() returns the number of stored keys
java.lang.String	toString() returns some information about the current state

Methods inherited from class proper.database.ExecutorObject

getExecutor, getLastException, getLastStatement

Methods inherited from class proper.database.ConnectorObject

getConnector

Methods inherited from class proper.core.ProperObject

addListener, addOutput, classInVerbose, debugprint, debugprint, debugprint, debugprint, debugprintln, debugprintln, debugprintln, debugprintln, debugprintln, getListeners, getRuntime, getVerbose, getVerboseLevel, getVerboseLevelForClass, getVerboseString, getVerboseStringForClass, notifyListener, notifyListeners, print, print, print, print, println, println, println, println, println, printMemory, removeListener, setOutput, setVerbose, setVerboseLevel, setVerboseString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Sparser

public Sparser(Connector conn)

initializes the object

Method Detail

clear

public void clear()

resets the sparser (percentage back to 0%, i.e. all)

setTable

public void setTable(java.lang.String table)

sets the table to work on

getTable

public java.lang.String getTable()

returns the currently set table

setIndex

public void setIndex(java.lang.String index)

sets the index to get the keys from (can be determined automatically!)

getIndex

public java.lang.String getIndex()

returns the index the keys are taken from

getIndexType

public int getIndexType()

returns the sql type of the index

See Also:

Types

setClassField

public void setClassField(java.lang.String classField)

sets the column to use as class

getClassField

public java.lang.String getClassField()

returns the currently set column used as class

getClassFieldType

public int getClassFieldType()

returns the sql type of the classfield

See Also:

Types

setOnlyClassified

public void setOnlyClassified(boolean onlyClassified)

sets whether we only want to retrieve keys for classified instances, i.e. the classfield has to be set to determine the classified state

getOnlyClassified

public boolean getOnlyClassified()

returns whether we only want classified instances

setOnlyUnclassified

public void setOnlyUnclassified(boolean onlyUnclassified)

sets whether we only want to retrieve keys for unclassified instances, i.e. the classfield has to be set to determine the unclassified state

getOnlyUnclassified

public boolean getOnlyUnclassified()

returns whether we only want unclassified instances

setPercentage

public void setPercentage(double percentage)

sets the percentage of rows to retrieve (0-100), where 0 and 100 mean both "all rows"

getPercentage

public double getPercentage()

returns the currently set percentage

getKeyRatio

public double getKeyRatio()

returns the ratio between all rows and all distinct rows, important for tables that do not contain a unique key (then the ratio is >1.0)

iterator

public java.util.Iterator iterator()

returns an iterator over the stored keys

size

public int size()

returns the number of stored keys

toString

public java.lang.String toString()

returns some information about the current state

Overrides:

toString in class ProperObject