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org.apache.derby.catalog.types
Class StatisticsImpl  

java.lang.Object
  org.apache.derby.catalog.types.StatisticsImpl

All Implemented Interfaces:

java.io.Externalizable, org.apache.derby.iapi.services.io.Formatable, java.io.Serializable, org.apache.derby.catalog.Statistics, org.apache.derby.iapi.services.io.TypedFormat

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public class StatisticsImpl

extends java.lang.Object

implements org.apache.derby.catalog.Statistics, org.apache.derby.iapi.services.io.Formatable

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Field Summary
private  long	numRows
private  long	numUnique

 

Constructor Summary

StatisticsImpl()           Zero argument constructor for Formatable Interface

StatisticsImpl(long numRows, long numUnique)           Constructor for StatisticsImpl.

 

Method Summary
int	getTypeFormatId()           Get a universally unique identifier for the type of this object.
void	readExternal(java.io.ObjectInput in)           This method restores an object's state by reading in the instance data for the object from the passed in stream.
double	selectivity(java.lang.Object[] predicates)
java.lang.String	toString()           Convert this Object to a human-readable String.
void	writeExternal(java.io.ObjectOutput out)           Write this object to a stream of stored objects.

 

Methods inherited from class java.lang.Object

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

 

Field Detail

numRows

private long numRows

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numUnique

private long numUnique

Constructor Detail

StatisticsImpl

public StatisticsImpl(long numRows,
                      long numUnique)

Constructor for StatisticsImpl.

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StatisticsImpl

public StatisticsImpl()

Zero argument constructor for Formatable Interface

Method Detail

selectivity

public double selectivity(java.lang.Object[] predicates)

Specified by:

selectivity in interface org.apache.derby.catalog.Statistics

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readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException

Description copied from interface: java.io.Externalizable

This method restores an object's state by reading in the instance data for the object from the passed in stream. Note that this stream is not a subclass of InputStream, but rather is a class that implements the ObjectInput interface. That interface provides a mechanism for reading in Java data types from a stream.

Note that this method must be compatible with writeExternal. It must read back the exact same types that were written by that method in the exact order they were written.

If this method needs to read back an object instance, then the class for that object must be found and loaded. If that operation fails, then this method throws a ClassNotFoundException

Specified by:

readExternal in interface java.io.Externalizable

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writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException

Write this object to a stream of stored objects.

Specified by:

writeExternal in interface java.io.Externalizable

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getTypeFormatId

public int getTypeFormatId()

Description copied from interface: org.apache.derby.iapi.services.io.TypedFormat

Get a universally unique identifier for the type of this object.

Specified by:

getTypeFormatId in interface org.apache.derby.iapi.services.io.TypedFormat

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toString

public java.lang.String toString()

Description copied from class: java.lang.Object

Convert this Object to a human-readable String. There are no limits placed on how long this String should be or what it should contain. We suggest you make it as intuitive as possible to be able to place it into System.out.println() 55 and such.

It is typical, but not required, to ensure that this method never completes abruptly with a java.lang.RuntimeException.

This method will be called when performing string concatenation with this object. If the result is null, string concatenation will instead use "null".

The default implementation returns getClass().getName() + "@" + Integer.toHexString(hashCode()).

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> derby >> catalog >> [ types overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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