edu.udo.cs.yale.example
Interface ExampleTable

All Known Implementing Classes:

AbstractExampleTable, DatabaseExampleTable, MemoryExampleTable, RandomExampleTable

public interface ExampleTable

This class is the core data supplier for example sets. Several example sets can use the same data and access the attribute values by reference. Thats means that ExampleTable contains all data like in a database management systems and all ExampleSets are only views on the data. The ExampleSets themself do hence not contain any data rows and can be cloned without copying the data.

Changing the data in the ExampleTable will change the data for all views (ExampleSets). On the other hand, the changes for one view (ExampleSet) like adding or removing Attributes will not change the ExampleTable and will also not change other views (ExampleSets).

Version:

$Id: ExampleTable.java,v 2.42 2006/08/03 14:39:28 ingomierswa Exp $

Author:

Ingo Mierswa

Method Summary

int	addAttribute(Attribute a) Adds the attribute to the list of attributes assigning it a free column index.
void	addAttributes(java.util.Collection<Attribute> newAttributes) Adds all Attributes in newAttributes to the end of the list of attributes, creating new data columns if necessary.
ExampleSet	createCompleteExampleSet(Attribute label, Attribute predictedLabel, Attribute weight, Attribute idAttribute) Returns a new example set with all attributes switched on.
ExampleSet	createCompleteExampleSet(java.util.Map<java.lang.String,Attribute> specialAttributes) Returns a new example set with all attributes switched on.
ExampleSet	createExampleSet(AttributeSet attributeSet) Returns a new example set with all attributes of the given attribute set.
Attribute	findAttribute(java.lang.String name) Returns the attribute with the given name.
Attribute	getAttribute(Attribute attribute) Returns an Attribute which is constructed in the same way as attribute.
Attribute	getAttribute(int i) Returns the attribute of the column number i.
int	getAttributeCount() Returns the number of non null attributes.
Attribute[]	getAttributes() Returns a new array containing all Attributes.
int	getBlockEndIndex(int startindex) Returns the last attribute index belonging to the block starting at startindex.
DataRowReader	getDataReader() Returns an Iterator for example data given as DataRow objects.
DataRow	getDataRow(int index) Returns the i-th data row.
int	getHighestBlockNr() Gets the currently highest used block number.
int	getNextFreeBlockNr() Returns a new unused blockNr.
int	getNumberOfAttributes() Returns the number of attributes.
int	getSize() Returns the number of examples.
void	removeAttribute(Attribute attribute) Equivalent to calling removeAttribute(attribute.getTableIndex()).
void	removeAttribute(int index) Sets the attribute with the given index to null.
java.lang.String	toDataString()
java.lang.String	toString()

Method Detail

getSize

int getSize()

Returns the number of examples.

getDataReader

DataRowReader getDataReader()

Returns an Iterator for example data given as DataRow objects. This should be used in all cases where iteration is desired. Since getDataRow(int) does not ensure to work in an efficient way the usage of this method is preferred (instead using for-loops).

getDataRow

DataRow getDataRow(int index)

Returns the i-th data row. Calling methods cannot rely on the efficiency of this method. Memory based example tables should return the data row in O(1).

getAttributes

Attribute[] getAttributes()

Returns a new array containing all Attributes.

getAttribute

Attribute getAttribute(int i)

Returns the attribute of the column number i. Attention: This value may return null if the column was marked unused.

findAttribute

Attribute findAttribute(java.lang.String name)
                        throws OperatorException

Returns the attribute with the given name.

Throws:

OperatorException

addAttributes

void addAttributes(java.util.Collection<Attribute> newAttributes)

Adds all Attributes in newAttributes to the end of the list of attributes, creating new data columns if necessary.

addAttribute

int addAttribute(Attribute a)

Adds the attribute to the list of attributes assigning it a free column index.

removeAttribute

void removeAttribute(Attribute attribute)

Equivalent to calling removeAttribute(attribute.getTableIndex()).

removeAttribute

void removeAttribute(int index)

Sets the attribute with the given index to null. Afterwards, this column can be reused. Callers must make sure, that no other example set contains a reference to this column. Otherwise its data will be messed up. Ususally this is only possible if an operator generates intermediate attributes, like a validation chain or a feature generator. If the attribute already was removed, this method returns silently.

getNumberOfAttributes

int getNumberOfAttributes()

Returns the number of attributes. Attention: Callers that use a for-loop and retrieving Attributes by calling AbstractExampleTable.getAttribute(int) must keep in mind, that some of these attributes may be null.

getAttributeCount

int getAttributeCount()

Returns the number of non null attributes. Attention: Since there are null attributes in the list, the return value of this method must not be used in a for-loop!

See Also:

getNumberOfAttributes().

getHighestBlockNr

int getHighestBlockNr()

Gets the currently highest used block number.

getNextFreeBlockNr

int getNextFreeBlockNr()

Returns a new unused blockNr. BUG: Achtung, wenn Attributdatei Blocknummer enthaelt. Wird hier nicht beruecksichtigt.

getBlockEndIndex

int getBlockEndIndex(int startindex)

Returns the last attribute index belonging to the block starting at startindex.

getAttribute

Attribute getAttribute(Attribute attribute)

Returns an Attribute which is constructed in the same way as attribute. Attention:

• This method do not use the equals method of attribute which only checks the name and table index (which is actually the meaning of equals) but it compares the construction descriptions of both attributes. This is especially useful for automatic feature construction algorithms which should not regenerate the same attribute.
• May return null (deleted columns).

createExampleSet

ExampleSet createExampleSet(AttributeSet attributeSet)

Returns a new example set with all attributes of the given attribute set.

createCompleteExampleSet

ExampleSet createCompleteExampleSet(Attribute label,
                                    Attribute predictedLabel,
                                    Attribute weight,
                                    Attribute idAttribute)

Returns a new example set with all attributes switched on.

createCompleteExampleSet

ExampleSet createCompleteExampleSet(java.util.Map<java.lang.String,Attribute> specialAttributes)

Returns a new example set with all attributes switched on. The attributes in the given map will be used as special attributes, all other attributes given at creation time will be regular.

toString

java.lang.String toString()

Overrides:

toString in class java.lang.Object

toDataString

java.lang.String toDataString()