weka.core.converters
Class AbstractLoader

java.lang.Object
  |
  +--weka.core.converters.AbstractLoader

All Implemented Interfaces:

Loader, java.io.Serializable

Direct Known Subclasses:

ArffLoader, C45Loader, CSVLoader, SerializedInstancesLoader

public abstract class AbstractLoader

extends java.lang.Object

implements Loader

Abstract class for Loaders that contains default implementation of the setSource methods: Any of these methods that are not overwritten will result in throwing IOException.

Author:

Len Trigg

See Also:

Serialized Form

Field Summary

protected static int	BATCH For representing that instances have been retrieved in batch mode
protected static int	INCREMENTAL For representing that instances have been retrieved incrementally
protected int	m_Retrieval
protected static int	NONE For state where no instances have been retrieved yet

Constructor Summary

AbstractLoader()

Method Summary

abstract Instances	getDataSet() Must be overridden by subclasses.
abstract Instance	getNextInstance() Must be overridden by subclasses.
protected int	getRetrieval()
abstract Instances	getStructure() Must be overridden by subclasses.
protected void	setRetrieval(int mode)
void	setSource(java.io.File file) Resets the Loader object and sets the source of the data set to be the supplied File object.
void	setSource(java.io.InputStream input) Resets the Loader object and sets the source of the data set to be the supplied InputStream.

Methods inherited from class java.lang.Object

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

Field Detail

NONE

protected static final int NONE

For state where no instances have been retrieved yet

BATCH

protected static final int BATCH

For representing that instances have been retrieved in batch mode

INCREMENTAL

protected static final int INCREMENTAL

For representing that instances have been retrieved incrementally

m_Retrieval

protected int m_Retrieval

Constructor Detail

AbstractLoader

public AbstractLoader()

Method Detail

setRetrieval

protected void setRetrieval(int mode)

getRetrieval

protected int getRetrieval()

setSource

public void setSource(java.io.File file)
               throws java.io.IOException

Resets the Loader object and sets the source of the data set to be the supplied File object.

Specified by:

setSource in interface Loader

Parameters:

file - the File.

Throws:

java.io.IOException - always thrown.

setSource

public void setSource(java.io.InputStream input)
               throws java.io.IOException

Resets the Loader object and sets the source of the data set to be the supplied InputStream.

Specified by:

setSource in interface Loader

Parameters:

input - the source InputStream.

Throws:

java.io.IOException - always thrown.

getStructure

public abstract Instances getStructure()
                                throws java.io.IOException

Must be overridden by subclasses.

Specified by:

getStructure in interface Loader

Following copied from interface: weka.core.converters.Loader

Returns:

the structure of the data set as an empty set of Instances

Throws:

java.io.IOException - if there is no source or parsing fails

    public_normal_behavior
      requires: model_sourceSupplied == true
                && model_structureDetermined == false
                && (* successful parse *);
      modifiable: model_structureDetermined;
      ensures: \result != null
               && \result.numInstances() == 0
               && model_structureDetermined == true;
  also
    public_exceptional_behavior
      requires: model_sourceSupplied == false
                || (* unsuccessful parse *);
      signals: (IOException);
 

getDataSet

public abstract Instances getDataSet()
                              throws java.io.IOException

Must be overridden by subclasses.

Specified by:

getDataSet in interface Loader

Following copied from interface: weka.core.converters.Loader

Returns:

the full data set as an Instances object

Throws:

java.io.IOException - if there is an error during parsing or if getNextInstance has been called on this source (either incremental or batch loading can be used, not both).

    public_normal_behavior
      requires: model_sourceSupplied == true
                && (* successful parse *);
      modifiable: model_structureDetermined;
      ensures: \result != null
               && \result.numInstances() >= 0
               && model_structureDetermined == true;
  also
    public_exceptional_behavior
      requires: model_sourceSupplied == false
                || (* unsuccessful parse *);
      signals: (IOException);
 

getNextInstance

public abstract Instance getNextInstance()
                                  throws java.io.IOException

Must be overridden by subclasses.

Specified by:

getNextInstance in interface Loader

Following copied from interface: weka.core.converters.Loader

Returns:

the next instance in the data set as an Instance object or null if there are no more instances to be read

Throws:

java.io.IOException - if there is an error during parsing or if getDataSet has been called on this source (either incremental or batch loading can be used, not both).

    public_normal_behavior
    {|
       requires: model_sourceSupplied == true
                 && (* successful parse *);
       modifiable: model_structureDetermined;
       ensures: model_structureDetermined == true
                && \result != null;
     also
       requires: model_sourceSupplied == true
                 && (* no further input *);
       modifiable: model_structureDetermined;
       ensures: model_structureDetermined == true
                && \result == null;
    |}
  also
    public_exceptional_behavior
    {|
       requires: model_sourceSupplied == false
                 || (* unsuccessful parse *);
       signals: (IOException);
     also
       requires: (* unable to process data set incrementally *);
       signals: (IOException);
    |}