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Interface weka.core.converters.Loader
- public interface Loader
- extends java.io.Serializable
Interface to something that can load Instances from an input source in some
format.
- Version:
- $Revision: 1.3 $
- Author:
- Mark Hall (mhall@cs.waikato.ac.nz)
getDataSet()
- Return the full data set.
getNextInstance()
- Read the data set incrementally---get the next instance in the data
set or returns null if there are no
more instances to get.
getStructure()
- Determines and returns (if possible) the structure (internally the
header) of the data set as an empty set of instances.
setSource(File)
- Resets the Loader object and sets the source of the data set to be
the supplied File object.
setSource(InputStream)
- Resets the Loader object and sets the source of the data set to be
the supplied InputStream.
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.
- Parameters:
file
- the File
- Throws:
- java.io.IOException - if an error occurs
support loading from a File.
public_normal_behavior
requires: file != null
&& (* file exists *);
modifiable: model_sourceSupplied, model_structureDetermined;
ensures: model_sourceSupplied == true
&& model_structureDetermined == false;
also
public_exceptional_behavior
requires: file == null
|| (* file does not exist *);
signals: (IOException);
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.
- Parameters:
input
- the source InputStream
- Throws:
- java.io.IOException - if this Loader doesn't
support loading from a File.
getStructure
public Instances getStructure() throws java.io.IOException
Determines and returns (if possible) the structure (internally the
header) of the data set as an empty set of instances.
- 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 Instances getDataSet() throws java.io.IOException
Return the full data set. If the structure hasn't yet been determined
by a call to getStructure then the method should do so before processing
the rest of the data set.
- 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 Instance getNextInstance() throws java.io.IOException
Read the data set incrementally---get the next instance in the data
set or returns null if there are no
more instances to get. If the structure hasn't yet been
determined by a call to getStructure then method should do so before
returning the next instance in the data set.
If it is not possible to read the data set incrementally (ie. in cases
where the data set structure cannot be fully established before all
instances have been seen) then an exception should be thrown.
- 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);
|}
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