Package weka.core.converters
Interface Loader
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- All Superinterfaces:
RevisionHandler
,java.io.Serializable
- All Known Implementing Classes:
AbstractFileLoader
,AbstractLoader
,ArffLoader
,C45Loader
,CSVLoader
,DatabaseLoader
,LibSVMLoader
,SerializedInstancesLoader
,SVMLightLoader
,TextDirectoryLoader
,XRFFLoader
public interface Loader extends java.io.Serializable, RevisionHandler
Interface to something that can load Instances from an input source in some format.- Version:
- $Revision: 7454 $
- Author:
- Mark Hall (mhall@cs.waikato.ac.nz)
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Field Summary
Fields Modifier and Type Field Description static int
BATCH
static int
INCREMENTAL
static int
NONE
The retrieval modes
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description Instances
getDataSet()
Return the full data set.Instance
getNextInstance(Instances structure)
Read the data set incrementally---get the next instance in the data set or returns null if there are no more instances to get.Instances
getStructure()
Determines and returns (if possible) the structure (internally the header) of the data set as an empty set of instances.void
reset()
Resets the Loader object ready to begin loading.void
setRetrieval(int mode)
Sets the retrieval 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 interface weka.core.RevisionHandler
getRevision
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Field Detail
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NONE
static final int NONE
The retrieval modes- See Also:
- Constant Field Values
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BATCH
static final int BATCH
- See Also:
- Constant Field Values
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INCREMENTAL
static final int INCREMENTAL
- See Also:
- Constant Field Values
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Method Detail
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setRetrieval
void setRetrieval(int mode)
Sets the retrieval mode. Note: Some loaders may not be able to implement incremental loading.- Parameters:
mode
- the retrieval mode
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reset
void reset() throws java.lang.Exception
Resets the Loader object ready to begin loading. If there is an existing source, implementations should attempt to reset in such a fashion as to be able to load from the beginning of the source.- Throws:
java.lang.Exception
- if Loader can't be reset for some reason.
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setSource
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);
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setSource
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.
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getStructure
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 failspublic_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);
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getDataSet
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);
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getNextInstance
Instance getNextInstance(Instances structure) 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.- Parameters:
structure
- the dataset header information, will get updated in case of string or relational attributes- 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).
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