ArffLoader.ArffReader (weka-stable 3.6.8 API)

java.lang.Object
- weka.core.converters.ArffLoader.ArffReader

All Implemented Interfaces:: RevisionHandler

Enclosing class:: ArffLoader

public static class ArffLoader.ArffReader
extends Object
implements RevisionHandler

Reads data from an ARFF file, either in incremental or batch mode.

Typical code for batch usage:

 BufferedReader reader = new BufferedReader(new FileReader("/some/where/file.arff"));
 ArffReader arff = new ArffReader(reader);
 Instances data = arff.getData();
 data.setClassIndex(data.numAttributes() - 1);

Typical code for incremental usage:

 BufferedReader reader = new BufferedReader(new FileReader("/some/where/file.arff"));
 ArffReader arff = new ArffReader(reader, 1000);
 Instances data = arff.getStructure();
 data.setClassIndex(data.numAttributes() - 1);
 Instance inst;
 while ((inst = arff.readInstance(data)) != null) {
   data.add(inst);
 }

Version:: $Revision: 7703 $
Author:: Eibe Frank (eibe@cs.waikato.ac.nz), Len Trigg (trigg@cs.waikato.ac.nz), fracpete (fracpete at waikato dot ac dot nz)

Field Summary

Fields
Modifier and Type	Field and Description
`protected Instances`	`m_Data` the actual data
`protected int[]`	`m_IndicesBuffer` Buffer of indices for sparse instance
`protected int`	`m_Lines` the number of lines read so far
`protected StreamTokenizer`	`m_Tokenizer` the tokenizer for reading the stream
`protected double[]`	`m_ValueBuffer` Buffer of values for sparse instance

Constructor Summary

Constructors
Constructor and Description
`ArffReader(Reader reader)` Reads the data completely from the reader.
`ArffReader(Reader reader, Instances template, int lines)` Reads the data without header according to the specified template.
`ArffReader(Reader reader, Instances template, int lines, int capacity)` Initializes the reader without reading the header according to the specified template.
`ArffReader(Reader reader, int capacity)` Reads only the header and reserves the specified space for instances.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected void`	`compactify()` compactifies the data
`protected void`	`errorMessage(String msg)` Throws error message with line number and last token read.
`Instances`	`getData()` Returns the data that was read
`protected void`	`getFirstToken()` Gets next token, skipping empty lines.
`protected void`	`getIndex()` Gets index, checking for a premature and of line.
`protected Instance`	`getInstance(Instances structure, boolean flag)` Reads a single instance using the tokenizer and returns it.
`protected Instance`	`getInstanceFull(boolean flag)` Reads a single instance using the tokenizer and returns it.
`protected Instance`	`getInstanceSparse(boolean flag)` Reads a single instance using the tokenizer and returns it.
`protected double`	`getInstanceWeight()` Gets the value of an instance's weight (if one exists)
`protected void`	`getLastToken(boolean endOfFileOk)` Gets token and checks if its end of line.
`int`	`getLineNo()` returns the current line number
`protected void`	`getNextToken()` Gets next token, checking for a premature and of line.
`String`	`getRevision()` Returns the revision string.
`Instances`	`getStructure()` Returns the header format
`protected void`	`initBuffers()` initializes the buffers for sparse instances to be read
`protected void`	`initTokenizer()` Initializes the StreamTokenizer used for reading the ARFF file.
`protected FastVector`	`parseAttribute(FastVector attributes)` Parses the attribute declaration.
`protected void`	`readHeader(int capacity)` Reads and stores header of an ARFF file.
`Instance`	`readInstance(Instances structure)` Reads a single instance using the tokenizer and returns it.
`Instance`	`readInstance(Instances structure, boolean flag)` Reads a single instance using the tokenizer and returns it.
`protected void`	`readTillEOL()` Reads and skips all tokens before next end of line token.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - m_Tokenizer
```
protected StreamTokenizer m_Tokenizer
```
    the tokenizer for reading the stream
  - m_ValueBuffer
```
protected double[] m_ValueBuffer
```
    Buffer of values for sparse instance
  - m_IndicesBuffer
```
protected int[] m_IndicesBuffer
```
    Buffer of indices for sparse instance
  - m_Data
```
protected Instances m_Data
```
    the actual data
  - m_Lines
```
protected int m_Lines
```
    the number of lines read so far
- Constructor Detail
  - ArffReader
```
public ArffReader(Reader reader)
           throws IOException
```
    Reads the data completely from the reader. The data can be accessed via the getData() method.
    
    Parameters:
    
    reader - the reader to use
    
    Throws:
    
    IOException - if something goes wrong
    
    See Also:
    
    getData()
  - ArffReader
```
public ArffReader(Reader reader,
                  int capacity)
           throws IOException
```
    Reads only the header and reserves the specified space for instances. Further instances can be read via readInstance().
    
    Parameters:
    
    reader - the reader to use
    
    capacity - the capacity of the new dataset
    
    Throws:
    
    IOException - if something goes wrong
    
    IllegalArgumentException - if capacity is negative
    
    See Also:
    
    getStructure(), readInstance(Instances)
  - ArffReader
```
public ArffReader(Reader reader,
                  Instances template,
                  int lines)
           throws IOException
```
    Reads the data without header according to the specified template. The data can be accessed via the getData() method.
    
    Parameters:
    
    reader - the reader to use
    
    template - the template header
    
    lines - the lines read so far
    
    Throws:
    
    IOException - if something goes wrong
    
    See Also:
    
    getData()
  - ArffReader
```
public ArffReader(Reader reader,
                  Instances template,
                  int lines,
                  int capacity)
           throws IOException
```
    Initializes the reader without reading the header according to the specified template. The data must be read via the readInstance() method.
    
    Parameters:
    
    reader - the reader to use
    
    template - the template header
    
    lines - the lines read so far
    
    capacity - the capacity of the new dataset
    
    Throws:
    
    IOException - if something goes wrong
    
    See Also:
    
    getData()
- Method Detail
  - initBuffers
```
protected void initBuffers()
```
    initializes the buffers for sparse instances to be read
    
    See Also:
    
    m_ValueBuffer, m_IndicesBuffer
  - compactify
```
protected void compactify()
```
    compactifies the data
  - errorMessage
```
protected void errorMessage(String msg)
                     throws IOException
```
    Throws error message with line number and last token read.
    
    Parameters:
    
    msg - the error message to be thrown
    
    Throws:
    
    IOException - containing the error message
  - getLineNo
```
public int getLineNo()
```
    returns the current line number
    
    Returns:
    
    the current line number
  - getFirstToken
```
protected void getFirstToken()
                      throws IOException
```
    Gets next token, skipping empty lines.
    
    Throws:
    
    IOException - if reading the next token fails
  - getIndex
```
protected void getIndex()
                 throws IOException
```
    Gets index, checking for a premature and of line.
    
    Throws:
    
    IOException - if it finds a premature end of line
  - getLastToken
```
protected void getLastToken(boolean endOfFileOk)
                     throws IOException
```
    Gets token and checks if its end of line.
    
    Parameters:
    
    endOfFileOk - whether EOF is OK
    
    Throws:
    
    IOException - if it doesn't find an end of line
  - getInstanceWeight
```
protected double getInstanceWeight()
                            throws IOException
```
    Gets the value of an instance's weight (if one exists)
    
    Returns:
    
    the value of the instance's weight, or NaN if no weight has been supplied in the file
    
    Throws:
    
    IOException
  - getNextToken
```
protected void getNextToken()
                     throws IOException
```
    Gets next token, checking for a premature and of line.
    
    Throws:
    
    IOException - if it finds a premature end of line
  - initTokenizer
```
protected void initTokenizer()
```
    Initializes the StreamTokenizer used for reading the ARFF file.
  - readInstance
```
public Instance readInstance(Instances structure)
                      throws IOException
```
    Reads a single instance using the tokenizer and returns it.
    
    Parameters:
    
    structure - the dataset header information, will get updated in case of string or relational attributes
    
    Returns:
    
    null if end of file has been reached
    
    Throws:
    
    IOException - if the information is not read successfully
  - readInstance
```
public Instance readInstance(Instances structure,
                             boolean flag)
                      throws IOException
```
    Reads a single instance using the tokenizer and returns it.
    
    Parameters:
    
    structure - the dataset header information, will get updated in case of string or relational attributes
    
    flag - if method should test for carriage return after each instance
    
    Returns:
    
    null if end of file has been reached
    
    Throws:
    
    IOException - if the information is not read successfully
  - getInstance
```
protected Instance getInstance(Instances structure,
                               boolean flag)
                        throws IOException
```
    Reads a single instance using the tokenizer and returns it.
    
    Parameters:
    
    structure - the dataset header information, will get updated in case of string or relational attributes
    
    flag - if method should test for carriage return after each instance
    
    Returns:
    
    null if end of file has been reached
    
    Throws:
    
    IOException - if the information is not read successfully
  - getInstanceSparse
```
protected Instance getInstanceSparse(boolean flag)
                              throws IOException
```
    Reads a single instance using the tokenizer and returns it.
    
    Parameters:
    
    flag - if method should test for carriage return after each instance
    
    Returns:
    
    null if end of file has been reached
    
    Throws:
    
    IOException - if the information is not read successfully
  - getInstanceFull
```
protected Instance getInstanceFull(boolean flag)
                            throws IOException
```
    Reads a single instance using the tokenizer and returns it.
    
    Parameters:
    
    flag - if method should test for carriage return after each instance
    
    Returns:
    
    null if end of file has been reached
    
    Throws:
    
    IOException - if the information is not read successfully
  - readHeader
```
protected void readHeader(int capacity)
                   throws IOException
```
    Reads and stores header of an ARFF file.
    
    Parameters:
    
    capacity - the number of instances to reserve in the data structure
    
    Throws:
    
    IOException - if the information is not read successfully
  - parseAttribute
```
protected FastVector parseAttribute(FastVector attributes)
                             throws IOException
```
    Parses the attribute declaration.
    
    Parameters:
    
    attributes - the current attributes vector
    
    Returns:
    
    the new attributes vector
    
    Throws:
    
    IOException - if the information is not read successfully
  - readTillEOL
```
protected void readTillEOL()
                    throws IOException
```
    Reads and skips all tokens before next end of line token.
    
    Throws:
    
    IOException - in case something goes wrong
  - getStructure
```
public Instances getStructure()
```
    Returns the header format
    
    Returns:
    
    the header format
  - getData
```
public Instances getData()
```
    Returns the data that was read
    
    Returns:
    
    the data
  - getRevision
```
public String getRevision()
```
    Returns the revision string.
    
    Specified by:
    
    getRevision in interface RevisionHandler
    
    Returns:
    
    the revision

Class ArffLoader.ArffReader

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

m_Tokenizer

m_ValueBuffer

m_IndicesBuffer

m_Data

m_Lines

Constructor Detail

ArffReader

ArffReader

ArffReader

ArffReader

Method Detail

initBuffers

compactify

errorMessage

getLineNo

getFirstToken

getIndex

getLastToken

getInstanceWeight

getNextToken

initTokenizer

readInstance

readInstance

getInstance

getInstanceSparse

getInstanceFull

readHeader

parseAttribute

readTillEOL

getStructure

getData

getRevision