content: /*
   *    This program is free software; you can redistribute it and/or modify
   *    it under the terms of the GNU General Public License as published by
   *    the Free Software Foundation; either version 2 of the License, or
   *    (at your option) any later version.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU General Public License for more details.
   *
   *    You should have received a copy of the GNU General Public License
   *    along with this program; if not, write to the Free Software
   *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  /*
   *    Instance.java
   *    Copyright (C) 1999 University of Waikato, Hamilton, New Zealand
   *
   */
  
  package weka.core;
  
  import java.io.Serializable;
  import java.util.Enumeration;
  import java.util.ArrayList;
  
  /**
   * Interface representing an instance. All values (numeric, date,
   * nominal, string or relational) are internally stored as
   * floating-point numbers in the original concrete class
   * implementations (now called DenseInstance.java and
   * SparseInstance.java), and the methods in this interface reflect
   * this. If an attribute is nominal (or a string or relational), the
   * stored value is the index of the corresponding nominal (or string
   * or relational) value in the attribute's definition. We have chosen
   * this approach in favor of a more elegant object-oriented approach
   * because it is much faster. <p>
   *
   * Typical usage (code from the main() method of this class): <p>
   *
   * <code>
   * ... <br>
   *      
   * // Create empty instance with three attribute values <br>
   * Instance inst = new DenseInstance(3); <br><br>
   *     
   * // Set instance's values for the attributes "length", "weight", and "position"<br>
   * inst.setValue(length, 5.3); <br>
   * inst.setValue(weight, 300); <br>
   * inst.setValue(position, "first"); <br><br>
   *   
   * // Set instance's dataset to be the dataset "race" <br>
   * inst.setDataset(race); <br><br>
   *   
   * // Print the instance <br>
   * System.out.println("The instance: " + inst); <br>
   *
   * ... <br>
   * </code><p>
   *
   * All methods that change an instance's attribute values must be
   * safe, ie. a change of an instance's attribute values must not
   * affect any other instances.
   *
   * @author Eibe Frank (eibe@cs.waikato.ac.nz)
   * @version $Revision: 5987 $ 
   */
  public interface Instance extends Copyable {
  
    /**
     * Returns the attribute with the given index.
     *
     * @param index the attribute's index
     * @return the attribute at the given position
     * @throws UnassignedDatasetException if instance doesn't have access to a
     * dataset
     */ 
    public Attribute attribute(int index);
  
    /**
     * Returns the attribute with the given index in the sparse representation.
     * Same as attribute(int) for a DenseInstance.
     *
     * @param indexOfIndex the index of the attribute's index 
     * @return the attribute at the given position
     * @throws UnassignedDatasetException if instance doesn't have access to a
     * dataset
     */ 
    public Attribute attributeSparse(int indexOfIndex);
  
    /**
     * Returns class attribute.
     *
     * @return the class attribute
     * @throws UnassignedDatasetException if the class is not set or the
     * instance doesn't have access to a dataset
     */
    public Attribute classAttribute();
  
    /**
     * Returns the class attribute's index.
     *
     * @return the class index as an integer 
     * @throws UnassignedDatasetException if instance doesn't have access to a dataset 
     */
    public int classIndex();
  
    /**
     * Tests if an instance's class is missing.
     *
     * @return true if the instance's class is missing
     * @throws UnassignedClassException if the class is not set or the instance doesn't
     * have access to a dataset
     */
    public boolean classIsMissing();
  
    /**
     * Returns an instance's class value as a floating-point number.
     *
     * @return the corresponding value as a double (If the 
     * corresponding attribute is nominal (or a string) then it returns the 
     * value's index as a double).
     * @throws UnassignedClassException if the class is not set or the instance doesn't
     * have access to a dataset 
     */
    public double classValue();
  
    /**
     * Returns the dataset this instance has access to. (ie. obtains
     * information about attribute types from) Null if the instance
     * doesn't have access to a dataset.
     *
     * @return the dataset the instance has accesss to
     */
    public Instances dataset();
  
    /**
     * Deletes an attribute at the given position (0 to 
     * numAttributes() - 1). Only succeeds if the instance does not
     * have access to any dataset because otherwise inconsistencies
     * could be introduced.
     *
     * @param position the attribute's position
     * @throws RuntimeException if the instance has access to a
     * dataset 
     */
    public void deleteAttributeAt(int position);
  
    /**
     * Returns an enumeration of all the attributes.
     *
     * @return enumeration of all the attributes
     * @throws UnassignedDatasetException if the instance doesn't
     * have access to a dataset 
     */
    public Enumeration enumerateAttributes();
  
    /**
     * Tests if the headers of two instances are equivalent.
     *
     * @param inst another instance
     * @return true if the header of the given instance is 
     * equivalent to this instance's header
     * @throws UnassignedDatasetException if instance doesn't have access to any
     * dataset
     */
    public boolean equalHeaders(Instance inst);
  
    /**
     * Checks if the headers of two instances are equivalent. 
     * If not, then returns a message why they differ.
     *
     * @param dataset 	another instance
     * @return 		null if the header of the given instance is equivalent 
     * 			to this instance's header, otherwise a message with details on
     * 			why they differ
     */
    public String equalHeadersMsg(Instance inst);
  
    /**
     * Tests whether an instance has a missing value. Skips the class attribute if set.
     * @return true if instance has a missing value.
     * @throws UnassignedDatasetException if instance doesn't have access to any
     * dataset
     */
    public boolean hasMissingValue();
  
    /**
     * Returns the index of the attribute stored at the given position in the sparse
     * representation. Identify function for an instance of type DenseInstance.
     *
     * @param position the position 
     * @return the index of the attribute stored at the given position
     */
    public int index(int position);
  
    /**
     * Inserts an attribute at the given position (0 to 
     * numAttributes()). Only succeeds if the instance does not
     * have access to any dataset because otherwise inconsistencies
     * could be introduced.
     *
     * @param position the attribute's position
     * @throws RuntimeException if the instance has accesss to a
     * dataset
     * @throws IllegalArgumentException if the position is out of range
     */
    public void insertAttributeAt(int position);
  
    /**
     * Tests if a specific value is "missing".
     *
     * @param attIndex the attribute's index
     * @return true if the value is "missing"
     */
    public boolean isMissing(int attIndex);
  
    /**
     * Tests if a specific value is "missing" in the sparse
     * representation. Samse as isMissing(int) for a DenseInstance.
     *
     * @param indexOfIndex the index of the attribute's index 
     * @return true if the value is "missing"
     */
    public boolean isMissingSparse(int indexOfIndex);
  
    /**
     * Tests if a specific value is "missing".
     * The given attribute has to belong to a dataset.
     *
     * @param att the attribute
     * @return true if the value is "missing"
     */
    public boolean isMissing(Attribute att);
  
    /**
     * Merges this instance with the given instance and returns
     * the result. Dataset is set to null. The returned instance
     * is of the same type as this instance.
     *
     * @param inst the instance to be merged with this one
     * @return the merged instances
     */
    public Instance mergeInstance(Instance inst);
  
    /**
     * Returns the number of attributes.
     *
     * @return the number of attributes as an integer
     */
    public int numAttributes();
  
    /**
     * Returns the number of class labels.
     *
     * @return the number of class labels as an integer if the 
     * class attribute is nominal, 1 otherwise.
     * @throws UnassignedDatasetException if instance doesn't have access to any
     * dataset
     */
    public int numClasses();
  
    /**
     * Returns the number of values present in a sparse representation.
     *
     * @return the number of values
     */
    public int numValues();
  
    /** 
     * Replaces all missing values in the instance with the
     * values contained in the given array. A deep copy of
     * the vector of attribute values is performed before the
     * values are replaced.
     *
     * @param array containing the means and modes
     * @throws IllegalArgumentException if numbers of attributes are unequal
     */
    public void replaceMissingValues(double[] array);
  
    /**
     * Sets the class value of an instance to be "missing". A deep copy of
     * the vector of attribute values is performed before the
     * value is set to be missing.
     *
     * @throws UnassignedClassException if the class is not set
     * @throws UnassignedDatasetException if the instance doesn't
     * have access to a dataset
     */
    public void setClassMissing();
  
    /**
     * Sets the class value of an instance to the given value (internal
     * floating-point format).  A deep copy of the vector of attribute
     * values is performed before the value is set.
     *
     * @param value the new attribute value (If the corresponding
     * attribute is nominal (or a string) then this is the new value's
     * index as a double).  
     * @throws UnassignedClassException if the class is not set
     * @throws UnaddignedDatasetException if the instance doesn't
     * have access to a dataset 
     */
    public void setClassValue(double value);
  
    /**
     * Sets the class value of an instance to the given value. A deep
     * copy of the vector of attribute values is performed before the
     * value is set.
     *
     * @param value the new class value (If the class
     * is a string attribute and the value can't be found,
     * the value is added to the attribute).
     * @throws UnassignedClassException if the class is not set
     * @throws UnassignedDatasetException if the dataset is not set
     * @throws IllegalArgumentException if the attribute is not
     * nominal or a string, or the value couldn't be found for a nominal
     * attribute 
     */
    public void setClassValue(String value);
  
    /**
     * Sets the reference to the dataset. Does not check if the instance
     * is compatible with the dataset. Note: the dataset does not know
     * about this instance. If the structure of the dataset's header
     * gets changed, this instance will not be adjusted automatically.
     *
     * @param instances the reference to the dataset 
     */
    public void setDataset(Instances instances);
  
    /**
     * Sets a specific value to be "missing". Performs a deep copy
     * of the vector of attribute values before the value is set to
     * be missing.
     *
     * @param attIndex the attribute's index
     */
    public void setMissing(int attIndex);
  
    /**
     * Sets a specific value to be "missing". Performs a deep copy
     * of the vector of attribute values before the value is set to
     * be missing. The given attribute has to belong to a dataset.
     *
     * @param att the attribute
     */
    public void setMissing(Attribute att);
  
    /**
     * Sets a specific value in the instance to the given value 
     * (internal floating-point format). Performs a deep copy
     * of the vector of attribute values before the value is set.
     *
     * @param attIndex the attribute's index 
     * @param value the new attribute value (If the corresponding
     * attribute is nominal (or a string) then this is the new value's
     * index as a double).  
     */
    public void setValue(int attIndex, double value);
  
    /**
     * Sets a specific value in the instance to the given value
     * (internal floating-point format), given an index into the sparse
     * representation. Performs a deep copy of the vector of attribute
     * values before the value is set. Same as setValue(int, double)
     * for a DenseInstance.
     *
     * @param indexOfIndex the index of the attribute's index 
     * @param value the new attribute value (If the corresponding
     * attribute is nominal (or a string) then this is the new value's
     * index as a double).  
     */
    public void setValueSparse(int indexOfIndex, double value);
  
    /**
     * Sets a value of a nominal or string attribute to the given
     * value. Performs a deep copy of the vector of attribute values
     * before the value is set.
     *
     * @param attIndex the attribute's index
     * @param value the new attribute value (If the attribute
     * is a string attribute and the value can't be found,
     * the value is added to the attribute).
     * @throws UnassignedDatasetException if the dataset is not set
     * @throws IllegalArgumentException if the selected
     * attribute is not nominal or a string, or the supplied value couldn't 
     * be found for a nominal attribute 
     */
    public void setValue(int attIndex, String value);
  
    /**
     * Sets a specific value in the instance to the given value
     * (internal floating-point format). Performs a deep copy of the
     * vector of attribute values before the value is set, so if you are
     * planning on calling setValue many times it may be faster to
     * create a new instance using toDoubleArray.  The given attribute
     * has to belong to a dataset.
     *
     * @param att the attribute 
     * @param value the new attribute value (If the corresponding
     * attribute is nominal (or a string) then this is the new value's
     * index as a double).  
     */
    public void setValue(Attribute att, double value);
  
    /**
     * Sets a value of an nominal or string attribute to the given
     * value. Performs a deep copy of the vector of attribute values
     * before the value is set, so if you are planning on calling setValue many
     * times it may be faster to create a new instance using toDoubleArray.
     * The given attribute has to belong to a dataset.
     *
     * @param att the attribute
     * @param value the new attribute value (If the attribute
     * is a string attribute and the value can't be found,
     * the value is added to the attribute).
     * @throws IllegalArgumentException if the the attribute is not
     * nominal or a string, or the value couldn't be found for a nominal
     * attribute 
     */
    public void setValue(Attribute att, String value);
    
    /**
     * Sets the weight of an instance.
     *
     * @param weight the weight
     */
    public void setWeight(double weight);
  
    /** 
     * Returns the relational value of a relational attribute.
     *
     * @param attIndex the attribute's index
     * @return the corresponding relation as an Instances object
     * @throws IllegalArgumentException if the attribute is not a
     * relation-valued attribute
     * @throws UnassignedDatasetException if the instance doesn't belong
     * to a dataset.
     */
    public Instances relationalValue(int attIndex);
  
  
    /** 
     * Returns the relational value of a relational attribute.
     *
     * @param att the attribute
     * @return the corresponding relation as an Instances object
     * @throws IllegalArgumentException if the attribute is not a
     * relation-valued attribute
     * @throws UnassignedDatasetException if the instance doesn't belong
     * to a dataset.
     */
    public Instances relationalValue(Attribute att);
  
    /** 
     * Returns the value of a nominal, string, date, or relational attribute
     * for the instance as a string.
     *
     * @param attIndex the attribute's index
     * @return the value as a string
     * @throws IllegalArgumentException if the attribute is not a nominal,
     * string, date, or relation-valued attribute.
     * @throws UnassignedDatasetException if the instance doesn't belong
     * to a dataset.
     */
    public String stringValue(int attIndex);
  
    /** 
     * Returns the value of a nominal, string, date, or relational attribute
     * for the instance as a string.
     *
     * @param att the attribute
     * @return the value as a string
     * @throws IllegalArgumentException if the attribute is not a nominal,
     * string, date, or relation-valued attribute.
     * @throws UnassignedDatasetException if the instance doesn't belong
     * to a dataset.
     */
    public String stringValue(Attribute att);
  
    /**
     * Returns the values of each attribute as an array of doubles.
     *
     * @return an array containing all the instance attribute values
     */
    public double[] toDoubleArray();
  
    /**
     * Returns the description of one instance (without weight
     * appended). If the instance
     * doesn't have access to a dataset, it returns the internal
     * floating-point values. Quotes string
     * values that contain whitespace characters.
     *
     * This method is used by getRandomNumberGenerator() in
     * Instances.java in order to maintain backwards compatibility
     * with weka 3.4.
     *
     * @return the instance's description as a string
     */
    public String toStringNoWeight();
  
    /**
     * Returns the description of one value of the instance as a 
     * string. If the instance doesn't have access to a dataset, it 
     * returns the internal floating-point value. Quotes string
     * values that contain whitespace characters, or if they
     * are a question mark.
     *
     * @param attIndex the attribute's index
     * @return the value's description as a string
     */
    public String toString(int attIndex);
  
    /**
     * Returns the description of one value of the instance as a 
     * string. If the instance doesn't have access to a dataset it 
     * returns the internal floating-point value. Quotes string
     * values that contain whitespace characters, or if they
     * are a question mark.
     * The given attribute has to belong to a dataset.
     *
     * @param att the attribute
     * @return the value's description as a string
     */
    public String toString(Attribute att);
  
    /**
     * Returns an instance's attribute value in internal format.
     *
     * @param attIndex the attribute's index
     * @return the specified value as a double (If the corresponding
     * attribute is nominal (or a string) then it returns the value's index as a 
     * double).
     */
    public double value(int attIndex);
  
    /**
     * Returns an instance's attribute value in internal format, given
     * an index in the sparse representation. Same as value(int) for
     * a DenseInstance.
     *
     * @param indexOfIndex the index of the attribute's index
     * @return the specified value as a double (If the corresponding
     * attribute is nominal (or a string) then it returns the value's index as a 
     * double).
     */
    public double valueSparse(int indexOfIndex);
  
    /**
     * Returns an instance's attribute value in internal format.
     * The given attribute has to belong to a dataset.
     *
     * @param att the attribute
     * @return the specified value as a double (If the corresponding
     * attribute is nominal (or a string) then it returns the value's index as a
     * double).
     */
    public double value(Attribute att);
  
    /**
     * Returns the instance's weight.
     *
     * @return the instance's weight as a double
     */
    public double weight();
  }
  