/*
* 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.
*/
/*
* NumericItem.java
* Copyright (C) 2010 University of Waikato, Hamilton, New Zealand
*
*/
package weka.associations;
import java.io.Serializable;
import weka.core.Attribute;
import weka.core.Utils;
/**
* Class that encapsulates a numeric item.
*
* @author Mark Hall (mhall{[at]}pentaho{[dot]}com)
* @version $Revision: 6543 $
*/
public class NumericItem extends Item implements Serializable {
/** For serialization */
private static final long serialVersionUID = -7869433770765864800L;
public static enum Comparison {
NONE,
EQUAL,
LESS_THAN_OR_EQUAL_TO,
GREATER_THAN;
}
/** The numeric test */
protected double m_splitPoint;
/** The comparison operator */
protected Comparison m_comparison;
/**
* Constructs a new <code>NumericItem</code>
*
* @param att the attribute that backs the item.
* @param splitPoint the numeric test value.
* @param comp the comparison operator.
* @throws Exception if the NumericItem can't be constructed.
*/
public NumericItem(Attribute att, double splitPoint, Comparison comp)
throws Exception {
super(att);
if (!att.isNumeric()) {
throw new Exception("NumericItem must be constructed using a numeric attribute");
}
m_comparison = comp;
m_splitPoint = splitPoint;
}
/**
* Gets the numeric test.
*
* @return the numeric test value for this item.
*/
public double getSplitPoint() {
return m_splitPoint;
}
/**
* Gets the comparison operator for this item.
*
* @return the comparison operator for this item.
*/
public Comparison getComparison() {
return m_comparison;
}
/**
* Get this item's value as a String.
*
* @return this item's value as a String.
*/
public String getItemValueAsString() {
return Utils.doubleToString(m_splitPoint, 3);
}
/**
* Get this item's comparison operator as a String.
*
* @return this item's comparison operator as a String.
*/
public String getComparisonAsString() {
String result = null;
switch (m_comparison) {
case EQUAL:
result = "=";
break;
case LESS_THAN_OR_EQUAL_TO:
result = "<=";
break;
case GREATER_THAN:
result = ">";
break;
}
return result;
}
/**
* A string representation of this item, (i.e.
* <attribute name> <comparison operator> <item value>).
* This default implementation just prints the attribute
* name and (optionally) frequency information.
*
* @param freq true if the frequency should be included.
* @return a string representation of this item.
*/
public String toString(boolean freq) {
StringBuffer result = new StringBuffer();
result.append(m_attribute.name() + " ");
switch (m_comparison) {
case EQUAL:
result.append("=");
break;
case LESS_THAN_OR_EQUAL_TO:
result.append("<=");
break;
case GREATER_THAN:
result.append(">");
break;
}
result.append(" " + Utils.doubleToString(m_splitPoint, 4));
if (freq) {
result.append(":" + m_frequency);
}
return result.toString();
}
/**
* Equals. Compares the attribute, numeric test and comparison
* operator
*
* @return true if this NumericItem is equal to the argument.
*/
public boolean equals(Object compareTo) {
if (!(compareTo instanceof NumericItem)) {
return false;
}
NumericItem b = (NumericItem)compareTo;
if (m_attribute.equals(b.getAttribute()) &&
m_comparison == b.getComparison() &&
(new Double(m_splitPoint).equals(new Double(b.getSplitPoint())))) {
return true;
}
return false;
}
}