/*
* File: DefaultBooleanToNumberConverter.java
* Authors: Justin Basilico
* Company: Sandia National Laboratories
* Project: Cognitive Foundry
*
* Copyright June 02, 2008, Sandia Corporation.
* Under the terms of Contract DE-AC04-94AL85000, there is a non-exclusive
* license for use of this work by or on behalf of the U.S. Government. Export
* of this program may require a license from the United States Government.
* See CopyrightHistory.txt for complete details.
*
*/
package gov.sandia.cognition.data.convert.number;
import gov.sandia.cognition.data.convert.AbstractReverseCachedDataConverter;
import gov.sandia.cognition.data.convert.AbstractReversibleDataConverter;
/**
* Converts a {@code Boolean} to a {@code Number} by using predefined values
* for true, false, and (optionally) null.
*
* @author Justin Basilico
* @since 3.0
*/
public class DefaultBooleanToNumberConverter
extends AbstractReverseCachedDataConverter<Boolean, Number, DefaultBooleanToNumberConverter.Reverse>
{
/** The default value for true is {@value}. */
public static final double DEFAULT_TRUE_VALUE = +1.0;
/** The default value for false is {@value}. */
public static final double DEFAULT_FALSE_VALUE = -1.0;
/** The default value for null is {@value}. */
public static final double DEFAULT_NULL_VALUE = 0.0;
/** The number to use to represent a true value. */
protected Number trueValue;
/** The number to use to represent a false value. */
protected Number falseValue;
/** The number to use to represent a null value. */
protected Number nullValue;
/**
* Creates a new {@code DefaultBooleanToNumberConverter} with default values.
*/
public DefaultBooleanToNumberConverter()
{
this(DEFAULT_TRUE_VALUE, DEFAULT_FALSE_VALUE, DEFAULT_NULL_VALUE);
}
/**
* Creates a new {@code DefaultBooleanToNumberConverter}.
*
* @param trueValue The number to use for true.
* @param falseValue The number to use for false.
* @param nullValue The number to use for null.
*/
public DefaultBooleanToNumberConverter(
final Number trueValue,
final Number falseValue,
final Number nullValue)
{
super();
this.trueValue = trueValue;
this.falseValue = falseValue;
this.nullValue = nullValue;
}
/**
* Converts an input boolean to a number.
*
* @param input
* The input value to convert.
* @return
* The boolean converted to a number.
*/
public Number evaluate(
final Boolean input)
{
return this.convertToNumber(input);
}
/**
* Converts the given boolean to a number using the
*
* @param input
* The input boolean to convert to a number.
* @return
* The number value for the boolean.
*/
public Number convertToNumber(
final Boolean input)
{
if (input == null)
{
return this.getNullValue();
}
else if (input.booleanValue())
{
return this.getTrueValue();
}
else
{
return this.getFalseValue();
}
}
/**
* Converts the given number to a boolean value by determining if it is
* closer to the number representing true or the number representing false.
*
* @param input
* The input number to convert to a boolean.
* @return
* The boolean value of the number.
*/
public Boolean convertToBoolean(
final Number input)
{
if (input == null)
{
return null;
}
final double value = input.doubleValue();
if (this.nullValue != null && this.nullValue.equals(value))
{
// TODO: Handle the case where someone is treating null as true or false
// automatically.
return null;
}
// TODO: Cache the double value.
else if (Math.abs(value - this.trueValue.doubleValue()) <=
Math.abs(value - this.falseValue.doubleValue()))
{
return true;
}
else
{
return false;
}
}
@Override
protected DefaultBooleanToNumberConverter.Reverse createReverse()
{
return new Reverse();
}
/**
* Gets the number that represents a true value.
*
* @return The number that represents a true value.
*/
public Number getTrueValue()
{
return this.trueValue;
}
/**
* Sets the number that represents a true value.
*
* @param trueValue
* The number that represents a true value.
*/
public void setTrueValue(
final Number trueValue)
{
this.trueValue = trueValue;
}
/**
* Gets the number that represents a falue value.
*
* @return The number that represents a false value.
*/
public Number getFalseValue()
{
return this.falseValue;
}
/**
* Sets the number that represents a falue value.
*
* @param falseValue The number that represents a false value.
*/
public void setFalseValue(
final Number falseValue)
{
this.falseValue = falseValue;
}
/**
* Gets the number that represents a null value.
*
* @return The number that represents a null value.
*/
public Number getNullValue()
{
return this.nullValue;
}
/**
* Sets the number that represents a null value.
*
* @param nullValue The number that represents a null value.
*/
public void setNullValue(
final Number nullValue)
{
this.nullValue = nullValue;
}
/**
* The reverse converter for the {@code DefaultBooleanToNumberConverter}.
*/
public class Reverse
extends AbstractReversibleDataConverter<Number, Boolean>
{
/**
* Creates a new reverse converter for the
* {@code DefaultBooleanToNumberConverter}.
*/
public Reverse()
{
super();
}
/**
* Converts the given number to a boolean.
*
* @param input
* The input number to convert.
* @return
* The boolean whose number representation is closest:
* true or false.
*/
public Boolean evaluate(
final Number input)
{
return convertToBoolean(input);
}
/**
* Reverses the converter, which is the original converter.
*
* @return The original {@code DefaultBooleanToNumberConverter}.
*/
public DefaultBooleanToNumberConverter reverse()
{
return DefaultBooleanToNumberConverter.this;
}
}
}