/*
 * Created on Apr 9, 2005
 *
 */
package aima.learning.framework;

import java.util.Hashtable;

public class Example {
	Hashtable<String, Attribute> attributes;

	private Attribute targetAttribute;

	public Example(Hashtable<String, Attribute> attributes,
			Attribute targetAttribute) {
		this.attributes = attributes;
		this.targetAttribute = targetAttribute;
	}

	public String getAttributeValueAsString(String attributeName) {
		return attributes.get(attributeName).valueAsString();
	}
	
	public double getAttributeValueAsDouble(String attributeName) {
		Attribute attribute =  attributes.get(attributeName);
		if(attribute == null || !(attribute instanceof NumericAttribute) ){
			throw new RuntimeException("cannot return numerical value for non numeric attribute");
		}
		return ((NumericAttribute)attribute).valueAsDouble();
	}
	public String toString() {
		return attributes.toString();
	}

	public String targetValue() {
		return getAttributeValueAsString(targetAttribute.name());
	}

	public boolean equals(Object o) {
		if (this == o) {
			return true;
		}
		if ((o == null) || (this.getClass() != o.getClass())) {
			return false;
		}
		Example other = (Example) o;
		return attributes.equals(other.attributes);
	}

	public int hashCode() {
		return attributes.hashCode();
	}

	public Example numerize(Hashtable<String, Hashtable<String, Integer>> attrValueToNumber) {
		Hashtable<String,Attribute> numerizedExampleData = new Hashtable<String,Attribute>();
		for (String key : attributes.keySet()){
			Attribute attribute = attributes.get(key);
			if ( attribute instanceof StringAttribute){
				int correspondingNumber = attrValueToNumber.get(key).get(attribute.valueAsString());
				NumericAttributeSpecification spec = new NumericAttributeSpecification(key);
				numerizedExampleData.put(key,new NumericAttribute((double)correspondingNumber,spec));
			}
			else {//Numeric Attribute
				numerizedExampleData.put(key,attribute);
			}
		}
		return new Example(numerizedExampleData,numerizedExampleData.get(targetAttribute.name()));
	}
}