/*
 * File:        NetworkInput.java
 * Author:      Justin Basilico
 * Course:      PO CS 152: Neural Networks
 * Assignment:  Final Project
 * Updated:     2001.12.18
 * Created:     2001.12.03
 *
 * Description:
 * This file contains the NetworkInput interface, which is an interface that
 * describes an Object that is input to a NeuralNetwork.
 *
 * Copyright:    Justin Basilico (2001).
 */

/**
 * NetworkInput interface
 *
 * This interface is for Objects that are used as inputs for a NeuralNetwork.
 * Specifically, it will be used by UnitEncoder objects to encode the
 * NetworkInput into an array of doubles that represent the activation values
 * of the input units in the network.
 *
 * The only methods to be implemented by classes that use this interface are
 * the getProperty() method. There are two versions of the method, one that
 * takes an integer property number and another that takes a String property
 * name. Both of these methods should return an Object which is the specified
 * property. The reason for doing this is so that it can be used along with a
 * UnitEncoder, which should know the proper property that it is retrieving
 * from the NetworkInput that it is to encode. The NetworkInput and
 * UnitEncoder interfaces really act as a pair. There is an integer and String
 * version of the methods so that you can choose which of the two methods to
 * use in order to get the best performance from the specific implementation.
 *
 * @author  Justin Basilico
 * @version 2001.12.18
 * @see     UnitEncoder
 * @see     NeuralNetwork
 * @see     FeedForwardNetwork
 */
public interface NetworkInput
{
    /**
     * getProperty (integer)
     *
     * This method takes an integer property number and returns the Object for
     * this NetworkInput corresponding to that property number. If there is no
     * corresponding Object, it returns null.
     *
     * This method should be used instead of the String version of
     * getProperty() in order to make things slightly faster.
     *
     * @param  propertyNum The integer property number to get from this
     *         NetworkInput.
     * @return The Object for this NetworkInput with the given property
     *         number, or null if there is no such Object.
     * @see    NetworkInput.getProperty(String)
     */
    public Object getProperty(
        int                 propertyNum);       // Property number to get.

    /**
     * getProperty (String)
     *
     * This method takes an String property name and returns the Object for
     * this NetworkInput corresponding to that property name. If there is no
     * corresponding Object, it returns null.
     *
     * This method should be used if the implementing NetworkInput has some
     * sort of Hashtable, otherwise the integer version of the method should
     * probably be used because it is faster.
     *
     * @param  propertyNum The integer property number to get from this
     *         NetworkInput.
     * @return The Object for this NetworkInput with the given property
     *         number, or null if there is no such Object.
     * @see    NetworkInput.getProperty(int)
     */
    public Object getProperty(
        String              propertyName);      // Property name to get.
}