// File: Herbivore.java from the package edu.colorado.simulations
// Complete documentation is available from the Herbivore link in
// http://www.cs.colorado.edu/~main/docs /
package edu.colorado.simulations;
/******************************************************************************
* A Herbivore is an Animal with extra methods that
* allow it to eat Plant objects.
*
* Java Source Code for this class:
*
* http://www.cs.colorado.edu/~main/edu/colorado/simulations/Herbivore.java
*
*
* @author Michael Main
* (main@colorado.edu)
*
* @version
* Jun 12, 1998
*
* @see Animal
* @see Plant
******************************************************************************/
public class Herbivore extends Animal
{
/**
* Construct an Herbivore with a specified size, growth rate, and
* weekly eating need.
* @param initSize
* the initial size of this Herbivore, in ounces
* @param initRate
* the initial growth rate of this Herbivore, in ounces
* @param initNeed
* the initial weekly eating requirement of this Animal, in
* ounces per week
* Precondition:
* initSize >= 0 and initNeed >= 0.
* Also, if initSize is zero, then
* initRate must also be zero.
* Postcondition:
* This Herbivore has been initialized. The value returned from
* getSize() is now initSize, the value
* returned from getRate() is now initRate, and
* this Herbivore must eat at least initNeed ounces
* of food each week to survive.
* @exception IllegalArgumentException
* Indicates that initSize, initRate, or
* initNeed violates the precondition.
**/
public Herbivore(double initSize, double initRate, double initNeed)
{
super(initSize, initRate, initNeed);
}
/**
* Have this Herbivore eat part of a Plant.
* @param meal
* the Plant that will be partly eaten
* Postcondition:
* Part of the Plant has been eaten by this Herbivore,
* by activating both eat(amount) and
* meal.nibbledOn(amount). The amount is usually
* half of the Plant, but it will not be more than 10% of
* this Herbivore’s weekly need nor more than the amount that
* this Herbivore still needs to eat to survive this week.
**/
public void nibble(Plant meal)
{
final double PORTION = 0.5; // Eat no more than this portion of plant
final double MAX_FRACTION = 0.1; // Eat no more than this fraction of weekly need
double amount; // How many ounces of the plant will be eaten
// Set amount to some portion of the plant, but no more than a given
// maximum fraction of the total weekly need, and no more than what the
// herbivore still needs to eat this week.
amount = PORTION * meal.getSize( );
if (amount > MAX_FRACTION * getNeed( ))
amount = MAX_FRACTION * getNeed( );
if (amount > stillNeed( ))
amount = stillNeed( );
// Eat the plant
eat(amount);
meal.nibbledOn(amount);
}
}