catfish.java

ssd1 e5............................................

/**
 * Basic Catfish - simulates a catfish - can swim and consume energy in the process.
 * 
 * @author  A JiaYi
 * @version 1.0.0
 * Created on 2005-5-4
 */

import java.util.*;

public class Catfish extends LivingBeing {

	/**
	 * The catfish is born "alive". 
	 * Then it dies, becoming a corpse. 
	 */
	private String ALIVE = "alive";

	/**
	 * The catfish is born "alive". 
	 * Then it dies, becoming a "dead" corpse. 
	 */
	private String DEAD = "dead";

	/**
	 * Energy needed to swim in a block of time.
	 */
	private int ENERGY_TO_SWIM = 2;
			
	/**
	 * Row-wise location of the catfish
	 */
	private int row;

	/**
	 * Column-wise location of the catfish
	 */
	private int column;

	/**
	 * Image of the catfish - is really a filename
	 */
	private String imageFileName;

	/**
	 * Is the catfish dead or alive?
	 */
	private String deadOrAlive;

	/**
	 * Age expressed as blocks of time lived
	 */
	private int age;
	private int energy;

	/**
	 * The simulation to which this catfish belongs.
	 * This is needed so the catfish can send a message 
	 * to simulation.
	 */
	private Simulation simulation;

	/**
	 * Constructor. Initialize a catfish to start life at a specified 
	 * location with a specified energy. If location is out of bounds,
	 * locate the catfish at the nearest edge.
	 * 
	 * @param initialRow - the row at which the catfish is located
	 * @param initialColumn - the column at which the catfish is located
	 * @param initialSimulation - the simulation that the catfish belongs to
	 */
	public Catfish(
		int initialRow,
		int initialColumn,
		Simulation initialSimulation) {

			simulation = initialSimulation;

			deadOrAlive = ALIVE; 	

			age = 0;
			energy = 10;		
			
			imageFileName = "/Catfish-right.gif";	

			row = initialRow;
			column = initialColumn;
	}
	
	/**
	 * Get the row at which the catfish is located 
	 * 
	 * @return - the row of the catfish's location. 
	 */		
	public int getRow() {
		return row;
	}

	/**
	 * Get the column at which the catfish is located
	 * 
	 * @return - the column of the catfish's location. 
	 */		
	public int getColumn() {
		return column;
	}

	/**
	 * get filename of catfish image
	 * 
	 * @return filename of Catfish image
	 */
	public String getImage() {
		return imageFileName;
	}

	/**
	 * Get the catfish's age
	 * 
	 * @return the age of the catfish expressed in blocks of time
	 */
	public int getAge() {
		// Student:Please complete this method.
                return age;
	}

	/**
	 * Get the energy of the catfish
	 * 
	 * @return current energy level of the catfish
	 */
	public int getEnergy() {
		// Student:Please complete this method.
                return energy;
	}

	/**
	 * Die: The Catfish dies.
	 */
	public void die() {
		// Student:Please complete this method.	
		// Set the deadOrAlive attribute to indicate that the catfish is dead.
                deadOrAlive = DEAD; 
	}

	/**
	 * Is the catfish dead?
	 * 
	 * @return <code>true</code> if dead. <code>false</code>, otherwise.
	 */
	public boolean isDead() {
		if (deadOrAlive == DEAD)
			return true;
		else
			return false;
	}
	
	/** 
	 * Swim to a new location if possible.
	 * Consumes some energy.
	 */
	private void swimIfPossible() {
		// Student:Please complete this method.		

		// Consume ENERGY_TO_SWIM units of energy to swim. 
                energy = energy - ENERGY_TO_SWIM ;

		// Check if there is any energy left after consumption.
		if (energy > 0) {

			// Swim at random in one of four directions.
			// Assign a random row location for the Catfish as follows. 
			//
		        // (1) Send the "getRand" message to the "simulation" object to get a random number generator. 
			// The "simulation" object is initialized in the constructor above.
	                //
			// (2) Send the "nextInt" message to the random number generator obtained above. 
			//
			// The "nextInt" behavior returns an integer between 0(inclusive) and the integer specified as a parameter(exclusive). 
			// Thus, specifiying a value of 10 to the "nextInt" behavior will return an integer between 0 and 9.
			//
			Random randomNumberGenerator1 = simulation.getRand();
	                row = randomNumberGenerator1.nextInt(10);

			// Similarly, assign a random column location for the catfish
	                Random randomNumberGenerator2 = simulation.getRand();
	                column = randomNumberGenerator2.nextInt(10);
		}
	}

	/**
	 * Catfish lives its life. Dies if it has no energy left.
	 */
	public void liveALittle() {
		// Student:Please complete this method.

		// If there is no energy left, send a "die" message to this catfish
		if (energy <= 0) {
			die();  
		}

		// Increment the age of the Catfish by 1
                age = age + 1;
		
		// Try to swim by sending a "swimIfPossible" message
		swimIfPossible();
	}

}