livingbeing.java

卡耐基梅隆大学 SSD课程体系 ssd1 exesice8 答案

/*!Begin Snippet:LivingBeing*/
/*
 * Created on Jul 4, 2003
 *
 */

/**
 * Each living being lives in a location (row, column) at any given time. 
 * More than one living being can be in a location. E.g.: algae and fish.
 * Depending on the species, living beings could move. 
 * <p>
 * Each living being has some energy level. If the energy level falls below
 * the minimum needed to live, it dies. When a living being dies, it is deleted
 * from the simulation.
 * </p>
 * 
 * @author iCarnegie av
 */
public class LivingBeing {

	/**
	 * The living being is born "alive". 
	 * Then it dies, becoming a corpse. 
	 */
	protected static final String ALIVE = "alive";

	/**
	 * The living being is born "alive". 
	 * Then it dies, becoming a "dead" corpse. 
	 */
	protected static final String DEAD = "dead";

	/**
	 * Row-wise location of the living being
	 */
	protected int row;

	/**
	 * Column-wise location of the living being
	 */
	protected int column;

	/**
	 * Is the living being dead or alive?
	 */
	private String deadOrAlive;
	
	/**
	 * Amount of energy the living being has.
	 */
	private int energy;

	/**
	 * Age expressed as blocks of time lived
	 */
	private int age = 0;

	/**
	 * Name of this living being.
	 */
	private final String name;

	/**
	 * The simulation to which this living being belongs.
	 * This is needed so the living being can send a message 
	 * to simulation and ask
	 * for prey (or predator) in the neighboring locations. 
	 * Prey is food. Food is good!
	 */
	protected Simulation simulation;

	/**
	 * Minimum energy level needed to survive.
	 * The minimum could increase as the individual grows.
	 */
	protected int minEnergy;
	
	/**
	 * Maximum energy level that the living being could carry.
	 * The maximum could change as the individual grows.
	 */
	protected int maxEnergy;


	/**
	 * Create a living being at a given location with a 
	 * given energy and store the simulation to which the living being belongs.
	 * Cap row and column within lake boundary.
	 *  
	 * @param initialRow - the row location of living being
	 * @param initialColumn - the column locaiton of living being
	 * @param initialSimulation - the simulation to which this being belongs
	 * @param initialName - name of the living being
	 * @param initialMinEnergy - minimum energy to survive
	 * @param initialMaxEnergy - max energy the living being can carry 
	 */
	protected LivingBeing(
		int initialRow,
		int initialColumn,
		Simulation initialSimulation,
		String initialName,
		int initialMinEnergy,
		int initialMaxEnergy) {
			
		simulation = initialSimulation;

		deadOrAlive = ALIVE; 

		// Set the Row within bounds
		if (initialRow > simulation.getLastRow()) {
			row = simulation.getLastRow();
		} else if (initialRow < simulation.getFirstRow()) {
			row = simulation.getFirstRow();
		} else {
			row = initialRow;
		}

		// Set the Column within bounds
		if (initialColumn > simulation.getLastColumn()) {
			column = simulation.getLastColumn();
		} else if (initialColumn < simulation.getFirstColumn()) {
			column = simulation.getFirstColumn();
		} else {
			column = initialColumn;
		}

		// Set the minEnergy and maxEnergy
		minEnergy = initialMinEnergy;
		maxEnergy = initialMaxEnergy;

		energy =
			simulation.getRand().nextInt(maxEnergy - minEnergy) + minEnergy;

		age = 0;
		name = initialName;
	}

	/**
	 * Create an organism that belongs to a specified species at
	 * a specified location and add it to the specified simulation.
	 * 
	 * @param simulation - the simulation this organism belongs to
	 * @param species - the organism's species
	 * @param value - row and column values specified as String from HTML form.
	 * row value is the last two digits, 
	 * column value is given in the remaining digits.
	 */
	public static void createLivingBeing(
		Simulation sim,
		String species,
		String value) {

		int rowAndCol = Integer.parseInt(value);
		int row = rowAndCol / 100;
		int column = rowAndCol - (100 * row);

		if (species.equals("algae")) {
			sim.addLivingBeing(new AlgaeColony(row, column, sim));
		}

		if (species.equals("catfish")) {
			sim.addLivingBeing(new Catfish(row, column, sim));
		}

		if (species.equals("crocodile")) {
			sim.addLivingBeing(new Crocodile(row, column, sim));
		}
	}
	
	/**
	 * Get the row at which the living being is located 
	 * 
	 * @return - the row of the living being's location. 
	 */		
	public int getRow() {
		return row;
	}

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

	/**
	 * Get the living being's age
	 * 
	 * @return the age of the living being expressed in blocks of time
	 */
	public int getAge() {
		return age;
	}

	/**
	 * Color of the living being expressed in hex notation.
	 * For example, the "green-est" color is "#00FF00",
	 * "blue-est" is "#0000FF", the "red-est" is "#FF0000".
	 * 
	 * @return the rgb color in hex notation. preceded by a pound character '#'
	 */
	public String getColor() {
		return "#FFFFFF"; // default is white.
	}

	/**
	 * Get the name of this living being
	 * 
	 * @return the name of the living being.
	 */
	public String getName() {
		return name;
	}

	/**
	 * Get the filename that contains the image of the living being
	 * 
	 * @return the image of the living being.
	 */
	public String getImage() {
		return "/blank.gif";
	}

	/**
	 * Get the preferred display mechanism for living being
	 * 
	 * @return one of the constants IMAGE or COLOR, 
	 * depending on the display mechanism for the living being.
	 */
	public String getDisplayMechanism() {
		return Simulation.IMAGE;
	}
	
	/**
	 * Get the minimum energy needed to live.
	 * 
	 * @return the minimum energy needed for the living being to live.
	 */
	protected int getMinEnergy() {
		return minEnergy;
	}
	
	/**
	 * get the maximum energy that the living being can carry.
	 * 
	 * @return the maximum energy the living being can carry.
	 */
	protected int getMaxEnergy() {
		return maxEnergy;
	}
	

	/**
	 * Returns the species.
	 * 
	 * @return the species
	 */
	public String getSpecies() {
		return "Unknown";
	}

	/**
	 * Get the energy currently carried by the living being.
	 * 
	 * @return current energy level of the organism
	 */
	public int getEnergy() {
		return energy;
	}

	/**
	 * Sets energy level.
	 * If new energy level is less than minimum energy level, the organism dies.
	 * New energy level is capped at maximum energy level.
	 */
	protected void setEnergy(int newEnergy) {
		
		if (newEnergy < getMinEnergy()) {
			energy = newEnergy;
			die();
		} else if (newEnergy > getMaxEnergy()) {
			energy = getMaxEnergy();
		} else {
			energy = newEnergy;
		}
	}

	/**
	 * Die: Change the deadOrAlive to DEAD.
	 */
	protected void die() {
		deadOrAlive = DEAD;
	}

	/**
	 * Is the living being dead?
	 * 
	 * @return <code>true</code> if dead. <code>false</code>, otherwise.
	 */
	public boolean isDead() {
		return (deadOrAlive == DEAD);
	}

	/**
	 * The living being's age increases by one time block.
	 */
	public void liveALittle() {
		age = age + 1;
	}
}
/*!End Snippet:LivingBeing*/