catfish.java

ssd1 exercise7 以前做的 希望有帮助

import java.util.Vector;
/*
 * Created on Jul 5, 2003
 *
 */

/**
 * Catfish - simulates a catfish - can swim, eat, and consume 
 * energy in the process.
 * 
 * @author iCarnegie av
 *
 */
public class Catfish extends LivingBeing {

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

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


	/**
	 * Energy needed to swim in a block of time.
	 */
	private static final int ENERGY_TO_SWIM = 2;

	/**
	 * debugging level. 
	 */
	private static final int DEBUG = 0;
		
	/**
	 * Energy needed to look for food once.
	 */
	private static final int ENERGY_TO_LOOK_FOR_FOOD = 1;
	
	/**
	 * Energy expended to eat once.
	 */
	private static final int ENERGY_TO_EAT = 1;
	
	/**
	 * Energy gained when a full meal is eaten.
	 */
	private static final int ENERGY_IN_A_FULL_MEAL = 10;
	
	/**
	 * Lowest possible energy needed for a baby to survive. 
	 */
	private static final int BABY_MIN_ENERGY = 15;
	
	/**
	 * Maximum energy that a baby can store. 
	 */
	private static final int BABY_MAX_ENERGY = 100;

	/**
	 * For each block of time, the min energy grows by a certain amount
	 */
	private static final int MIN_ENERGY_GROWTH_INCREMENT = 5;
	
	/**
	 * For each block of time, the max energy grows by a certain amount
	 */
	private static final int MAX_ENERGY_GROWTH_INCREMENT = 10;
	
	// Concept example: final. since it is a constant 
	// Concept example: static. since only one value is needed 
	// 						irrespective of number of object instances 
	/**
	 * String constant - used to indicate the direction catfish is facing.
	 */
	private static final String RIGHT = "right";

	/**
	 * String constant - used to indicate the direction catfish is facing.
	 */
	private static final String LEFT = "left";

	/**
	 * String constant - used to indicate the direction catfish is facing.
	 */
	private static final String UP = "up";

	/**
	 * String constant - used to indicate the direction catfish is facing.
	 */
	private static final String DOWN = "down";

	/**
	 * Name of species
	 */
	private static final String SPECIES = "Catfish";

	/**
	 * Row-wise location of the catfish
	 */
	private int row;

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

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

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

	/**
	 * Name of this catfish.
	 */
	private final String name;

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

	/**
	 * Minimum energy level needed to survive.
	 * The minimum could increase as the individual grows.
	 */
	private int minEnergy;
	
	/**
	 * Maximum energy level that the catfish could carry.
	 * The maximum could change as the individual grows.
	 */
	private int maxEnergy;
	
	/**
	 * Which direction am I facing.
	 */
	private String direction; 

	/**
	 * 
	 * Number of Catfish created
	 */
	private static int nCatfishCreated = 0; 

	/**
	 * Constructor. Initialize an algae 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; 

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

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

			// Set the minEnergy and maxEnergy
			minEnergy = BABY_MIN_ENERGY;
			maxEnergy = BABY_MAX_ENERGY;

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

			age = 0;
			name = SPECIES + nCatfishCreated;
			
			direction = RIGHT; // Start by facing east.

			++nCatfishCreated;
	}
	
	/**
	 * 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 the catfish's age
	 * 
	 * @return the age of the catfish expressed in blocks of time
	 */
	public int getAge() {
		return age;
	}

	/**
	 * Color of the catfish 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 catfish
	 * 
	 * @return the name of the catfish.
	 */
	public String getName() {
		return name;
	}
	
	/**
	 * Get the minimum energy needed to live.
	 * 
	 * @return the minimum energy needed for the catfish to live.
	 */
	private int getMinEnergy() {
		return minEnergy;
	}
	
	/**
	 * get the maximum energy that the catfish can carry.
	 * 
	 * @return the maximum energy the catfish can carry.
	 */
	private int getMaxEnergy() {
		return maxEnergy;
	}
	

	/**
	 * Get the energy currently carried by the catfish.
	 * 
	 * @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.
	 */
	private 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.
	 */
	public void die() {
		deadOrAlive = DEAD;
	}

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

	/**
	 * Get the direction faced by the catfish.
	 * 
	 * @return the facing direction.
	 */
	private String getDirection() {
		return direction;
	}

	/** 
	 * Is the catfish hungry?
	 * 
	 * @return True, if hungry. False, otherwise.
	 */
	private boolean isHungry() {
		
		// Hungry, if current energy level is less than twice the 
		// amount needed for survival.
		return (getEnergy() < (2 * getMinEnergy()));
	}

	/**
	 * Move the catfish to a new row, if new row is within lake bounds.
	 * 
	 * @param newRow - the row to move to.
	 * @return the row moved to. Lake boundary limits movement.
	 */
	private int moveToRow(int newRow) {
		
		if (isDead()) {
			return -1;
		}

		// Keep the new value within lake boundary.
		if (newRow > simulation.getLastRow()) {
			newRow = simulation.getLastRow();
		} else if (newRow < simulation.getFirstRow()) {
			newRow = simulation.getFirstRow();
		}

		// I might face a new direction.
		if (newRow < row) {
			direction = UP;
		} else if (newRow > row) {
			direction = DOWN;
		}
		row = newRow;

		return row;
	}

	/**
	 * Move the catfish to a new column, if new column is within lake bounds.
	 * 
	 * @param newColumn - the column to move to.
	 * @return the column moved to. Lake boundary limits movement.
	 */
	private int moveToColumn(int newColumn) {

		if (isDead()) {
			return -1;
		}

		// System.out.println("column = " + column + ", newCOlumn = " + newColumn);
		// System.out.flush();
		// Keep the new value within lake boundary.
		if (newColumn > simulation.getLastColumn()) {
			newColumn = simulation.getLastColumn();
		} else if (newColumn < simulation.getFirstColumn()) {
			newColumn = simulation.getFirstColumn();
		}

		// I might face a new direction.
		if (newColumn < column) {
			direction = LEFT;
		} else if (newColumn > column) {
			direction = RIGHT;
		}

		column = newColumn;

		return column;
	}

	/**
	 * This individual belongs to the Catfish species.
	 *  
	 * @return The string indicating the species
	 */
	public String getSpecies() {
		return SPECIES;
	}

	/**
	 * Catfish should be displayed as an image.
	 * 
	 * @return a constant defined in {@link Simulation#IMAGE Simulation} class
	 */
	public String getDisplayMechanism() {
		return Simulation.IMAGE;
	}

	/**
	 * Get the image of the catfish
	 * 
	 * @return filename of Catfish image
	 */
	public String getImage() {
		
		if (getDirection() == RIGHT) {
			return "/Catfish-right.gif";
		}
		if (getDirection() == LEFT) {
			return "/Catfish-left.gif";
		}
		if (getDirection() == UP) {
			return "/Catfish-up.gif";
		}
		if (getDirection() == DOWN) {
			return "/Catfish-down.gif";
		}
		
		return "Catfish-right.gif";
	}

/*!Begin Snippet:lookForFoodInNeighborhood*/
	/**
	 * Look for food in the neighborhood. Consume some energy in the process.
	 * 
	 * @return a neighboring algae that is food.
	 */
	private AlgaeColony lookForFoodInNeighborhood() {
		
		int neighborIndex;
		// Looking for food consumes energy.
		setEnergy(getEnergy() - ENERGY_TO_LOOK_FOR_FOOD);

		if (isDead()) {

			return null;
		}

		Vector neighbors =
			simulation.getNeighbors(getRow(), getColumn(), 1);

		for (neighborIndex = 0;
			neighborIndex < neighbors.size();
			++neighborIndex) {
			if (neighbors.get(neighborIndex) instanceof AlgaeColony) {

				return (AlgaeColony) neighbors.get(neighborIndex);
			}
		}

		return null;
	}
/*!End Snippet:lookForFoodInNeighborhood*/
	
	/** 
	 * Swim to a new location if possible.
	 * Consumes some energy.
	 */
	private void swimIfPossible() {

		AlgaeColony food;

		if (isDead()) {

			return;
		}
		// If hungry, swim to a location where there is food.
		if (isHungry()) {

			// Naive swimming - We are not checking if a predator is in the destination.
			food = lookForFoodInNeighborhood();
			if (food != null) {
				// Consume energy to swim. 
				setEnergy(getEnergy() - ENERGY_TO_SWIM);
				if (isDead()) {

					return;
				}
				if (DEBUG > 50) {
					System.out.println(
						"moving from (row, col) = ("
							+ getRow()
							+ ", "
							+ getColumn()
							+ ") to ("
							+ food.getRow()
							+ ", "
							+ food.getColumn()
							+ ")");
				}
				moveToRow(food.getRow());
				moveToColumn(food.getColumn());

			} else {

				// Do not swim. Need to conserve energy.
			}

			return;
		} else {
			// Consume energy to swim.
			setEnergy(getEnergy() - ENERGY_TO_SWIM);
			if (isDead()) {
				return;
			}

			// Swim at random in one of four directions.
			// Naive swimming - We are not checking if a predator is in the destination.
			int direction = simulation.getRand().nextInt(4);

			// Swim up.
			if (direction == 0) {
				moveToRow(getRow() - 1);
			}

			// Swim down.
			if (direction == 1) {
				moveToRow(getRow() + 1);
			}

			// Swim left.
			if (direction == 2) {
				moveToColumn(getColumn() - 1);
			}

			// Swim right.
			if (direction == 3) {
				moveToColumn(getColumn() + 1);
			}
		}
	}

	/**
	 * Eat food if available.
	 *
	 */
	private void eatIfPossible() {
		Vector foodMaybe;
		int neighborIndex;

		if (isDead()) {
			return;
		}

		foodMaybe = simulation.getNeighbors(getRow(), getColumn(), 0);
		for (neighborIndex = 0;
			neighborIndex < foodMaybe.size();
			++neighborIndex) {

			if (foodMaybe.get(neighborIndex) instanceof AlgaeColony) {
				AlgaeColony alg = (AlgaeColony) foodMaybe.get(neighborIndex);
				int energyGained = alg.giveUpEnergy(ENERGY_IN_A_FULL_MEAL);
				// Spend ENERGY_TO_EAT, irrespective of amount gained.
				setEnergy(getEnergy() + energyGained - ENERGY_TO_EAT);

				return;
			}
		}
	}

	/**
	 * Catfish lives its life. It may lose or gain energy.
	 */
	public void liveALittle() {
		if (isDead()) {
			return;
		}
		age = age + 1;
		swimIfPossible();
		eatIfPossible();

		// As I am growing bigger, I need to increase my minEnergy 
		// and maxEnergy.
		minEnergy = getMinEnergy() + MIN_ENERGY_GROWTH_INCREMENT;
		maxEnergy = getMaxEnergy() + MAX_ENERGY_GROWTH_INCREMENT;
	}
}