Level.java

package com.thecherno.cherno.engine.level;

import java.util.ArrayList;
import java.util.List;

import com.thecherno.cherno.engine.entity.Entity;
import com.thecherno.cherno.engine.graphics.Screen;
import com.thecherno.cherno.engine.interfaces.Renderable;
import com.thecherno.cherno.engine.interfaces.Updatable;

/**
 * 
 * Base {@code Level} class, override to create a more advanced {@code Level} object.
 * 
 * @author Yan Chernikov
 */
public abstract class Level implements Renderable, Updatable {

	/** The width/height of the {@code Level}. */
	protected int width, height;
	protected int xOffset, yOffset;

	/** The {@code List} containing the {@code Entity}s in the {@code Level}. */
	protected List<Entity> entities = new ArrayList<Entity>();

	/**
	 * Creates an empty {@code Level}.
	 * 
	 * @param width
	 *            The width of the {@code Level}
	 * @param height
	 *            The height of the {@code Level}
	 */
	protected Level(int width, int height) {
		this.width = width;
		this.height = height;
	}

	/**
	 * Creates a new {@code Level} object from a file.
	 * 
	 * @param fileName
	 *            The file to create the {@code Level} from.
	 */
	protected Level(String fileName) {
		load(fileName);
	}

	/**
	 * Load a level using the given file
	 * 
	 * @param fileName
	 *            The file to load the level from
	 * 
	 */
	public abstract void load(String fileName);

	/**
	 * Generate a level
	 * 
	 */
	public abstract void generate();

	/**
	 * Get the width of the {@code Level}
	 * 
	 * @return the width of the {@code Level}
	 */
	public int getWidth() {
		return width;
	}

	/**
	 * Get the height of the {@code Level}
	 * 
	 * @return the height of the {@code Level}
	 */
	public int getHeight() {
		return height;
	}

	/**
	 * Initialize an {@code Entity} and add it to the {@code Level}'s {@code Entity} list.
	 * 
	 * @return the width of the {@code Level}
	 */
	public void add(Entity e) {
		e.init(this);
		entities.add(e);
	}

	public void setOffset(int xOffset, int yOffset) {
		this.xOffset = xOffset;
		this.yOffset = yOffset;
	}

	public void render(Screen screen) {
		renderEntities(screen);
	}

	public void update() {
		updateEntities();
	}

	private void updateEntities() {
		for (int i = 0; i < entities.size(); i++) {
			entities.get(i).update();
		}
	}

	private void renderEntities(Screen screen) {
		for (int i = 0; i < entities.size(); i++) {
			entities.get(i).render(0, 0, screen);
		}
	}
}