src/appletbots/CarrierAgent.java

   1 /*
   2  * Copyright (c) 2002 Erik Rasmussen - All Rights Reserved
   3  */
   4 package appletbots;
   5
   6 import java.util.ArrayList;
   7 import java.util.List;
   8
   9 /**
  10  * This class represents an agent that can pick up objects in the
  11  * appletbots world.
  12  *
  13  * @author Erik Rasmussen
  14  */
  15 public abstract class CarrierAgent extends Agent
  16 {
  17         /**
  18          * The list of objects the agent is carrying
  19          */
  20         private List inventory = new ArrayList();
  21         /**
  22          * The distance the agents needs to be from an object to be able to pick
  23          * it up
  24          */
  25         private int pickUpDistance;
  26
  27         /**
  28          * Constructs an agent with the given parameters
  29          *
  30          * @param pickUpDistance  How close a CarrierAgent must be to an object to
  31          *                        pick it up
  32          * @param size            The agent's radius
  33          * @param sight           The distance the agent can see
  34          * @param maxSpeed        The maximum speed the agent can travel
  35          * @param maxAcceleration The maximum acceleration for this agent
  36          */
  37         public CarrierAgent(final int pickUpDistance, final int size, final int sight, final double maxSpeed, final double maxAcceleration)
  38         {
  39                 super(size, sight, maxSpeed, maxAcceleration);
  40                 this.pickUpDistance = pickUpDistance;
  41         }
  42
  43         /**
  44          * Picks up an object
  45          *
  46          * @param item The object to pick up
  47          */
  48         protected void pickUp(final CarriableObject item)
  49         {
  50                 inventory.add(item);
  51                 item.setCarriedBy(this);
  52         }
  53
  54         /**
  55          * Drops an object
  56          *
  57          * @param item The object to drop
  58          * @throws CollisionException Thrown if the item cannot be dropped within
  59          *                            the "pickup distance"
  60          */
  61         protected void drop(final CarriableObject item) throws CollisionException
  62         {
  63                 item.setCarriedBy(null);
  64                 try
  65                 {
  66                         world.dropItem(this, item);
  67                         inventory.remove(item);
  68                 }
  69                 catch (CollisionException e)
  70                 {
  71                         item.setCarriedBy(this);
  72                         throw e;
  73                 }
  74         }
  75
  76         /**
  77          * Returns whether or not the agent is carrying the given item
  78          *
  79          * @param item The item to check for
  80          * @return Whether or not the agent is carrying the given item
  81          */
  82         public boolean hasItem(final CarriableObject item)
  83         {
  84                 return inventory.contains(item);
  85         }
  86
  87         /**
  88          * Returns whether or not the agent is carrying any items
  89          *
  90          * @return Whether or not the agent is carrying any items
  91          */
  92         public boolean hasItems()
  93         {
  94                 return !inventory.isEmpty();
  95         }
  96
  97         /**
  98          * Returns the contents of the agent's inventory
  99          *
 100          * @return The contents of the agent's inventory
 101          */
 102         public final CarriableObject[] getInventory()
 103         {
 104                 synchronized (inventory)
 105                 {
 106                         if (inventory.isEmpty())
 107                                 return new CarriableObject[]{};
 108                         final CarriableObject[] items = new CarriableObject[inventory.size()];
 109                         for (int i = 0; i < inventory.size(); i++)
 110                                 items[i] = (CarriableObject) inventory.get(i);
 111                         return items;
 112                 }
 113         }
 114
 115         /**
 116          * Returns the distance the agents needs to be from an object to be able
 117          * to pick it up
 118          *
 119          * @return The distance the agents needs to be from an object to be able
 120          *         to pick it up
 121          */
 122         public int getPickUpDistance()
 123         {
 124                 return pickUpDistance;
 125         }
 126 }