A RePast Tutorial by John T. Murphy, University of Arizona & Arizona State University (contact)

Displaying Agents

To display the agents we need to do the following things:

We need to create an Object2DDisplay object, which is similar to the Value2DDisplay object in that it links a grid and something to be displayed on that grid. In this case, however, what is to be displayed is not a value but a list of objects. We then add the agent list as that Object2DDisplay object's list of objects, and add it to the display surface.
We need to make the agents able to be drawn by implementing the 'drawable' interface. The 'drawable' interface requires that the agents:

Have 'get' methods for their x and y positions, named 'getX()' and 'getY()' and returning int values.
Have a 'draw' method that takes a 'SimGraphics' object as an argument and provides a set of instructions for how the object should be drawn.

One important note is that when the objects are added to the display surface, order matters- things that are added first are drawn first, and hence we want to add the money space first so that it is drawn in the 'background,' and the agents second so that they appear in the 'foreground.'

Pay careful attention in the code below to the scraps of code that have been added at the tops of files, especially the new 'implements' keyword in the CarryDropAgent file.

CarryDropModel

// CarryDropModel
package demo;

import java.awt.Color;
import java.util.ArrayList;

import uchicago.src.sim.engine.Schedule;
import uchicago.src.sim.engine.SimInit;
import uchicago.src.sim.engine.SimModelImpl;
import uchicago.src.sim.gui.DisplaySurface;
import uchicago.src.sim.gui.ColorMap;
import uchicago.src.sim.gui.Object2DDisplay;
import uchicago.src.sim.gui.Value2DDisplay;

public class CarryDropModel extends SimModelImpl {
  // Default Values
  private static final int NUMAGENTS = 100;
  private static final int WORLDXSIZE = 40;
  private static final int WORLDYSIZE = 40;
  private static final int TOTALMONEY = 1000;
  private static final int AGENT_MIN_LIFESPAN = 30;
  private static final int AGENT_MAX_LIFESPAN = 50;

  private int numAgents = NUMAGENTS;
  private int worldXSize = WORLDXSIZE;
  private int worldYSize = WORLDYSIZE;
  private int money = TOTALMONEY;
  private int agentMinLifespan = AGENT_MIN_LIFESPAN;
  private int agentMaxLifespan = AGENT_MAX_LIFESPAN;

  private Schedule schedule;

  private CarryDropSpace cdSpace;

  private ArrayList agentList;

  private DisplaySurface displaySurf;

  public String getName(){
    return "Carry And Drop";
  }

  public void setup(){
    System.out.println("Running setup");
    cdSpace = null;
    agentList = new ArrayList();

    if (displaySurf != null){
      displaySurf.dispose();
    }
    displaySurf = null;

    displaySurf = new DisplaySurface(this, "Carry Drop Model Window 1");

    registerDisplaySurface("Carry Drop Model Window 1", displaySurf);
  }

  public void begin(){
    buildModel();
    buildSchedule();
    buildDisplay();

    displaySurf.display();
  }

  public void buildModel(){
    System.out.println("Running BuildModel");
    cdSpace = new CarryDropSpace(worldXSize, worldYSize);
    cdSpace.spreadMoney(money);

    for(int i = 0; i < numAgents; i++){
      addNewAgent();
    }
    for(int i = 0; i < agentList.size(); i++){
      CarryDropAgent cda = (CarryDropAgent)agentList.get(i);
      cda.report();
    }
  }

  public void buildSchedule(){
    System.out.println("Running BuildSchedule");
  }

  public void buildDisplay(){
    System.out.println("Running BuildDisplay");

    ColorMap map = new ColorMap();

    for(int i = 1; i<16; i++){
      map.mapColor(i, new Color((int)(i * 8 + 127), 0, 0));
    }
    map.mapColor(0, Color.white);

    Value2DDisplay displayMoney =
        new Value2DDisplay(cdSpace.getCurrentMoneySpace(), map);

    Object2DDisplay displayAgents = new Object2DDisplay(cdSpace.getCurrentAgentSpace());
    displayAgents.setObjectList(agentList);

    displaySurf.addDisplayable(displayMoney, "Money");
    displaySurf.addDisplayable(displayAgents, "Agents");

  }

  private void addNewAgent(){
    CarryDropAgent a = new CarryDropAgent(agentMinLifespan, agentMaxLifespan);
    agentList.add(a);
    cdSpace.addAgent(a);
  }
  public Schedule getSchedule(){
    return schedule;
  }

  public String[] getInitParam(){
    String[] initParams = { "NumAgents", "WorldXSize", "WorldYSize", "Money", "AgentMinLifespan", "AgentMaxLifespan"};
    return initParams;
  }

  public int getNumAgents(){
    return numAgents;
  }

  public void setNumAgents(int na){
    numAgents = na;
  }

  public int getWorldXSize(){
    return worldXSize;
  }

  public void setWorldXSize(int wxs){
    worldXSize = wxs;
  }

  public int getWorldYSize(){
    return worldYSize;
  }

  public void setWorldYSize(int wys){
    worldYSize = wys;
  }

  public int getMoney() {
    return money;
  }

  public void setMoney(int i) {
    money = i;
  }

  public int getAgentMaxLifespan() {
    return agentMaxLifespan;
  }

  public int getAgentMinLifespan() {
    return agentMinLifespan;
  }

  public void setAgentMaxLifespan(int i) {
    agentMaxLifespan = i;
  }

  public void setAgentMinLifespan(int i) {
    agentMinLifespan = i;
  }

  public static void main(String[] args) {
    SimInit init = new SimInit();
    CarryDropModel model = new CarryDropModel();
    init.loadModel(model, "", false);
  }

}

CarryDropAgent

// CarryDropAgent
package demo;

import java.awt.Color;

import uchicago.src.sim.gui.Drawable;
import uchicago.src.sim.gui.SimGraphics;

public class CarryDropAgent implements Drawable{
  private int x;
  private int y;
  private int money;
  private int stepsToLive;
  private static int IDNumber = 0;
  private int ID;

  public CarryDropAgent(int minLifespan, int maxLifespan){
    x = -1;
    y = -1;
    money = 0;
    stepsToLive =
        (int)((Math.random() * (maxLifespan - minLifespan)) + minLifespan);
    IDNumber++;
    ID = IDNumber;
  }

  public void setXY(int newX, int newY){
    x = newX;
    y = newY;
  }

  public String getID(){
    return "A-" + ID;
  }

  public int getMoney(){
    return money;
  }

  public int getStepsToLive(){
    return stepsToLive;
  }

  public void report(){
    System.out.println(getID() +
                       " at " +
                       x + ", " + y +
                       " has " +
                       getMoney() + " dollars" +
                       " and " +
                       getStepsToLive() + " steps to live.");
  }

  public int getX(){
    return x;
  }

  public int getY(){
    return y;
  }

  public void draw(SimGraphics G){
    G.drawFastRoundRect(Color.blue);
  }
}

CarryDropSpace

// CarryDropSpace
package demo;

import uchicago.src.sim.space.Object2DGrid;

public class CarryDropSpace {
private Object2DGrid moneySpace;
private Object2DGrid agentSpace;

  public CarryDropSpace(int xSize, int ySize){
    moneySpace = new Object2DGrid(xSize, ySize);
    agentSpace = new Object2DGrid(xSize, ySize);

    for(int i = 0; i < xSize; i++){
      for(int j = 0; j < ySize; j++){
        moneySpace.putObjectAt(i,j,new Integer(0));
      }
    }
  }

  public void spreadMoney(int money){
    // Randomly place money in moneySpace
    for(int i = 0; i < money; i++){

      // Choose coordinates
      int x = (int)(Math.random()*(moneySpace.getSizeX()));
      int y = (int)(Math.random()*(moneySpace.getSizeY()));

      // Get the value of the object at those coordinates
      int currentValue = getMoneyAt(x, y);
      // Replace the Integer object with another one with the new value
      moneySpace.putObjectAt(x,y,new Integer(currentValue + 1));
    }
  }

  public int getMoneyAt(int x, int y){
    int i;
    if(moneySpace.getObjectAt(x,y)!= null){
      i = ((Integer)moneySpace.getObjectAt(x,y)).intValue();
    }
    else{
      i = 0;
    }
    return i;
  }

  public Object2DGrid getCurrentMoneySpace(){
    return moneySpace;
  }

  public Object2DGrid getCurrentAgentSpace(){
    return agentSpace;
  }

  public boolean isCellOccupied(int x, int y){
    boolean retVal = false;
    if(agentSpace.getObjectAt(x, y)!=null) retVal = true;
    return retVal;
  }

  public boolean addAgent(CarryDropAgent agent){
    boolean retVal = false;
    int count = 0;
    int countLimit = 10 * agentSpace.getSizeX() * agentSpace.getSizeY();

    while((retVal==false) && (count < countLimit)){
      int x = (int)(Math.random()*(agentSpace.getSizeX()));
      int y = (int)(Math.random()*(agentSpace.getSizeY()));
      if(isCellOccupied(x,y) == false){
        agentSpace.putObjectAt(x,y,agent);
        agent.setXY(x,y);
        retVal = true;
      }
      count++;
    }

    return retVal;
  }

}

Previous: Reporting

Next: Adding a Schedule and Some Action

Go to Table of Contents

A RePast Tutorial by John T. Murphy, University of Arizona & Arizona State University (contact)