我用 Repast 2.7 创建了疾病传播模拟器。当我尝试按开始运行时，我收到此错误：
java.lang.NullPointerException
at repast.simphony.visualization.engine.DisplayProducer.setContext(DisplayProducer.java:35)
at repast.simphony.visualization.engine.DisplayProducer.<init>(DisplayProducer.java:28)
at repast.simphony.visualization.engine.DisplayComponentControllerAction.runInitialize(DisplayComponentControllerAction.java:113)
at repast.simphony.engine.controller.DefaultController$2.visit(DefaultController.java:214)
at repast.simphony.engine.controller.DefaultController$2.visit(DefaultController.java:1)
at repast.simphony.util.collections.NaryTree.preOrderTraverals(NaryTree.java:292)
at repast.simphony.util.collections.NaryTree.preOrderTraverals(NaryTree.java:295)
at repast.simphony.util.collections.NaryTree.preOrderTraverals(NaryTree.java:295)
at repast.simphony.util.collections.NaryTree.preOrderTraversal(NaryTree.java:288)
at repast.simphony.engine.controller.DefaultController.runInitialize(DefaultController.java:212)
at repast.simphony.engine.controller.DefaultController.runInitialize(DefaultController.java:383)
at repast.simphony.ui.RSApplication.initSim(RSApplication.java:157)
at repast.simphony.ui.RSApplication.start(RSApplication.java:189)
at repast.simphony.ui.action.StartRun.actionPerformed(StartRun.java:17)
at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1967)
at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2308)
at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)
at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)
at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)
at java.desktop/java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:297)
at java.desktop/java.awt.Component.processMouseEvent(Component.java:6632)
at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)
at java.desktop/java.awt.Component.processEvent(Component.java:6397)
at java.desktop/java.awt.Container.processEvent(Container.java:2263)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5008)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4840)
at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4918)
at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4547)
at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4488)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307)
at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2772)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4840)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
我检查了所有代码 3 - 4 次，并在互联网上进行了大量研究，但我无法找出导致问题的原因。这是我的代码：
我所有的项目： https ://drive.google.com/drive/folders/1jFfUmBZEznCTASUJ0D6QoPv-p62yUbin
我的课在这里：
健康代理类：
import java.util.List;
import repast.simphony.engine.environment.RunEnvironment;
import repast.simphony.engine.schedule.ScheduledMethod;
import repast.simphony.parameter.Parameters;
import repast.simphony.query.space.grid.GridCell;
import repast.simphony.query.space.grid.GridCellNgh;
import repast.simphony.random.RandomHelper;
import repast.simphony.space.SpatialMath;
import repast.simphony.space.continuous.ContinuousSpace;
import repast.simphony.space.continuous.NdPoint;
import repast.simphony.space.grid.Grid;
import repast.simphony.space.grid.GridPoint;
import repast.simphony.util.SimUtilities;
public class Healthy {
private ContinuousSpace<Object> space;
private Grid<Object> grid;
Parameters params = RunEnvironment.getInstance().getParameters();
double chance_to_infect ;
private double prob_to_social_isolate = 0.65 ;
boolean social_isolate ;
public Healthy(ContinuousSpace<Object> space, Grid<Object> grid) {
this.space = space;
this.grid = grid;
this.chance_to_infect = 0.785 ;
this.social_isolate = true ;
if(Math.random() <= prob_to_social_isolate) {
this.social_isolate = false;
}
}
@ScheduledMethod(start = 1, interval = 1)
public void step() {
//if(Math.random() <= prob_to_social_isolation)
if(this.social_isolate) {
return;
}
// get the grid location of this Human
GridPoint pt = grid.getLocation(this);
// use the GridCellNg class to create GridCell for
// the surronding neighborgood.
GridCellNgh<Object> nghCreator = new GridCellNgh<Object> ( grid, pt, Object.class, 1, 1);
List<GridCell<Object>> gridCells = nghCreator.getNeighborhood(true);
SimUtilities.shuffle(gridCells, RandomHelper.getUniform());
GridCell<Object> cell = gridCells.get(0);
GridPoint point_to_move = cell.getPoint();
}
public void moveTowards (GridPoint pt) {
// only move if we are not already in this grid location
if(!pt.equals(grid.getLocation(this))) {
NdPoint myPoint = space.getLocation(this);
NdPoint otherPoint = new NdPoint(pt.getX(), pt.getY());
double angle = SpatialMath.calcAngleFor2DMovement(space, myPoint,
otherPoint);
space.moveByVector( this, 2, angle, 0);
myPoint = space.getLocation(this);
grid.moveTo(this, (int) myPoint.getX(), (int) myPoint.getY());
}
}
}
死代理类：
import repast.simphony.space.continuous.ContinuousSpace;
import repast.simphony.space.grid.Grid;
public class Dead {
private ContinuousSpace<Object> space;
private Grid<Object> grid;
public Dead (ContinuousSpace<Object> space, Grid<Object> grid) {
this.space = space;
this.grid = grid;
}
}
住院代理类：
import java.util.ArrayList;
import java.util.List;
import repast.simphony.context.Context;
import repast.simphony.engine.schedule.ScheduledMethod;
import repast.simphony.query.space.grid.GridCell;
import repast.simphony.query.space.grid.GridCellNgh;
import repast.simphony.random.RandomHelper;
import repast.simphony.space.SpatialMath;
import repast.simphony.space.continuous.ContinuousSpace;
import repast.simphony.space.continuous.NdPoint;
import repast.simphony.space.graph.Network;
import repast.simphony.space.grid.Grid;
import repast.simphony.space.grid.GridPoint;
import repast.simphony.util.ContextUtils;
import repast.simphony.util.SimUtilities;
public class Hospitalized {
private ContinuousSpace<Object> space;
private Grid<Object> grid;
double prob_recover ;
public Hospitalized (ContinuousSpace<Object> space, Grid<Object> grid) {
this.space = space;
this.grid = grid;
this.prob_recover = 0.8 ;
}
@ScheduledMethod(start = 1, interval = 1)
public void step() {
//if(Math.random() <= prob_to_social_isolation)
// get the grid location of this Human
GridPoint pt = grid.getLocation(this);
// use the GridCellNg class to create GridCell for
// the surronding neighborgood.
GridCellNgh<Object> nghCreator = new GridCellNgh<Object> ( grid, pt, Object.class, 1, 1);
List<GridCell<Object>> gridCells = nghCreator.getNeighborhood(true);
SimUtilities.shuffle(gridCells, RandomHelper.getUniform());
GridCell<Object> cell = gridCells.get(0);
GridPoint point_to_move = cell.getPoint();
}
public void moveTowards (GridPoint pt) {
// only move if we are not already in this grid location
if(!pt.equals(grid.getLocation(this))) {
NdPoint myPoint = space.getLocation(this);
NdPoint otherPoint = new NdPoint(pt.getX(), pt.getY());
double angle = SpatialMath.calcAngleFor2DMovement(space, myPoint,
otherPoint);
space.moveByVector( this, 2, angle, 0);
myPoint = space.getLocation(this);
grid.moveTo(this, (int) myPoint.getX(), (int) myPoint.getY());
}
}
public void dead() {
GridPoint pt = grid.getLocation(this);
List<Object> hospitalized = new ArrayList<Object>();
//Get all infected at the new location
for (Object obj : grid.getObjectsAt(pt.getX(), pt.getY())) {
if(obj instanceof Hospitalized){
hospitalized.add(obj);
}
}
if(hospitalized.size() > 0) {
for(Object obj : hospitalized ) {
double random = Math.random();
if(random >= ((Hospitalized) obj).prob_recover){
NdPoint spacePt = space.getLocation(obj);
Context<Object> context = ContextUtils.getContext(obj);
context.remove(obj);
Dead dead = new Dead(space, grid);
context.add(dead);
space.moveTo(dead, spacePt.getX(), spacePt.getY());
grid.moveTo(dead, pt.getX(), pt.getY());
Network<Object> net = (Network<Object>) context.getProjection("infection network");
net.addEdge(this, dead);
}
}
}
}
}
受感染的代理类：
import java.util.ArrayList;
import java.util.List;
import repast.simphony.context.Context;
import repast.simphony.engine.schedule.ScheduledMethod;
import repast.simphony.query.space.grid.GridCell;
import repast.simphony.query.space.grid.GridCellNgh;
import repast.simphony.random.RandomHelper;
import repast.simphony.space.SpatialMath;
import repast.simphony.space.continuous.ContinuousSpace;
import repast.simphony.space.continuous.NdPoint;
import repast.simphony.space.graph.Network;
import repast.simphony.space.grid.Grid;
import repast.simphony.space.grid.GridPoint;
import repast.simphony.util.ContextUtils;
import repast.simphony.util.SimUtilities;
public class Infected {
private ContinuousSpace<Object> space;
private Grid<Object> grid;
private int days_infected ;
double prob_to_go_to_hospital ;
double prob_recover_without_hospital ;
private boolean hospitalized;
public Hospital hospital;
public Infected (ContinuousSpace<Object> space, Grid<Object> grid) {
this.space = space;
this.grid = grid;
this.days_infected = ((int) Math.random()*14);
this.prob_to_go_to_hospital = 0.875;
this.prob_recover_without_hospital = 0.2 ;
this.hospitalized = false;
this.hospital = null;
}
@ScheduledMethod(start = 1, interval = 1)
public void step() {
// get the grid location of this Human
GridPoint pt = grid.getLocation(this);
// use the GridCellNg class to create GridCell for
// the surronding neighborgood.
GridCellNgh<Object> nghCreator = new GridCellNgh<Object> ( grid, pt, Object.class, 1, 1);
List<GridCell<Object>> gridCells = nghCreator.getNeighborhood(true);
SimUtilities.shuffle(gridCells, RandomHelper.getUniform());
GridCell<Object> cell = gridCells.get(0);
GridPoint point_to_move = cell.getPoint();
}
public void moveTowards (GridPoint pt) {
// only move if we are not already in this grid location
if(!pt.equals(grid.getLocation(this))) {
NdPoint myPoint = space.getLocation(this);
NdPoint otherPoint = new NdPoint(pt.getX(), pt.getY());
double angle = SpatialMath.calcAngleFor2DMovement(space, myPoint,
otherPoint);
space.moveByVector( this, 2, angle, 0);
myPoint = space.getLocation(this);
grid.moveTo(this, (int) myPoint.getX(), (int) myPoint.getY());
}
}
public void infect(){
GridPoint pt = grid.getLocation(this);
List<Object> healthy = new ArrayList<Object>();
//Get all healthys at the new location
for (Object obj : grid.getObjectsAt(pt.getX(), pt.getY())) {
if(obj instanceof Healthy){
healthy.add(obj);
}
}
//infect any random healthy
if(healthy.size() > 0) {
for(Object obj : healthy) {
double random = Math.random();
if(random <= ((Healthy) obj).chance_to_infect && !((Healthy) obj).social_isolate ){
NdPoint spacePt = space.getLocation(obj);
Context<Object> context = ContextUtils.getContext(obj);
context.remove(obj);
Infected infected = new Infected(space, grid);
context.add(infected);
space.moveTo(infected, spacePt.getX(), spacePt.getY());
grid.moveTo(infected, pt.getX(), pt.getY());
Network<Object> net = (Network<Object>) context.getProjection("infection network");
net.addEdge(this, infected);
}
}
}
}
public void hospitalized() {
GridPoint pt = grid.getLocation(this);
List<Object> infected = new ArrayList<Object>();
//Get all infected at the new location
for (Object obj : grid.getObjectsAt(pt.getX(), pt.getY())) {
if(obj instanceof Infected){
infected.add(obj);
}
}
if(infected.size() > 0) {
for(Object obj : infected ) {
if(((Infected) obj).hospitalized == true ){
NdPoint spacePt = space.getLocation(obj);
Context<Object> context = ContextUtils.getContext(obj);
context.remove(obj);
Hospitalized hospitalized = new Hospitalized(space, grid);
context.add(hospitalized);
space.moveTo(hospitalized, spacePt.getX(), spacePt.getY());
grid.moveTo(hospitalized, pt.getX(), pt.getY());
Network<Object> net = (Network<Object>) context.getProjection("infection network");
net.addEdge(this, hospitalized);
}
}
}
}
public void dead () {
GridPoint pt = grid.getLocation(this);
List<Object> infected = new ArrayList<Object>();
//Get all infected at the new location
for (Object obj : grid.getObjectsAt(pt.getX(), pt.getY())) {
if(obj instanceof Infected){
infected.add(obj);
}
}
if(infected.size() > 0) {
for(Object obj : infected ) {
double random = Math.random();
if(((Infected) obj).hospitalized == false && days_infected > 15 &&
random >= ((Infected) obj).prob_recover_without_hospital){
NdPoint spacePt = space.getLocation(obj);
Context<Object> context = ContextUtils.getContext(obj);
context.remove(obj);
Dead dead = new Dead(space, grid);
context.add(dead);
space.moveTo(dead, spacePt.getX(), spacePt.getY());
grid.moveTo(dead, pt.getX(), pt.getY());
Network<Object> net = (Network<Object>) context.getProjection("infection network");
net.addEdge(this, dead);
}
}
}
}
public Hospital getNearestHospital() {
double minDistSq = Double.POSITIVE_INFINITY ;
Hospital minAgent = null ;
NdPoint myLocation ;
Context context = ContextUtils.getContext(this);
for(Object agent: context) {
if(agent instanceof Hospital) {
Hospital thishospital = (Hospital) agent;
if(thishospital.current_capacity > 0) {
NdPoint currloc = space.getLocation(this);
NdPoint loc = space.getLocation(agent);
double distSq = ((currloc.getX() - loc.getX())*(currloc.getX() - loc.getX()))+((currloc.getY() - loc.getY())*(currloc.getY() - loc.getY()));
if (distSq < minDistSq) {
minDistSq = distSq;
minAgent = (Hospital) agent;
}
}
}
}
minAgent.current_capacity --;
return minAgent;
}
private void go_to_hospital() {
if(Math.random() < prob_to_go_to_hospital) {
//Write code to get nearest hospital
//send agent there
Hospital nearest_hospital = getNearestHospital();
if(nearest_hospital == null) {
return;
}
NdPoint target_location = space.getLocation(nearest_hospital);
space.moveTo(this, (double)target_location.getX(), (double)target_location.getY());
grid.moveTo(this, (int) target_location.getX(), (int) target_location.getY());
this.hospital = nearest_hospital ;
hospitalized = true ;
}
}
}
恢复的代理类：
import java.util.List;
import repast.simphony.engine.environment.RunEnvironment;
import repast.simphony.engine.schedule.ScheduledMethod;
import repast.simphony.parameter.Parameters;
import repast.simphony.query.space.grid.GridCell;
import repast.simphony.query.space.grid.GridCellNgh;
import repast.simphony.random.RandomHelper;
import repast.simphony.space.SpatialMath;
import repast.simphony.space.continuous.ContinuousSpace;
import repast.simphony.space.continuous.NdPoint;
import repast.simphony.space.grid.Grid;
import repast.simphony.space.grid.GridPoint;
import repast.simphony.util.SimUtilities;
public class Recovered{
private ContinuousSpace<Object> space;
private Grid<Object> grid;
public Recovered(ContinuousSpace<Object> space, Grid<Object> grid) {
this.space = space;
this.grid = grid;
}
@ScheduledMethod(start = 1, interval = 1)
public void step() {
GridPoint pt = grid.getLocation(this);
GridCellNgh<Object> nghCreator = new GridCellNgh<Object> ( grid, pt, Object.class, 1, 1);
List<GridCell<Object>> gridCells = nghCreator.getNeighborhood(true);
SimUtilities.shuffle(gridCells, RandomHelper.getUniform());
GridCell<Object> cell = gridCells.get(0);
GridPoint point_to_move = cell.getPoint();
}
public void moveTowards (GridPoint pt) {
// only move if we are not already in this grid location
if(!pt.equals(grid.getLocation(this))) {
NdPoint myPoint = space.getLocation(this);
NdPoint otherPoint = new NdPoint(pt.getX(), pt.getY());
double angle = SpatialMath.calcAngleFor2DMovement(space, myPoint,
otherPoint);
space.moveByVector( this, 2, angle, 0);
myPoint = space.getLocation(this);
grid.moveTo(this, (int) myPoint.getX(), (int) myPoint.getY());
}
}
医院代理类：
import repast.simphony.engine.environment.RunEnvironment;
import repast.simphony.parameter.Parameters;
import repast.simphony.space.continuous.ContinuousSpace;
import repast.simphony.space.grid.Grid;
public class Hospital {
Parameters params = RunEnvironment.getInstance().getParameters();
private int number_of_rooms = 10;
public int current_capacity;
private ContinuousSpace<Object> space;
private Grid<Object> grid;
public Hospital (ContinuousSpace<Object> space, Grid<Object> grid) {
this.space = space;
this.grid = grid;
this.current_capacity = number_of_rooms;
}
}
生成器类：
import repast.simphony.context.Context;
import repast.simphony.context.DefaultContext;
import repast.simphony.context.space.continuous.ContinuousSpaceFactory;
import repast.simphony.context.space.continuous.ContinuousSpaceFactoryFinder;
import repast.simphony.context.space.graph.NetworkBuilder;
import repast.simphony.context.space.grid.GridFactory;
import repast.simphony.context.space.grid.GridFactoryFinder;
import repast.simphony.dataLoader.ContextBuilder;
import repast.simphony.engine.environment.RunEnvironment;
import repast.simphony.parameter.Parameters;
import repast.simphony.random.RandomHelper;
import repast.simphony.space.continuous.ContinuousSpace;
import repast.simphony.space.continuous.NdPoint;
import repast.simphony.space.continuous.RandomCartesianAdder;
import repast.simphony.space.grid.Grid;
import repast.simphony.space.grid.GridBuilderParameters;
import repast.simphony.space.grid.SimpleGridAdder;
import repast.simphony.space.grid.WrapAroundBorders;
public class diseaseSpreadSimulatorBuilder implements ContextBuilder<Object> {
@Override
public Context<Object> build(Context<Object> context) {
context.setId("diseaseSpreadSimulator");
NetworkBuilder <Object> netBuilder = new NetworkBuilder<Object>("infection network", context,true);
netBuilder.buildNetwork();
ContinuousSpaceFactory spaceFactory = ContinuousSpaceFactoryFinder.createContinuousSpaceFactory(null);
ContinuousSpace<Object> space = spaceFactory.createContinuousSpace("space", context, new RandomCartesianAdder<Object>(),
new repast.simphony.space.continuous.WrapAroundBorders(), 50 , 50);
GridFactory gridFactory = GridFactoryFinder.createGridFactory(null);
Grid<Object> grid = gridFactory.createGrid("grid", context,
new GridBuilderParameters<Object>(new WrapAroundBorders(),new SimpleGridAdder<Object>(), true, 50, 50));
Parameters params = RunEnvironment.getInstance().getParameters();
int infectedCount = (Integer)params.getValue("infected_count");
for(int i = 0; i < infectedCount; i++) {
context.add(new Infected(space, grid));
}
int healthyCount = (Integer)params.getValue("healthy_count");
for(int i=0; i < healthyCount; i++ ) {
context.add(new Healthy(space, grid));
}
int hospitalCount = (Integer)params.getValue("hospital_count");
for(int i=0; i < hospitalCount; i++ ) {
context.add(new Hospital(space, grid));
}
for (Object obj : context) {
NdPoint pt = space.getLocation(obj);
grid.moveTo(obj, (int) pt.getX(), (int) pt.getY());
}
if (RunEnvironment.getInstance().isBatch()) {
RunEnvironment.getInstance().endAt(20);
}
return context;
}
}