evil.java

MASON代表多主体邻里或网络仿真(Multi-Agent Simulator of Neighborhoods or Networks)。它是乔治梅森大学用Java开发的离散事件多主体仿真核心库

package sim.app.virus;

import sim.util.*;
import sim.engine.*;
import java.awt.*;
import sim.portrayal.*;

public /*strictfp*/ class Evil extends Agent
    {

    protected boolean greedy = false;
    public final boolean getIsGreedy() { return greedy; }
    public final void setIsGreedy( final boolean b ) { greedy = b; }

    public Evil( String id, Double2D location ) 
        {
        super( id, location );
        try
            {
            intID = Integer.parseInt( id.substring(4) ); // "Evil"
            }
        catch( IndexOutOfBoundsException e )
            {
            System.out.println( "Exception generated: " + e );
            System.exit(1);
            }
        catch( NumberFormatException e )
            {
            System.out.println( "Exception generated: " + e );
            System.exit(1);
            }
        }

    Double2D desiredLocation = null;
    Double2D suggestedLocation = null;
    int steps = 0;

    public void step( final SimState state )
        {
        VirusInfectionDemo hb = (VirusInfectionDemo)state;

        desiredLocation = null;
        double distance2DesiredLocation = 1e30;

        Bag mysteriousObjects = hb.environment.getObjectsWithinDistance(agentLocation, 10.0 * VirusInfectionDemo.INFECTION_DISTANCE);
        if( mysteriousObjects != null )
            {
            for( int i = 0 ; i < mysteriousObjects.numObjs ; i++ )
                {
                if( mysteriousObjects.objs[i] != null &&
                    mysteriousObjects.objs[i] != this )
                    {
                    // if agent is not human, wasted time....
                    if( ! (((Agent)mysteriousObjects.objs[i]) instanceof Human ))
                        continue;
                    Human ta = (Human)(mysteriousObjects.objs[i]);
                    // if agent is already infected, wasted time....
                    if( ta.isInfected() )
                        continue;
                    if( hb.withinInfectionDistance( this, agentLocation, ta, ta.agentLocation ) )
                        ta.setInfected( true );
                    else
                        {
                        if( getIsGreedy() )
                            {
                            double tmpDist = distanceSquared( agentLocation, ta.agentLocation );
                            if( tmpDist <  distance2DesiredLocation )
                                {
                                desiredLocation = ta.agentLocation;
                                distance2DesiredLocation = tmpDist;
                                }
                            }
                        }
                    }
                }
            }

        steps--;
        if( desiredLocation == null || !getIsGreedy() )
            {
            if(  steps <= 0 )
                {
                suggestedLocation = new Double2D((state.random.nextDouble()-0.5)*((VirusInfectionDemo.XMAX-VirusInfectionDemo.XMIN)/5-VirusInfectionDemo.DIAMETER) +
                                                 //VirusInfectionDemo.XMIN
                                                 agentLocation.x 
                                                 //+VirusInfectionDemo.DIAMETER/2
                                                 ,
                                                 (state.random.nextDouble()-0.5)*((VirusInfectionDemo.YMAX-VirusInfectionDemo.YMIN)/5-VirusInfectionDemo.DIAMETER) +
                                                 agentLocation.y
                                                 //VirusInfectionDemo.YMIN
                                                 //+VirusInfectionDemo.DIAMETER/2
                    );
                steps = 100;
                }
            desiredLocation = suggestedLocation;
            }

        double dx = desiredLocation.x - agentLocation.x;
        double dy = desiredLocation.y - agentLocation.y;

            {
            double temp = 0.5 * /*Strict*/Math.sqrt(dx*dx+dy*dy);
            if( temp < 1 )
                {
                steps = 0;
                }
            else
                {
                dx /= temp;
                dy /= temp;
                }
            }

            if( ! hb.acceptablePosition( this, new Double2D(agentLocation.x + dx, agentLocation.y + dy) ) )
                {
                steps = 0;
                }
            else
                {
                agentLocation = new Double2D(agentLocation.x + dx, agentLocation.y + dy);
                hb.environment.setObjectLocation(this,agentLocation);
                }
        }

    protected Color evilColor = new Color(255,0,0);
    public final void draw(Object object, Graphics2D graphics, DrawInfo2D info)
        {
        double diamx = info.draw.width*VirusInfectionDemo.DIAMETER;
        double diamy = info.draw.height*VirusInfectionDemo.DIAMETER;

        graphics.setColor( evilColor );
        graphics.fillOval((int)(info.draw.x-diamx/2),(int)(info.draw.y-diamy/2),(int)(diamx),(int)(diamy));
        }

    public String getType() { return "Evil"; }

    }