我想让一架飞机从一个机场飞到另一个机场。飞机起飞时，飞机场被封锁5秒钟。（如果另一架飞机要降落或起飞-必须等待）。如果一架飞机到达目的地，它会降落（如果飞机场没有被另一架飞机挡住），然后进入一个随机的飞机场然后飞到那里，依此类推....我在评论中有疑问-如何使线程等待？我的代码还有什么问题呢？这是我的课萨莫洛特又名飞机：
public class Samolot extends Thread{
int id;
double paliwo;
Lotnisko source; //Lotnisko aka airfield
Lotnisko dest;
double xPosition;
double yPosition;
double xTarget;
double yTarget;
public Samolot(Lotnisko source, Lotnisko dest) {
this.source = source;
this.dest = dest;
paliwo = 100;
}
public void run(){
while(true){
tryStart();
}
}
public void tryStart(){
if(source.pas == true){ // if true the airfield is not blocked and we can go
source.timer(); // its a method in class Lotnisko, makes pas = false for 8sec
lecimy(source, dest);
}
else if(source.pas == false){
// how to make a thread wait ?
}
}
public void tryLadowanie(){
if(dest.pas == true){
dest.timer();
source = dest;
dest = Rand(source);
tryStart();
}
else if(dest.pas == false){
//how to make a thread wait ?
}
}
public void lecimy(Lotnisko source, Lotnisko dest){
xPosition = source.coords.getX();
yPosition = source.coords.getY();
xTarget = dest.coords.getX();
yTarget = dest.coords.getY();
while( (xPosition != xTarget) && (yPosition != yTarget) ){
update();
try{
sleep(100);// ok
}
catch (InterruptedException e) {
System.out.println("Error");
}
}
tryLadowanie();
}
public void update() {
paliwo -= 0.05;
double dx = xTarget - xPosition;
double dy = yTarget - yPosition;
double length = sqrt(dx*dx+dy*dy);
dx /= length;
dy /= length;
if (Math.abs(dest.coords.getX() - source.coords.getX()) < 1)
dx = 0;
if (Math.abs(dest.coords.getY() - source.coords.getY()) < 1)
dy = 0;
xPosition += dx;
yPosition += dy;
}
public Point getPositions() {
Point curPos = new Point((int)xPosition, (int)yPosition);
return curPos;
}
好的，所以您的飞机是一条线，飞机场是共享资源。因此，为了使飞机（线程）等待，您需要在共享资源（机场）上进行同步。您可能会做这样的事情。
为了起飞
public void tryStart() {
synchronized(source) { // try to obtain source lock
try {
Thread.sleep(5000); // lock it for 5 seconds.
}
catch(Exception ignore) {
// You'll need to decide what to do if something interrupts the thread while it's "sleeping" (ie. locked) on the source airfield. Normally, this should not happen.
}
}
// After 5 seconds, releases lock on airfield "source" and Plane starts flying
}
对于着陆
public void tryLadowanie() {
synchronized(dest) { // try to obtain dest lock
// successfully obtained lock.
// perform your landing
}
// plane landed and releases "dest" resource for other planes (ie. threads)
}
有关飞机飞行的更完整图片。
public void run(){
while(true){
tryStart(); // take off from source
lecimy(); // fly the plane. Method will only return when plane reaches destination.
tryLadowanie(); // land the plane
source = dest;
dest = Rand(source); // returns a new destination but can't be the same as source
}
}
public void tryStart(){
synchronized(source) {
try {
Thread.sleep(5000);
}
catch(Exception ignore) { }
}
}
public void tryLadowanie(){
synchronized(dest) {
// land the plane
}
}
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