dynmap-neoforge/src/main/java/org/dynmap/UpdateQueue.java
2011-05-16 20:55:19 +08:00

71 lines
2.2 KiB
Java

package org.dynmap;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.ListIterator;
public class UpdateQueue {
public Object lock = new Object();
private LinkedList<Update> updateQueue = new LinkedList<Update>();
private static final int maxUpdateAge = 120000;
public void pushUpdate(Object obj) {
synchronized (lock) {
/* Do inside lock - prevent delay between time and actual work */
long now = System.currentTimeMillis();
long deadline = now - maxUpdateAge;
ListIterator<Update> i = updateQueue.listIterator(0);
while (i.hasNext()) {
Update u = i.next();
if (u.time < deadline || u.obj == obj)
i.remove();
}
updateQueue.addLast(new Update(now, obj));
}
}
private ArrayList<Object> tmpupdates = new ArrayList<Object>();
public Object[] getUpdatedObjects(long since) {
Object[] updates;
synchronized (lock) {
long now = System.currentTimeMillis();
long deadline = now - maxUpdateAge;
tmpupdates.clear();
Iterator<Update> it = updateQueue.descendingIterator();
while (it.hasNext()) {
Update u = it.next();
if (u.time >= since) {
// Tile is new.
tmpupdates.add(u.obj);
} else if (u.time < deadline) {
// Tile is too old, removing this one (will eventually decrease).
it.remove();
break;
} else {
// Tile is old, but not old enough for removal.
break;
}
}
// Reverse output.
updates = new Object[tmpupdates.size()];
for (int i = 0; i < updates.length; i++) {
updates[i] = tmpupdates.get(updates.length-1-i);
}
}
return updates;
}
public static class Update {
public long time;
public Object obj;
public Update(long time, Object obj) {
this.time = time;
this.obj = obj;
}
}
}