Andreas Wundsam | cb17b23 | 2013-09-28 19:05:36 -0700 | [diff] [blame] | 1 | package org.projectfloodlight.openflow.protocol; |
| 2 | |
| 3 | import java.util.concurrent.atomic.AtomicLong; |
| 4 | |
| 5 | public class XidGenerators { |
| 6 | private static final XidGenerator GLOBAL_XID_GENERATOR = new StandardXidGenerator(); |
| 7 | |
| 8 | public static XidGenerator create() { |
| 9 | return new StandardXidGenerator(); |
| 10 | } |
| 11 | |
| 12 | public static XidGenerator global() { |
| 13 | return GLOBAL_XID_GENERATOR; |
| 14 | } |
| 15 | } |
| 16 | |
| 17 | class StandardXidGenerator implements XidGenerator { |
| 18 | |
| 19 | private final AtomicLong xidGen = new AtomicLong(); |
| 20 | long MAX_XID = 0xFFffFFffL; |
| 21 | |
| 22 | @Override |
| 23 | public long nextXid() { |
| 24 | long xid; |
| 25 | do { |
| 26 | xid = xidGen.incrementAndGet(); |
| 27 | if(xid > MAX_XID) { |
| 28 | synchronized(this) { |
| 29 | if(xidGen.get() > MAX_XID) { |
| 30 | xidGen.set(0); |
| 31 | } |
| 32 | } |
| 33 | } |
| 34 | } while(xid > MAX_XID); |
| 35 | return xid; |
| 36 | } |
| 37 | |
| 38 | } |