add some random bytes to baseId. Patch from Gary Tully (GERONIMO-4393)
git-svn-id: https://svn.apache.org/repos/asf/geronimo/components/txmanager/trunk@740839 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/geronimo-transaction/src/main/java/org/apache/geronimo/transaction/manager/XidFactoryImpl.java b/geronimo-transaction/src/main/java/org/apache/geronimo/transaction/manager/XidFactoryImpl.java
index 6412438..afc9608 100644
--- a/geronimo-transaction/src/main/java/org/apache/geronimo/transaction/manager/XidFactoryImpl.java
+++ b/geronimo-transaction/src/main/java/org/apache/geronimo/transaction/manager/XidFactoryImpl.java
@@ -17,6 +17,7 @@
package org.apache.geronimo.transaction.manager;
+import java.util.Random;
import javax.transaction.xa.Xid;
import java.net.InetAddress;
import java.net.UnknownHostException;
@@ -26,6 +27,7 @@
* The Xid is constructed of three parts:
* <ol><li>8 byte count (LSB first)</li>
* <li>4 byte system id</li>
+ * <li>2 byte entropy</li>
* <li>4 or 16 byte IP address of host</li>
* <ol>
* @version $Rev$ $Date$
@@ -51,7 +53,13 @@
baseId[9] = (byte) (uid >>> 8);
baseId[10] = (byte) (uid >>> 16);
baseId[11] = (byte) (uid >>> 24);
- System.arraycopy(hostid, 0, baseId, 12, hostid.length);
+
+ byte[] entropy = new byte[2];
+ new Random().nextBytes(entropy);
+ baseId[12] = entropy[0];
+ baseId[13] = entropy[1];
+
+ System.arraycopy(hostid, 0, baseId, 14, hostid.length);
}
public Xid createXid() {
