Github user fpj commented on a diff in the pull request:
https://github.com/apache/zookeeper/pull/150#discussion_r97437693
--- Diff: src/java/main/org/apache/zookeeper/client/StaticHostProvider.java
---
@@ -87,15 +86,69 @@ public StaticHostProvider(Collection<InetSocketAddress>
serverAddresses)
Collections.shuffle(this.serverAddresses);
}
+ /**
+ * In Java 7, we have a method getHostString, but earlier versions do
not support it.
+ * This method is to provide a replacement for
InetSocketAddress.getHostString().
+ *
+ * It evaluates to a hostname if one is available and otherwise it
returns the
+ * string representation of the IP address.
+ *
+ * @param addr
+ * @return Hostname string of address parameter
+ */
+ private String getHostString(InetSocketAddress addr) {
+ String hostString;
+ InetAddress ia = addr.getAddress();
+
+ if (ia != null) {
+ // If the string starts with '/', then it has no hostname
+ // and we want to avoid the reverse lookup, so we return
+ // the string representation of the address.
+ if (ia.toString().startsWith("/")) {
+ hostString = ia.getHostAddress();
+ } else {
+ hostString = addr.getHostName();
+ }
+ } else {
+ // According to the Java 6 documentation, if the hostname is
+ // unresolved, then the string before the colon is the
hostname.
+ String addrString = addr.toString();
+ hostString = addrString.substring(0,
addrString.lastIndexOf(':'));
+ }
+
+ return hostString;
+ }
+
public int size() {
return serverAddresses.size();
}
public InetSocketAddress next(long spinDelay) {
- ++currentIndex;
- if (currentIndex == serverAddresses.size()) {
- currentIndex = 0;
+ // Handle possible connection error by re-resolving hostname if
possible
+ if (!connectedSinceNext) {
+ InetSocketAddress curAddr = serverAddresses.get(currentIndex);
+ if
(!curAddr.getHostString().equals(curAddr.getAddress().getHostAddress())) {
+ try {
+ int thePort = curAddr.getPort();
+ InetAddress resolvedAddresses[] =
InetAddress.getAllByName(getHostString(curAddr));
+ if (resolvedAddresses.length == 1) {
+ serverAddresses.set(currentIndex, new
InetSocketAddress(resolvedAddresses[0], thePort));
+ } else {
+ serverAddresses.remove(currentIndex);
+ for (InetAddress resolvedAddress :
resolvedAddresses) {
+ InetSocketAddress newAddr = new
InetSocketAddress(resolvedAddress, thePort);
+ if (!serverAddresses.contains(newAddr)) {
+ serverAddresses.add(newAddr);
+ }
+ }
--- End diff --
We shuffle initially to avoid having all clients connecting to the same
server in the case they are all given the same connect string. If the array of
addresses has already been shuffled (in the constructor), then the order
followed in this method will be the shuffled one. I don't see a strong reason
for re-shuffling, as we are not bringing it back to the original order by
resolving again.
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