Revision: 10026
Author: [email protected]
Date: Tue Apr 19 08:27:36 2011
Log: Proposition: Use ConcurrentHashMap to avoid locking when using the
clientOracleCache.
Review at http://gwt-code-reviews.appspot.com/1425803
http://code.google.com/p/google-web-toolkit/source/detail?r=10026
Modified:
/trunk/user/src/com/google/gwt/rpc/server/RpcServlet.java
=======================================
--- /trunk/user/src/com/google/gwt/rpc/server/RpcServlet.java Thu Dec 16
11:33:51 2010
+++ /trunk/user/src/com/google/gwt/rpc/server/RpcServlet.java Tue Apr 19
08:27:36 2011
@@ -33,8 +33,8 @@
import java.net.MalformedURLException;
import java.net.URL;
import java.net.UnknownHostException;
-import java.util.HashMap;
import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
import java.util.zip.GZIPOutputStream;
import javax.servlet.ServletException;
@@ -53,7 +53,7 @@
protected static final String CLIENT_ORACLE_EXTENSION = ".gwt.rpc";
private static final boolean DUMP_PAYLOAD =
Boolean.getBoolean("gwt.rpc.dumpPayload");
- private final Map<String, SoftReference<ClientOracle>> clientOracleCache
= new HashMap<String, SoftReference<ClientOracle>>();
+ private final Map<String, SoftReference<ClientOracle>> clientOracleCache
= new ConcurrentHashMap<String, SoftReference<ClientOracle>>();
/**
* The implementation of the service.
@@ -98,6 +98,17 @@
ClientOracle toReturn;
+ // Fast path if the ClientOracle is already cached.
+ if (clientOracleCache.containsKey(permutationStrongName)) {
+ toReturn = clientOracleCache.get(permutationStrongName).get();
+ if (toReturn != null) {
+ return toReturn;
+ }
+ }
+
+ /* Synchronize to make sure expensive calls are executed only once.
+ Double checked locking idiom works here because of volatiles in
+ ConcurrentHashMap.*/
synchronized (clientOracleCache) {
if (clientOracleCache.containsKey(permutationStrongName)) {
toReturn = clientOracleCache.get(permutationStrongName).get();
--
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