You are viewing a plain text version of this content. The canonical link for it is here.
Posted to common-commits@hadoop.apache.org by dd...@apache.org on 2008/08/05 08:12:09 UTC
svn commit: r682593 -
/hadoop/core/trunk/src/core/org/apache/hadoop/net/CachedDNSToSwitchMapping.java
Author: ddas
Date: Mon Aug 4 23:12:08 2008
New Revision: 682593
URL: http://svn.apache.org/viewvc?rev=682593&view=rev
Log:
HADOOP-3620. Added the file CacheDNSToSwitchMapping.java that was missed earlier.
Added:
hadoop/core/trunk/src/core/org/apache/hadoop/net/CachedDNSToSwitchMapping.java
Added: hadoop/core/trunk/src/core/org/apache/hadoop/net/CachedDNSToSwitchMapping.java
URL: http://svn.apache.org/viewvc/hadoop/core/trunk/src/core/org/apache/hadoop/net/CachedDNSToSwitchMapping.java?rev=682593&view=auto
==============================================================================
--- hadoop/core/trunk/src/core/org/apache/hadoop/net/CachedDNSToSwitchMapping.java (added)
+++ hadoop/core/trunk/src/core/org/apache/hadoop/net/CachedDNSToSwitchMapping.java Mon Aug 4 23:12:08 2008
@@ -0,0 +1,80 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.net;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * A cached implementation of DNSToSwitchMapping that takes an
+ * raw DNSToSwitchMapping and stores the resolved network location in
+ * a cache. The following calls to a resolved network location
+ * will get its location from the cache.
+ *
+ */
+public class CachedDNSToSwitchMapping implements DNSToSwitchMapping {
+ private Map<String, String> cache = new TreeMap<String, String>();
+ protected DNSToSwitchMapping rawMapping;
+
+ public CachedDNSToSwitchMapping(DNSToSwitchMapping rawMapping) {
+ this.rawMapping = rawMapping;
+ }
+
+ public List<String> resolve(List<String> names) {
+ // normalize all input names to be in the form of IP addresses
+ names = NetUtils.normalizeHostNames(names);
+
+ List <String> result = new ArrayList<String>(names.size());
+ if (names.isEmpty()) {
+ return result;
+ }
+
+
+ // find out all names without cached resolved location
+ List<String> unCachedHosts = new ArrayList<String>(names.size());
+ for (String name : names) {
+ if (cache.get(name) == null) {
+ unCachedHosts.add(name);
+ }
+ }
+
+ // Resolve those names
+ List<String> rNames = rawMapping.resolve(unCachedHosts);
+
+ // Cache the result
+ if (rNames != null) {
+ for (int i=0; i<unCachedHosts.size(); i++) {
+ cache.put(unCachedHosts.get(i), rNames.get(i));
+ }
+ }
+
+ // Construct the result
+ for (String name : names) {
+ //now everything is in the cache
+ String networkLocation = cache.get(name);
+ if (networkLocation != null) {
+ result.add(networkLocation);
+ } else { //resolve all or nothing
+ return null;
+ }
+ }
+ return result;
+ }
+}