HBASE-603 When an exception bubbles out of getRegionServerWithRetries, wrap the exception with a RetriesExhaustedException

-Added RetriesExhaustedException to client package
-HTable now throws REE when retries run out

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@652185 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -30,6 +30,8 @@ Hbase Change Log
    HBASE-596   DemoClient.py (Ivan Begtin via Stack)
    HBASE-581   Allow adding filters to TableInputFormat (At same time, ensure TIF
                is subclassable) (David Alves via Stack)
+   HBASE-603   When an exception bubbles out of getRegionServerWithRetries, wrap 
+               the exception with a RetriesExhaustedException
 
 Release 0.1.1 - 04/11/2008
 

src/java/org/apache/hadoop/hbase/client/HTable.java

@@ -835,7 +835,7 @@ public class HTable implements HConstants {
    */
   protected <T> T getRegionServerWithRetries(ServerCallable<T> callable) 
   throws IOException, RuntimeException {
-    List<IOException> exceptions = new ArrayList<IOException>();
+    List<Exception> exceptions = new ArrayList<Exception>();
     for(int tries = 0; tries < numRetries; tries++) {
       try {
         callable.instantiateServer(tries != 0);
@@ -845,20 +845,10 @@ public class HTable implements HConstants {
           e = RemoteExceptionHandler.decodeRemoteException((RemoteException) e);
         }
         if (tries == numRetries - 1) {
-          if (LOG.isDebugEnabled()) {
-            String message = "Trying to contact region server for row '" + 
-              callable.row + "', but failed after " + (tries + 1)  + 
-              " attempts.\n";
-            int i = 1;
-            for (IOException e2 : exceptions) {
-              message = message + "Exception " + i++ + ":\n" + e2;
-            }
-            LOG.debug(message);
-          }
-          throw e;
+          throw new RetriesExhaustedException(callable.row, tries, exceptions);
         }
+        exceptions.add(e);
         if (LOG.isDebugEnabled()) {
-          exceptions.add(e);
           LOG.debug("reloading table servers because: " + e.getMessage());
         }
       } catch (Exception e) {

src/java/org/apache/hadoop/hbase/client/RetriesExhaustedException.java

@@ -0,0 +1,48 @@
+/**
+ * Copyright 2008 The Apache Software Foundation
+ *
+ * Licensed 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.hbase.client;
+
+import java.io.IOException; 
+import java.util.List;
+import org.apache.hadoop.io.Text;
+
+/** 
+ * Exception thrown by HTable methods when an attempt to do something (like
+ * commit changes) fails after a bunch of retries. 
+ */ 
+public class RetriesExhaustedException extends IOException {
+  /** 
+   * Create a new RetriesExhaustedException from the list of prior failures.
+   * @param row The row we were pursuing when we ran out of retries
+   * @param numTries The number of tries we made
+   * @param exceptions List of exceptions that failed before giving up
+   */ 
+  public RetriesExhaustedException(Text row, int numTries, 
+    List<Exception> exceptions) {
+    super(getMessage(row, numTries, exceptions));
+  }
+  
+  private static String getMessage(Text row, int numTries, 
+    List<Exception> exceptions) {
+    String buffer = "Trying to contact region server for row '" + 
+      row + "', but failed after " + (numTries + 1)  + " attempts.\nExceptions:\n";
+
+    for (Exception e : exceptions) {
+      buffer += e.toString() + "\n";
+    }
+    return buffer;
+  }
+}