svn commit: r1516669 - /hadoop/common/branches/HDFS-4949/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/Fallible.java

[cm...@apache.org]

Author: cmccabe
Date: Thu Aug 22 23:37:51 2013
New Revision: 1516669

URL: http://svn.apache.org/r1516669
Log:
HDFS-5052. Add cacheRequest/uncacheRequest support to NameNode.  (Contributed by Colin Patrick McCabe.)

Added:
    hadoop/common/branches/HDFS-4949/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/Fallible.java

Added: hadoop/common/branches/HDFS-4949/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/Fallible.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-4949/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/Fallible.java?rev=1516669&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-4949/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/Fallible.java (added)
+++ hadoop/common/branches/HDFS-4949/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/Fallible.java Thu Aug 22 23:37:51 2013
@@ -0,0 +1,53 @@
+/**
+ * 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.util;
+
+import java.io.IOException;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+
+/**
+ * Contains either a value of type T, or an IOException.
+ *
+ * This can be useful as a return value for batch APIs that need granular
+ * error reporting.
+ */
+@InterfaceAudience.LimitedPrivate({"HDFS"})
+@InterfaceStability.Unstable
+public class Fallible<T> {
+  private final T val;
+  private final IOException ioe;
+
+  public Fallible(T val) {
+    this.val = val;
+    this.ioe = null;
+  }
+
+  public Fallible(IOException ioe) {
+    this.val = null;
+    this.ioe = ioe;
+  }
+
+  public T get() throws IOException {
+    if (ioe != null) {
+      throw new IOException(ioe);
+    }
+    return this.val;
+  }
+}