HDFS-5000. DataNode configuration should allow specifying storage type (Adding file missed in last commit

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-2832@1517499 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/StorageLocation.java

@@ -0,0 +1,113 @@
+/**
+ * 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.hdfs.server.datanode;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.hdfs.StorageType;
+import org.apache.hadoop.hdfs.server.common.Util;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URI;
+import java.util.regex.Matcher;
+
+import static java.util.regex.Pattern.compile;
+
+/**
+ * Encapsulates the URI and storage medium that together describe a
+ * storage directory.
+ * The default storage medium is assumed to be DISK, if none is specified.
+ *
+ */
+@InterfaceAudience.Private
+public class StorageLocation {
+  public static final Log LOG = LogFactory.getLog(StorageLocation.class);
+  final StorageType storageType;
+  final File file;
+
+  // Regular expression that describes a storage uri with a storage type.
+  // e.g. [Disk]/storages/storage1/
+  private static final String rawStringRegex = "^\\[(\\w*)\\](.+)$";
+
+  StorageLocation(URI uri) {
+    this(StorageType.DISK, uri);
+  }
+
+  StorageLocation(StorageType storageType, URI uri) {
+    this.storageType = storageType;
+
+    if (uri.getScheme() == null ||
+        "file".equalsIgnoreCase(uri.getScheme())) {
+      // drop any (illegal) authority in the URI for backwards compatibility
+      this.file = new File(uri.getPath());
+    } else {
+      throw new IllegalArgumentException(
+          "Got an Unsupported URI schema in " + uri + ". Ignoring ...");
+    }
+  }
+
+  public StorageType getStorageType() {
+    return this.storageType;
+  }
+
+  public URI getUri() {
+    return file.toURI();
+  }
+
+  public File getFile() {
+    return this.file;
+  }
+
+  /**
+   * Attempt to parse a storage uri with storage class and URI. The storage
+   * class component of the uri is case-insensitive.
+   *
+   * @param rawLocation Location string of the format [type]uri, where [type] is
+   *                    optional.
+   * @return A StorageLocation object if successfully parsed, null otherwise.
+   *         Does not throw any exceptions.
+   */
+  public static StorageLocation parse(String rawLocation) throws IOException {
+    Matcher matcher = compile(rawStringRegex).matcher(rawLocation);
+    StorageType storageType = StorageType.DISK;
+    String location = rawLocation;
+
+    if (matcher.matches()) {
+      String classString = matcher.group(1);
+      location = matcher.group(2);
+      if (!classString.isEmpty()) {
+        try {
+          storageType = StorageType.valueOf(classString.toUpperCase());
+        } catch (RuntimeException re) {
+          LOG.error("Unable to parse storage type: " + re.toString() +
+                    ". Using the default storage type for directory " +
+                    location);
+        }
+      }
+    }
+
+    return new StorageLocation(storageType, Util.stringAsURI(location));
+  }
+
+  public String toString() {
+    return "[" + storageType.toString() + "]" + file.toURI().toString();
+  }
+}