| /** |
| * 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.checker; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| |
| /** |
| * A Checkable is an object whose health can be probed by invoking its |
| * {@link #check} method. |
| * |
| * e.g. a {@link Checkable} instance may represent a single hardware |
| * resource. |
| */ |
| @InterfaceAudience.Private |
| @InterfaceStability.Unstable |
| public interface Checkable<K, V> { |
| |
| /** |
| * Query the health of this object. This method may hang |
| * indefinitely depending on the status of the target resource. |
| * |
| * @param context for the probe operation. May be null depending |
| * on the implementation. |
| * |
| * @return result of the check operation. |
| * |
| * @throws Exception encountered during the check operation. An |
| * exception indicates that the check failed. |
| */ |
| V check(K context) throws Exception; |
| } |