/**
* 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;
}