/**
* 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.fs.slive;
import java.util.List;
import org.apache.hadoop.fs.FileSystem;
/**
* Operation which wraps a given operation and allows an observer to be notified
* when the operation is about to start and when the operation has finished
*/
class ObserveableOp extends Operation {
/**
* The observation interface which class that wish to monitor starting and
* ending events must implement.
*/
interface Observer {
void notifyStarting(Operation op);
void notifyFinished(Operation op);
}
private Operation op;
private Observer observer;
ObserveableOp(Operation op, Observer observer) {
super(op.getType(), op.getConfig(), op.getRandom());
this.op = op;
this.observer = observer;
}
/**
* Proxy to underlying operation toString()
*/
public String toString() {
return op.toString();
}
@Override // Operation
List<OperationOutput> run(FileSystem fs) {
List<OperationOutput> result = null;
try {
if (observer != null) {
observer.notifyStarting(op);
}
result = op.run(fs);
} finally {
if (observer != null) {
observer.notifyFinished(op);
}
}
return result;
}
}