/* | |
* MetricsContext.java | |
* | |
* 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.metrics; | |
import java.io.IOException; | |
import java.util.Collection; | |
import java.util.Map; | |
import org.apache.hadoop.classification.InterfaceAudience; | |
import org.apache.hadoop.classification.InterfaceStability; | |
import org.apache.hadoop.metrics.spi.OutputRecord; | |
/** | |
* The main interface to the metrics package. | |
* @deprecated in favor of <code>org.apache.hadoop.metrics2</code> usage. | |
*/ | |
@Deprecated | |
@InterfaceAudience.Private | |
@InterfaceStability.Evolving | |
public interface MetricsContext { | |
/** | |
* Default period in seconds at which data is sent to the metrics system. | |
*/ | |
public static final int DEFAULT_PERIOD = 5; | |
/** | |
* Initialize this context. | |
* @param contextName The given name for this context | |
* @param factory The creator of this context | |
*/ | |
public void init(String contextName, ContextFactory factory); | |
/** | |
* Returns the context name. | |
* | |
* @return the context name | |
*/ | |
public abstract String getContextName(); | |
/** | |
* Starts or restarts monitoring, the emitting of metrics records as they are | |
* updated. | |
*/ | |
public abstract void startMonitoring() | |
throws IOException; | |
/** | |
* Stops monitoring. This does not free any data that the implementation | |
* may have buffered for sending at the next timer event. It | |
* is OK to call <code>startMonitoring()</code> again after calling | |
* this. | |
* @see #close() | |
*/ | |
public abstract void stopMonitoring(); | |
/** | |
* Returns true if monitoring is currently in progress. | |
*/ | |
public abstract boolean isMonitoring(); | |
/** | |
* Stops monitoring and also frees any buffered data, returning this | |
* object to its initial state. | |
*/ | |
public abstract void close(); | |
/** | |
* Creates a new MetricsRecord instance with the given <code>recordName</code>. | |
* Throws an exception if the metrics implementation is configured with a fixed | |
* set of record names and <code>recordName</code> is not in that set. | |
* | |
* @param recordName the name of the record | |
* @throws MetricsException if recordName conflicts with configuration data | |
*/ | |
public abstract MetricsRecord createRecord(String recordName); | |
/** | |
* Registers a callback to be called at regular time intervals, as | |
* determined by the implementation-class specific configuration. | |
* | |
* @param updater object to be run periodically; it should updated | |
* some metrics records and then return | |
*/ | |
public abstract void registerUpdater(Updater updater); | |
/** | |
* Removes a callback, if it exists. | |
* | |
* @param updater object to be removed from the callback list | |
*/ | |
public abstract void unregisterUpdater(Updater updater); | |
/** | |
* Returns the timer period. | |
*/ | |
public abstract int getPeriod(); | |
/** | |
* Retrieves all the records managed by this MetricsContext. | |
* Useful for monitoring systems that are polling-based. | |
* | |
* @return A non-null map from all record names to the records managed. | |
*/ | |
Map<String, Collection<OutputRecord>> getAllRecords(); | |
} |