001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    
019    package org.apache.hadoop.metrics2;
020    
021    import java.io.Closeable;
022    
023    import org.apache.hadoop.classification.InterfaceAudience;
024    import org.apache.hadoop.classification.InterfaceStability;
025    
026    /**
027     * The metrics sink interface. <p>
028     * Implementations of this interface consume the {@link MetricsRecord} generated
029     * from {@link MetricsSource}. It registers with {@link MetricsSystem} which
030     * periodically pushes the {@link MetricsRecord} to the sink using
031     * {@link #putMetrics(MetricsRecord)} method.  If the implementing class also
032     * implements {@link Closeable}, then the MetricsSystem will close the sink when
033     * it is stopped.
034     */
035    @InterfaceAudience.Public
036    @InterfaceStability.Evolving
037    public interface MetricsSink extends MetricsPlugin {
038      /**
039       * Put a metrics record in the sink
040       * @param record  the record to put
041       */
042      void putMetrics(MetricsRecord record);
043    
044      /**
045       * Flush any buffered metrics
046       */
047      void flush();
048    }