1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 package com.yammer.metrics.core;
20
21 import com.yammer.metrics.stats.Snapshot;
22
23 /**
24 * An empty Metrics' Histogram that does nothing.
25 */
26 public class NoOpHistogram extends Histogram {
27 /** singleton instance for everyone to use */
28 public static final NoOpHistogram INSTANCE = new NoOpHistogram();
29
30 /** do not instantiate */
31 private NoOpHistogram() { super(SampleType.UNIFORM); }
32
33 @Override
34 public void clear() { }
35
36 @Override
37 public void update(int value) { }
38
39 @Override
40 public void update(long value) { }
41
42 @Override
43 public long count() { return 0; }
44
45 @Override
46 public double max() { return 0.0; }
47
48 @Override
49 public double min() { return 0.0; }
50
51 @Override
52 public double mean() { return 0.0; }
53
54 @Override
55 public double stdDev() { return 0.0; }
56
57 @Override
58 public double sum() { return 0.0; }
59
60 @Override
61 public Snapshot getSnapshot() { return new Snapshot(new double[0]); }
62
63 @Override
64 public <T> void processWith(MetricProcessor<T> processor, MetricName name,
65 T context)
66 throws Exception { }
67 }