This project has retired. For details please refer to its Attic page.
AggregatedMetric xref
View Javadoc

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 org.apache.giraph.metrics;
20  
21  /**
22   * An aggregator over metrics from multiple hosts. Computes min, max, and mean.
23   *
24   * @param <T> value type
25   */
26  public abstract class AggregatedMetric<T extends Number> {
27    /** Minimum value seen with the host that it came from */
28    protected ValueWithHostname<T> min;
29    /** Maximum value seen with the host that it came from */
30    protected ValueWithHostname<T> max;
31    /** Total of all the values seen */
32    protected T sum;
33    /** Number of values seen */
34    protected long count;
35  
36    /**
37     * Add another item to the aggregation.
38     *
39     * @param value value to add
40     * @param hostnamePartitionId String hostname it came from
41     */
42    public abstract void addItem(T value, String hostnamePartitionId);
43  
44    /**
45     * Whether this AggregatedMetric has any data.
46     *
47     * @return true if we have any data.
48     */
49    public boolean hasData() {
50      return count > 0;
51    }
52  
53    /**
54     * Get minimum value together with host it came from.
55     *
56     * @return ValueWithHostname for minimum
57     */
58    public ValueWithHostname<T> min() {
59      return min;
60    }
61  
62    /**
63     * Get maximum value together with host it came from.
64     *
65     * @return ValueWithHostname for maximum
66     */
67    public ValueWithHostname<T> max() {
68      return max;
69    }
70  
71    /**
72     * Get total of all the values seen
73     *
74     * @return total of values seen
75     */
76    public T sum() {
77      return sum;
78    }
79  
80    /**
81     * Get average of all the values
82     *
83     * @return computed average of all the values
84     */
85    public abstract double mean();
86  
87    /**
88     * Get number of values seen
89     *
90     * @return count of values
91     */
92    public long count() {
93      return count;
94    }
95  }
96