Thomas Vachuska | 24c849c | 2014-10-27 09:53:05 -0700 | [diff] [blame] | 1 | /* |
Brian O'Connor | 5ab426f | 2016-04-09 01:19:45 -0700 | [diff] [blame] | 2 | * Copyright 2014-present Open Networking Laboratory |
Thomas Vachuska | 24c849c | 2014-10-27 09:53:05 -0700 | [diff] [blame] | 3 | * |
Thomas Vachuska | 4f1a60c | 2014-10-28 13:39:07 -0700 | [diff] [blame] | 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
Thomas Vachuska | 24c849c | 2014-10-27 09:53:05 -0700 | [diff] [blame] | 7 | * |
Thomas Vachuska | 4f1a60c | 2014-10-28 13:39:07 -0700 | [diff] [blame] | 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
Thomas Vachuska | 24c849c | 2014-10-27 09:53:05 -0700 | [diff] [blame] | 15 | */ |
tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 16 | package org.onlab.util; |
| 17 | |
| 18 | import java.util.Objects; |
| 19 | |
| 20 | import static com.google.common.base.MoreObjects.toStringHelper; |
| 21 | import static com.google.common.base.Preconditions.checkArgument; |
| 22 | |
| 23 | /** |
| 24 | * Counting mechanism capable of tracking occurrences and rates. |
| 25 | */ |
| 26 | public class Counter { |
| 27 | |
| 28 | private long total = 0; |
| 29 | private long start = System.currentTimeMillis(); |
| 30 | private long end = 0; |
| 31 | |
| 32 | /** |
| 33 | * Creates a new counter. |
| 34 | */ |
| 35 | public Counter() { |
| 36 | } |
| 37 | |
| 38 | /** |
| 39 | * Creates a new counter in a specific state. If non-zero end time is |
| 40 | * specified, the counter will be frozen. |
| 41 | * |
| 42 | * @param start start time |
| 43 | * @param total total number of items to start with |
| 44 | * @param end end time; if non-ze |
| 45 | */ |
| 46 | public Counter(long start, long total, long end) { |
| 47 | checkArgument(start <= end, "Malformed interval: start > end"); |
| 48 | checkArgument(total >= 0, "Total must be non-negative"); |
| 49 | this.start = start; |
| 50 | this.total = total; |
| 51 | this.end = end; |
| 52 | } |
| 53 | |
| 54 | /** |
| 55 | * Resets the counter, by zeroing out the count and restarting the timer. |
| 56 | */ |
| 57 | public synchronized void reset() { |
| 58 | end = 0; |
| 59 | total = 0; |
| 60 | start = System.currentTimeMillis(); |
| 61 | } |
| 62 | |
| 63 | /** |
| 64 | * Freezes the counter in the current state including the counts and times. |
| 65 | */ |
| 66 | public synchronized void freeze() { |
| 67 | end = System.currentTimeMillis(); |
| 68 | } |
| 69 | |
| 70 | /** |
| 71 | * Adds the specified number of occurrences to the counter. No-op if the |
| 72 | * counter has been frozen. |
| 73 | * |
| 74 | * @param count number of occurrences |
| 75 | */ |
| 76 | public synchronized void add(long count) { |
| 77 | checkArgument(count >= 0, "Count must be non-negative"); |
| 78 | if (end == 0L) { |
| 79 | total += count; |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Returns the number of occurrences per second. |
| 85 | * |
| 86 | * @return throughput in occurrences per second |
| 87 | */ |
| 88 | public synchronized double throughput() { |
| 89 | return total / duration(); |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * Returns the total number of occurrences counted. |
| 94 | * |
| 95 | * @return number of counted occurrences |
| 96 | */ |
| 97 | public synchronized long total() { |
| 98 | return total; |
| 99 | } |
| 100 | |
| 101 | /** |
| 102 | * Returns the duration expressed in fractional number of seconds. |
| 103 | * |
| 104 | * @return fractional number of seconds since the last reset |
| 105 | */ |
| 106 | public synchronized double duration() { |
| 107 | // Protect against 0 return by artificially setting duration to 1ms |
| 108 | long duration = (end == 0L ? System.currentTimeMillis() : end) - start; |
| 109 | return (duration == 0 ? 1 : duration) / 1000.0; |
| 110 | } |
| 111 | |
| 112 | @Override |
| 113 | public int hashCode() { |
| 114 | return Objects.hash(total, start, end); |
| 115 | } |
| 116 | |
| 117 | @Override |
| 118 | public boolean equals(Object obj) { |
| 119 | if (this == obj) { |
| 120 | return true; |
| 121 | } |
| 122 | if (obj instanceof Counter) { |
| 123 | final Counter other = (Counter) obj; |
| 124 | return Objects.equals(this.total, other.total) && |
| 125 | Objects.equals(this.start, other.start) && |
| 126 | Objects.equals(this.end, other.end); |
| 127 | } |
| 128 | return false; |
| 129 | } |
| 130 | |
| 131 | @Override |
| 132 | public String toString() { |
| 133 | return toStringHelper(this) |
| 134 | .add("total", total) |
| 135 | .add("start", start) |
| 136 | .add("end", end) |
| 137 | .toString(); |
| 138 | } |
| 139 | } |