| /* |
| * Copyright 2014-present Open Networking Foundation |
| * |
| * Licensed 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.onlab.util; |
| |
| import java.util.Objects; |
| |
| import static com.google.common.base.MoreObjects.toStringHelper; |
| import static com.google.common.base.Preconditions.checkArgument; |
| |
| /** |
| * Counting mechanism capable of tracking occurrences and rates. |
| */ |
| public class Counter { |
| |
| private long total = 0; |
| private long start = System.currentTimeMillis(); |
| private long end = 0; |
| |
| /** |
| * Creates a new counter. |
| */ |
| public Counter() { |
| } |
| |
| /** |
| * Creates a new counter in a specific state. If non-zero end time is |
| * specified, the counter will be frozen. |
| * |
| * @param start start time |
| * @param total total number of items to start with |
| * @param end end time; if non-ze |
| */ |
| public Counter(long start, long total, long end) { |
| checkArgument(start <= end, "Malformed interval: start > end"); |
| checkArgument(total >= 0, "Total must be non-negative"); |
| this.start = start; |
| this.total = total; |
| this.end = end; |
| } |
| |
| /** |
| * Resets the counter, by zeroing out the count and restarting the timer. |
| */ |
| public synchronized void reset() { |
| end = 0; |
| total = 0; |
| start = System.currentTimeMillis(); |
| } |
| |
| /** |
| * Freezes the counter in the current state including the counts and times. |
| */ |
| public synchronized void freeze() { |
| end = System.currentTimeMillis(); |
| } |
| |
| /** |
| * Adds the specified number of occurrences to the counter. No-op if the |
| * counter has been frozen. |
| * |
| * @param count number of occurrences |
| */ |
| public synchronized void add(long count) { |
| checkArgument(count >= 0, "Count must be non-negative"); |
| if (end == 0L) { |
| total += count; |
| } |
| } |
| |
| /** |
| * Returns the number of occurrences per second. |
| * |
| * @return throughput in occurrences per second |
| */ |
| public synchronized double throughput() { |
| return total / duration(); |
| } |
| |
| /** |
| * Returns the total number of occurrences counted. |
| * |
| * @return number of counted occurrences |
| */ |
| public synchronized long total() { |
| return total; |
| } |
| |
| /** |
| * Returns the duration expressed in fractional number of seconds. |
| * |
| * @return fractional number of seconds since the last reset |
| */ |
| public synchronized double duration() { |
| // Protect against 0 return by artificially setting duration to 1ms |
| long duration = (end == 0L ? System.currentTimeMillis() : end) - start; |
| return (duration == 0 ? 1 : duration) / 1000.0; |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hash(total, start, end); |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) { |
| return true; |
| } |
| if (obj instanceof Counter) { |
| final Counter other = (Counter) obj; |
| return Objects.equals(this.total, other.total) && |
| Objects.equals(this.start, other.start) && |
| Objects.equals(this.end, other.end); |
| } |
| return false; |
| } |
| |
| @Override |
| public String toString() { |
| return toStringHelper(this) |
| .add("total", total) |
| .add("start", start) |
| .add("end", end) |
| .toString(); |
| } |
| } |