001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.camel.management.mbean;
018
019 /**
020 * Default implementation of {@link Statistic}
021 */
022 public class Statistic {
023
024 /**
025 * Statistics mode
026 * <ul>
027 * <li>VALUE - A statistic with this update mode is a simple value that is a straight forward
028 * representation of the updated value.</li>
029 * <li>DIFFERENCE - A statistic with this update mode is a value that represents the difference
030 * between the last two recorded values (or the initial value if two updates have
031 * not been recorded).</li>
032 * <li>DELTA - A statistic with this update mode is a value that represents the delta
033 * between the last two recorded values (or the initial value if two updates have
034 * not been recorded). This value can be negative if the delta goes up or down.</li>
035 * <li>COUNTER - A statistic with this update mode interprets updates as increments (positive values)
036 * or decrements (negative values) to the current value.</li>
037 * <li>MAXIMUM - A statistic with this update mode is a value that represents the maximum value
038 * amongst the update values applied to this statistic.</li>
039 * <li>MINIMUM - A statistic with this update mode is a value that represents the minimum value
040 * amongst the update values applied to this statistic.</li>
041 * <ul>
042 */
043 public enum UpdateMode {
044 VALUE, DIFFERENCE, DELTA, COUNTER, MAXIMUM, MINIMUM
045 }
046
047 private final UpdateMode updateMode;
048 private long lastValue;
049 private long value;
050 private long updateCount;
051
052 /**
053 * Instantiates a new statistic.
054 *
055 * @param name name of statistic
056 * @param owner owner
057 * @param updateMode The statistic update mode.
058 */
059 public Statistic(String name, Object owner, UpdateMode updateMode) {
060 this.updateMode = updateMode;
061 }
062
063 public synchronized void updateValue(long newValue) {
064 switch (this.updateMode) {
065 case COUNTER:
066 this.value += newValue;
067 break;
068 case VALUE:
069 this.value = newValue;
070 break;
071 case DIFFERENCE:
072 this.value -= newValue;
073 if (this.value < 0) {
074 this.value = -this.value;
075 }
076 break;
077 case DELTA:
078 if (updateCount > 0) {
079 this.lastValue = this.value;
080 }
081 this.value = newValue;
082 break;
083 case MAXIMUM:
084 // initialize value at first time
085 if (this.updateCount == 0 || this.value < newValue) {
086 this.value = newValue;
087 }
088 break;
089 case MINIMUM:
090 // initialize value at first time
091 if (this.updateCount == 0 || this.value > newValue) {
092 this.value = newValue;
093 }
094 break;
095 default:
096 }
097 this.updateCount++;
098 }
099
100 public synchronized void increment() {
101 updateValue(1);
102 }
103
104 public synchronized long getValue() {
105 if (updateMode == UpdateMode.DELTA) {
106 if (updateCount == 0) {
107 return this.value;
108 } else {
109 return this.value - this.lastValue;
110 }
111 } else {
112 return this.value;
113 }
114 }
115
116 public synchronized long getUpdateCount() {
117 return this.updateCount;
118 }
119
120 public synchronized void reset() {
121 this.value = 0;
122 this.lastValue = 0;
123 this.updateCount = 0;
124 }
125
126 public String toString() {
127 return "" + value;
128 }
129
130 }