001/* MemoryNotificationInfo.java - Emitted memory notification info. 002 Copyright (C) 2006 Free Software Foundation 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038package java.lang.management; 039 040import gnu.java.lang.management.MemoryMXBeanImpl; 041 042import javax.management.openmbean.CompositeData; 043import javax.management.openmbean.CompositeType; 044import javax.management.openmbean.SimpleType; 045 046/** 047 * <p> 048 * Represents the content of a notification emitted by the 049 * {@link MemoryMXBean}. Such notifications are emitted when 050 * one of the memory pools exceeds its usage or collection 051 * usage threshold. This object contains the following information, 052 * representing the state of the pool at the time of the 053 * notification: 054 * </p> 055 * <ul> 056 * <li>The name of the pool.</li> 057 * <li>The memory usage of the pool at the time of notification.</li> 058 * <li>The number of times the pool has exceeded this particular 059 * threshold in the past.</li> 060 * </ul> 061 * <p> 062 * Two types of notification are emitted by the {@link MemoryMXBean}: 063 * one for exceeding the usage threshold and one for exceeding the 064 * collection usage threshold. The value returned by {@link #getCount()} 065 * is dependent on this type; if the threshold exceeded is the usage 066 * threshold, then the usage threshold count is returned. If, instead, 067 * the collection usage threshold is exceeded, then the collection usage 068 * threshold count is returned. 069 * </p> 070 * <p> 071 * This data is held in the user data part of the notification (returned 072 * by {@link javax.management.Notification#getUserData()}) encapsulated in 073 * a {@link javax.management.openmbean.CompositeData} object. The 074 * {@link #from(javax.management.openmbean.CompositeData)} method may be 075 * used to unwrap the value and obtain an instance of this class. 076 * </p> 077 * 078 * @author Andrew John Hughes (gnu_andrew@member.fsf.org) 079 * @since 1.5 080 */ 081public class MemoryNotificationInfo 082{ 083 084 /** 085 * The type of notification emitted when the usage threshold is exceeded. 086 * After a notification is emitted, the usage level must drop below the 087 * threshold again before another notification is emitted. The value is 088 * <code>java.management.memory.threshold.exceeded</code>. 089 */ 090 public static final String MEMORY_THRESHOLD_EXCEEDED = 091 "java.management.memory.threshold.exceeded"; 092 093 /** 094 * The type of notification emitted when the collection usage threshold 095 * is exceeded, following a garbage collection cycle. The value is 096 * <code>java.management.memory.collection.threshold.exceeded</code>. 097 */ 098 public static final String MEMORY_COLLECTION_THRESHOLD_EXCEEDED = 099 "java.management.memory.collection.threshold.exceeded"; 100 101 /** 102 * The name of the memory pool which exceeded the threshold. 103 */ 104 private String poolName; 105 106 /** 107 * The usage level of the memory pool at the time of notification. 108 */ 109 private MemoryUsage usage; 110 111 /** 112 * The number of times the threshold has been crossed. 113 */ 114 private long count; 115 116 /** 117 * Constructs a new {@link MemoryNotificationInfo} object using the 118 * specified pool name, usage level and threshold crossing count. 119 * 120 * @param poolName the name of the pool which has exceeded a threshold. 121 * @param usage the usage level of the pool at the time of notification. 122 * @param count the number of times the threshold has been crossed. 123 */ 124 public MemoryNotificationInfo(String poolName, MemoryUsage usage, long count) 125 { 126 this.poolName = poolName; 127 this.usage = usage; 128 this.count = count; 129 } 130 131 /** 132 * <p> 133 * Returns a {@link MemoryNotificationInfo} instance using the values 134 * given in the supplied 135 * {@link javax.management.openmbean.CompositeData} object. 136 * The composite data instance should contain the following 137 * attributes with the specified types: 138 * </p> 139 * <table> 140 * <th><td>Name</td><td>Type</td></th> 141 * <tr><td>poolName</td><td>java.lang.String</td></tr> 142 * <tr><td>usage</td><td>javax.management.openmbean.CompositeData 143 * </td></tr> 144 * <tr><td>count</td><td>java.lang.Long</td></tr> 145 * </table> 146 * <p> 147 * The usage level is further described as: 148 * </p> 149 * <table> 150 * <th><td>Name</td><td>Type</td></th> 151 * <tr><td>init</td><td>java.lang.Long</td></tr> 152 * <tr><td>used</td><td>java.lang.Long</td></tr> 153 * <tr><td>committed</td><td>java.lang.Long</td></tr> 154 * <tr><td>max</td><td>java.lang.Long</td></tr> 155 * </table> 156 * 157 * @param data the composite data structure to take values from. 158 * @return a new instance containing the values from the 159 * composite data structure, or <code>null</code> 160 * if the data structure was also <code>null</code>. 161 * @throws IllegalArgumentException if the composite data structure 162 * does not match the structure 163 * outlined above. 164 */ 165 public static MemoryNotificationInfo from(CompositeData data) 166 { 167 if (data == null) 168 return null; 169 CompositeType type = data.getCompositeType(); 170 ThreadInfo.checkAttribute(type, "poolName", SimpleType.STRING); 171 ThreadInfo.checkAttribute(type, "usage", MemoryMXBeanImpl.usageType); 172 ThreadInfo.checkAttribute(type, "count", SimpleType.LONG); 173 MemoryUsage usage = MemoryUsage.from((CompositeData) data.get("usage")); 174 return new MemoryNotificationInfo(((String) data.get("poolName")), 175 usage, 176 ((Long) data.get("count")).longValue()); 177 } 178 179 /** 180 * Returns the number of times the memory pool has crossed the usage 181 * threshold, as of the time of notification. If this is the notification 182 * represented by the type {@link #MEMORY_THRESHOLD_EXCEEDED}, then the 183 * count is the usage threshold count. If this is the notification 184 * represented by the type {@link #MEMORY_COLLECTION_THRESHOLD_EXCEEDED}, 185 * then the count is the collection usage threshold count. 186 * 187 * @return the number of times the appropriate threshold has been crossed. 188 */ 189 public long getCount() 190 { 191 return count; 192 } 193 194 /** 195 * Returns the name of the pool which has crossed a threshold. 196 * 197 * @return the name of the pool. 198 */ 199 public String getPoolName() 200 { 201 return poolName; 202 } 203 204 /** 205 * Returns the usage levels at the time of notification. 206 * 207 * @return the usage levels. 208 */ 209 public MemoryUsage getUsage() 210 { 211 return usage; 212 } 213 214} 215