java.lang.Object | |
↳ | java.lang.management.MemoryNotificationInfo |
The information about a memory notification.
A memory notification is emitted by MemoryMXBean
when the Java virtual machine detects that the memory usage
of a memory pool is exceeding a threshold value.
The notification emitted will contain the memory notification
information about the detected condition:
usage threshold
count
. For collection threshold notifications,
this count will be the
collection usage threshold count
.
A CompositeData
representing
the MemoryNotificationInfo object
is stored in the
user data
of a notification
.
The from
method is provided to convert from
a CompositeData to a MemoryNotificationInfo
object. For example:
Notification notif; // receive the notification emitted by MemoryMXBean and set to notif ... String notifType = notif.getType(); if (notifType.equals(MemoryNotificationInfo.MEMORY_THRESHOLD_EXCEEDED) || notifType.equals(MemoryNotificationInfo.MEMORY_COLLECTION_THRESHOLD_EXCEEDED)) { // retrieve the memory notification information CompositeData cd = (CompositeData) notif.getUserData(); MemoryNotificationInfo info = MemoryNotificationInfo.from(cd); .... }
The types of notifications emitted by MemoryMXBean are:
usage threshold exceeded notification
.
collection usage threshold exceeded notification
.
Constants | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
String | MEMORY_COLLECTION_THRESHOLD_EXCEEDED | Notification type denoting that the memory usage of a memory pool is greater than or equal to its collection usage threshold after the Java virtual machine has expended effort in recycling unused objects in that memory pool. | |||||||||
String | MEMORY_THRESHOLD_EXCEEDED | Notification type denoting that the memory usage of a memory pool has reached or exceeded its usage threshold value. |
Public Constructors | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Constructs a MemoryNotificationInfo object.
|
Public Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Returns a MemoryNotificationInfo object represented by the
given CompositeData.
| |||||||||||
Returns the number of times that the memory usage has crossed
a threshold when the notification was constructed.
| |||||||||||
Returns the name of the memory pool that triggers this notification.
| |||||||||||
Returns the memory usage of the memory pool
when this notification was constructed.
|
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Inherited Methods | |||||||||||
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From class
java.lang.Object
|
Notification type denoting that
the memory usage of a memory pool is greater than or equal to its
collection usage threshold after the Java virtual machine
has expended effort in recycling unused objects in that
memory pool.
This notification is emitted by MemoryMXBean
.
The value of this notification type is
java.management.memory.collection.threshold.exceeded.
Notification type denoting that
the memory usage of a memory pool has
reached or exceeded its
usage threshold value.
This notification is emitted by MemoryMXBean
.
Subsequent crossing of the usage threshold value does not cause
further notification until the memory usage has returned
to become less than the usage threshold value.
The value of this notification type is
java.management.memory.threshold.exceeded.
Constructs a MemoryNotificationInfo object.
poolName | The name of the memory pool which triggers this notification. |
---|---|
usage | Memory usage of the memory pool. |
count | The threshold crossing count. |
Returns a MemoryNotificationInfo object represented by the given CompositeData. The given CompositeData must contain the following attributes:
Attribute Name Type poolName java.lang.String usage javax.management.openmbean.CompositeData count java.lang.Long
cd | CompositeData representing a MemoryNotificationInfo |
---|
IllegalArgumentException | if cd does not represent a MemoryNotificationInfo object. |
---|
Returns the number of times that the memory usage has crossed
a threshold when the notification was constructed.
For usage threshold notifications, this count will be the
threshold
count
. For collection threshold notifications,
this count will be the
collection usage threshold count
.
Returns the name of the memory pool that triggers this notification. The memory pool usage has crossed a threshold.
Returns the memory usage of the memory pool when this notification was constructed.