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public interface NetworkServerMBean
This is an MBean defining a JMX management and monitoring interface of Derby's Network Server.
This MBean is created and registered automatically at Network Server startup if all requirements are met (J2SE 5.0 or better).
Key properties for the registered MBean:
type=NetworkServer
system=
runtime system identifier (see description of package org.apache.derby.mbeans)
If a security manager is installed, accessing attributes and operations of this MBean may require a
SystemPermission
; see individual method documentation for details.For more information on Managed Beans, refer to the JMX specification.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description int
getAccumulatedConnectionCount()
Gets the accumulated number of connections.int
getActiveConnectionCount()
Gets the number of currently active connections.long
getBytesReceived()
Gets the total number of bytes read by the server since it was started.int
getBytesReceivedPerSecond()
Gets the number of bytes received per second by the Network Server.long
getBytesSent()
Gets the total number of bytes written by the server since it was started.int
getBytesSentPerSecond()
Gets the number of bytes sent per second by the Network Server.int
getConnectionCount()
Gets the total number of current connections (waiting or active) to the Network Server.int
getConnectionThreadPoolSize()
Get the size of the connection thread pool.String
getDrdaHost()
Gets the network interface address on which the Network Server is listening.boolean
getDrdaKeepAlive()
Reports whether or not the Derby Network Server will send keep-alive probes and attempt to clean up connections for disconnected clients (the value of thederby.drda.keepAlive
property).int
getDrdaMaxThreads()
Reports the maximum number of client connection threads the Network Server will allocate at any given time.int
getDrdaPortNumber()
Gets the port number on which the Network Server is listening for client connections.String
getDrdaSecurityMechanism()
The Derby security mechanism required by the Network Server for all client connections.String
getDrdaSslMode()
Reports whether client connections must be encrypted using Secure Sockets Layer (SSL), and whether certificate based peer authentication is enabled.int
getDrdaStreamOutBufferSize()
The size of the buffer used for streaming BLOB and CLOB from server to client.int
getDrdaTimeSlice()
If the server propertyderby.drda.maxThreads
is set to a non-zero value, this is the number of milliseconds that each client connection will actively use in the Network Server before yielding to another connection.boolean
getDrdaTraceAll()
Whether server-side tracing is enabled for all client connections (sessions).String
getDrdaTraceDirectory()
Indicates the location of tracing files on the server host, if server tracing has been enabled.long
getStartTime()
Gets the start time of the network server.long
getUptime()
Gets the time (in milliseconds) the Network Server has been running.int
getWaitingConnectionCount()
Gets the number of currently waiting connections.void
ping()
Executes the network server'sping
command.
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Method Detail
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getDrdaHost
String getDrdaHost()
Gets the network interface address on which the Network Server is listening. This corresponds to the value of the
derby.drda.host
property.For example, the value "
localhost
" means that the Network Server is listening on the local loopback interface only.The special value "
0.0.0.0
" (IPv4 environments only) represents the "unspecified address" - also known as the anylocal or wildcard address. In this context this means that the server is listening on all network interfaces (and may thus be able to see connections from both the local host as well as remote hosts, depending on which network interfaces are available).Requires
SystemPermission("server", "control")
if a security manager is installed.- Returns:
- the the network interface address on which the Network Server is
listening (
derby.drda.host
)
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getDrdaKeepAlive
boolean getDrdaKeepAlive()
Reports whether or not the Derby Network Server will send keep-alive probes and attempt to clean up connections for disconnected clients (the value of the
derby.drda.keepAlive
property).If
true
, a keep-alive probe is sent to the client if a "long time" (by default, more than two hours) passes with no other data being sent or received. This will detect and clean up connections for clients on powered-off machines or clients that have disconnected unexpectedly.If
false
, Derby will not attempt to clean up connections from disconnected clients, and will not send keep-alive probes.Requires
SystemPermission("server", "monitor")
if a security manager is installed.See also the documentation for the property
derby.drda.keepAlive
in the Derby Server and Administration Guide, section Managing the Derby Network Server, subsection Setting Network Server Properties, subsubsection derby.drda.keepAlive property.- Returns:
true
if Derby Network Server will send keep-alive probes and attempt to clean up connections for disconnected clients (derby.drda.keepAlive
)
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getDrdaMaxThreads
int getDrdaMaxThreads()
Reports the maximum number of client connection threads the Network Server will allocate at any given time. This corresponds to the
derby.drda.maxThreads
property.Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the maximum number of client connection threads the Network
Server will allocate at any given time
(
derby.drda.maxThreads
)
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getDrdaPortNumber
int getDrdaPortNumber()
Gets the port number on which the Network Server is listening for client connections. This corresponds to the value of the
derby.drda.portNumber
Network Server setting.Requires
SystemPermission("server", "control")
if a security manager is installed.- Returns:
- the port number on which the Network Server is listening for client connections.
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getDrdaSecurityMechanism
String getDrdaSecurityMechanism()
The Derby security mechanism required by the Network Server for all client connections. This corresponds to the value of the
derby.drda.securityMechanism
property on the server.If not set, the empty String will be returned, which means that the Network Server accepts any connection which uses a valid security mechanism.
For a list of valid security mechanisms, refer to the documentation for the
derby.drda.securityMechanism
property in the Derby Server and Administration Guide.Requires
SystemPermission("server", "control")
if a security manager is installed.- Returns:
- the security mechanism required by the Network Server for all
client connections (
derby.drda.securityMechanism
)
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getDrdaSslMode
String getDrdaSslMode()
Reports whether client connections must be encrypted using Secure Sockets Layer (SSL), and whether certificate based peer authentication is enabled. Refers to the
derby.drda.sslMode
property.Peer authentication means that the other side of the SSL connection is authenticated based on a trusted certificate installed locally.
The value returned is one of "
off
" (no SSL encryption), "basic
" (SSL encryption, no peer authentication) and "peerAuthentication
" (SSL encryption and peer authentication). Refer to the Derby Server and Administration Guide for more details.Requires
SystemPermission("server", "control")
if a security manager is installed.- Returns:
- whether client connections must be encrypted using Secure
Sockets Layer (SSL), and whether certificate based peer
authentication is enabled (
derby.drda.sslMode
)
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getDrdaStreamOutBufferSize
int getDrdaStreamOutBufferSize()
The size of the buffer used for streaming BLOB and CLOB from server to client. Refers to the
derby.drda.streamOutBufferSize
property.This setting may improve streaming performance when the default sizes of packets being sent are significantly smaller than the maximum allowed packet size in the network.
Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the size of the buffer used for streaming blob/clob from server
to client (
derby.drda.streamOutBufferSize
)
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getDrdaTimeSlice
int getDrdaTimeSlice()
If the server property
derby.drda.maxThreads
is set to a non-zero value, this is the number of milliseconds that each client connection will actively use in the Network Server before yielding to another connection. If this value is 0, a waiting connection will become active once a currently active connection is closed.Refers to the
derby.drda.timeSlice
server property.Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the number of milliseconds that each client connection will
actively use in the Network Server before yielding to
another connection (
derby.drda.timeSlice
) - See Also:
getDrdaMaxThreads()
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getDrdaTraceAll
boolean getDrdaTraceAll()
Whether server-side tracing is enabled for all client connections (sessions). Refers to the
derby.drda.traceAll
server property.Tracing may for example be useful when providing technical support information. The Network Server also supports tracing for individual connections (sessions), see the Derby Server and Administration Guide ("Controlling tracing by using the trace facility") for details.
When tracing is enabled, tracing information from each client connection will be written to a separate trace file.
Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- whether tracing for all client connections is enabled
(
derby.drda.traceAll
) - See Also:
getDrdaTraceDirectory()
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getDrdaTraceDirectory
String getDrdaTraceDirectory()
Indicates the location of tracing files on the server host, if server tracing has been enabled.
If the server setting
derby.drda.traceDirectory
is set, its value will be returned. Otherwise, the Network Server's default values will be taken into account when producing the result.Requires
SystemPermission("server", "control")
if a security manager is installed.- Returns:
- the potential location of tracing files on the server host
- See Also:
getDrdaTraceAll()
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getConnectionCount
int getConnectionCount()
Gets the total number of current connections (waiting or active) to the Network Server.
Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the number of current connections
- See Also:
getActiveConnectionCount()
,getWaitingConnectionCount()
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getActiveConnectionCount
int getActiveConnectionCount()
Gets the number of currently active connections. All connections are active if the DrdaMaxThreads attribute (
derby.drda.maxThreads
property) is 0.If DrdaMaxThreads is > 0 and DrdaTimeSlice is 0, connections remain active until they are closed. If there are more than DrdaMaxThreads connections, inactive connections will be waiting for some active connection to close. The connection request will return when the connection becomes active.
If DrdaMaxThreads is > 0 and DrdaTimeSlice > 0, connections will be alternating beetween active and waiting according to Derby's time slicing algorithm.
Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the number of active connections
- See Also:
getDrdaMaxThreads()
,getDrdaTimeSlice()
,getWaitingConnectionCount()
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getWaitingConnectionCount
int getWaitingConnectionCount()
Gets the number of currently waiting connections. This number will always be 0 if DrdaMaxThreads is 0. Otherwise, if the total number of connections is less than or equal to DrdaMaxThreads, then no connections are waiting.
Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the number of waiting connections
- See Also:
getActiveConnectionCount()
,getDrdaMaxThreads()
,getDrdaTimeSlice()
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getConnectionThreadPoolSize
int getConnectionThreadPoolSize()
Get the size of the connection thread pool. If DrdaMaxThreads (
derby.drda.maxThreads
) is set to a non-zero value, the size of the thread pool will not exceed this value.Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the size of the Network Server's connection thread pool
- See Also:
getDrdaMaxThreads()
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getAccumulatedConnectionCount
int getAccumulatedConnectionCount()
Gets the accumulated number of connections. This includes all active and waiting connections since the Network Server was started. This number will not decrease as long as the Network Server is running.
Require
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the accumulated number of connections made since server startup
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getBytesReceived
long getBytesReceived()
Gets the total number of bytes read by the server since it was started.
Require
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the total number of bytes received by the server
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getBytesSent
long getBytesSent()
Gets the total number of bytes written by the server since it was started.
Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the total number of bytes sent by the server
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getBytesReceivedPerSecond
int getBytesReceivedPerSecond()
Gets the number of bytes received per second by the Network Server. This number is calculated by taking into account the number of bytes received since the last calculation (or since MBean startup if it is the first time this attibute is being read).
The shortest interval measured is 1 second. This means that a new value will not be calculated unless there has been at least 1 second since the last calculation.
Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the number of bytes received per second
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getBytesSentPerSecond
int getBytesSentPerSecond()
Gets the number of bytes sent per second by the Network Server. This number is calculated by taking into account the number of bytes sent since the last calculation (or since MBean startup if it is the first time this attibute is being read).
The shortest interval measured is 1 second. This means that a new value will not be calculated unless there has been at least 1 second since the last calculation.
Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the number of bytes sent per millisecond
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getStartTime
long getStartTime()
Gets the start time of the network server. The time is reported as the number of milliseconds (ms) since Unix epoch (1970-01-01 00:00:00 UTC), and corresponds to the value of
java.lang.System#currentTimeMillis()
at the time the Network Server was started.Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the difference, measured in milliseconds, between the time the Network Server was started and Unix epoch (1970-01-01T00:00:00Z)
- See Also:
System.currentTimeMillis()
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getUptime
long getUptime()
Gets the time (in milliseconds) the Network Server has been running. In other words, the time passed since the server was started.
Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Returns:
- the difference, measured in milliseconds, between the current time and the time the Network Server was started
- See Also:
getStartTime()
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ping
void ping() throws Exception
Executes the network server's
ping
command. Returns without errors if the server was successfully pinged.Note that the
ping
command itself will be executed from the network server instance that is actually running the server, and that the result will be transferred via JMX to the JMX client invoking this operation. This means that this operation will test network server connectivity from the same host (machine) as the network server, as opposed to when theping
command (or method) ofNetworkServerControl
is executed from a remote machine.This operation requires the following permission to be granted to the network server code base if a Java security manager is installed in the server JVM:
permission java.net.SocketPermission "*", "connect,resolve";
The value
"*"
will allow connections from the network server to any host and any port, and may be replaced with a more specific value if so desired. The required value will depend on the value of the-h
(orderby.drda.host
) (host) and-p
(orderby.drda.portNumber
) (port) settings of the Network Server.Requires
SystemPermission("server", "monitor")
if a security manager is installed.- Throws:
Exception
- if the ping attempt fails (an indication that the network server is not running properly)- See Also:
NetworkServerControl.ping()
,SocketPermission
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