org.apache.derby.mbeans.drda
Interface NetworkServerMBean

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.

See Also:

NetworkServerControl, SystemPermission, org.apache.derby.mbeans

Method Summary

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.
java.lang.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 keepalive probes and attempt to clean up connections for disconnected clients (the value of the derby.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.
java.lang.String	getDrdaSecurityMechanism() The Derby security mechanism required by the Network Server for all client connections.
java.lang.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 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.
boolean	getDrdaTraceAll() Whether server-side tracing is enabled for all client connections (sessions).
java.lang.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's ping command.

Method Detail

getDrdaHost

java.lang.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)

getDrdaKeepAlive

boolean getDrdaKeepAlive()

Reports whether or not the Derby Network Server will send keepalive probes and attempt to clean up connections for disconnected clients (the value of the derby.drda.keepAlive property).

If true, a keepalive 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 keepalive probes.

Requires SystemPermission("server", "monitor") if a security manager is installed.

Returns:

whether or not the Derby Network Server will send keepalive probes and attempt to clean up connections for disconnected clients (derby.drda.keepAlive)

See Also:

derby.drda.keepAlive documentation

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)

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.

getDrdaSecurityMechanism

java.lang.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)

getDrdaSslMode

java.lang.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)

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)

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()

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()

getDrdaTraceDirectory

java.lang.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()

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()

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()

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()

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()

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

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

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

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

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

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()

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()

ping

void ping()
          throws java.lang.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 the ping command (or method) of NetworkServerControl 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 (or derby.drda.host) (host) and -p (or derby.drda.portNumber) (port) settings of the Network Server.

Requires SystemPermission("server", "monitor") if a security manager is installed.

Throws:

java.lang.Exception - if the ping attempt fails (an indication that the network server is not running properly)

See Also:

NetworkServerControl.ping(), SocketPermission