io.aeron

Class CommonContext

java.lang.Object

io.aeron.CommonContext

All Implemented Interfaces:

java.lang.AutoCloseable

Direct Known Subclasses:

Aeron.Context

public class CommonContext
extends java.lang.Object
implements java.lang.AutoCloseable

This class provides the Media Driver and client with common configuration for the Aeron directory. This class should have conclude() called before the methods are used or at least concludeAeronDirectory() to avoid NPEs. Properties

• aeron.dir: Use value as directory name for Aeron buffers and status.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	AERON_DIR_PROP_DEFAULT The value of the top level Aeron directory unless overridden by aeronDirectoryName(String)
static java.lang.String	AERON_DIR_PROP_NAME The top level Aeron directory used for communication between a Media Driver and client.
static long	DEFAULT_DRIVER_TIMEOUT_MS Timeout in which the driver is expected to respond.
static java.lang.String	INITIAL_TERM_ID_PARAM_NAME Initial term id to be used when creating an ExclusivePublication.
static java.lang.String	IPC_CHANNEL URI used for IPC Publications and Subscriptions
static java.lang.String	MDC_CONTROL_MODE Key for the mode of control that such be used for multi-destination-cast semantics.
static java.lang.String	MDC_CONTROL_MODE_MANUAL Valid value for MDC_CONTROL_MODE when manual control is desired.
static java.lang.String	MTU_LENGTH_URI_PARAM_NAME MTU length parameter name for using as a channel URI param.
static java.lang.String	RELIABLE_STREAM_PARAM_NAME Parameter name for channel URI param to indicate if a subscribed must be reliable or not.
static java.lang.String	SPY_PREFIX URI used for Spy Subscriptions whereby an outgoing unicast or multicast publication can be spied on by IPC without receiving it again via the network.
static java.lang.String	TERM_ID_PARAM_NAME Current term id to be used when creating an ExclusivePublication.
static java.lang.String	TERM_LENGTH_PARAM_NAME The param name to be used for the term length as a channel URI param.
static java.lang.String	TERM_OFFSET_PARAM_NAME Current term offset to be used when creating an ExclusivePublication.

Constructor Summary

Constructors

Constructor and Description
CommonContext() Create a new context with Aeron directory and delete on exit values based on the current system properties.

Method Summary

Modifier and Type	Method and Description
java.io.File	aeronDirectory() Get the directory in which the aeron config files are stored.
java.lang.String	aeronDirectoryName() Get the top level Aeron directory used for communication between the client and Media Driver, and the location of the data buffers.
CommonContext	aeronDirectoryName(java.lang.String dirName) Set the top level Aeron directory used for communication between the client and Media Driver, and the location of the data buffers.
void	close() Release resources used by the CommonContext.
java.io.File	cncFile() Get the command and control file.
CommonContext	conclude() This completes initialization of the CommonContext object.
CommonContext	concludeAeronDirectory() Conclude the aeronDirectory() so it does not need to keep being recreated.
org.agrona.concurrent.UnsafeBuffer	countersMetaDataBuffer() Get the buffer containing the counter meta data.
CommonContext	countersMetaDataBuffer(org.agrona.concurrent.UnsafeBuffer countersMetaDataBuffer) Set the buffer containing the counter meta data.
org.agrona.concurrent.UnsafeBuffer	countersValuesBuffer() Get the buffer containing the counters.
CommonContext	countersValuesBuffer(org.agrona.concurrent.UnsafeBuffer countersValuesBuffer) Set the buffer containing the counters
void	deleteAeronDirectory() Delete the current Aeron directory, throwing errors if not possible.
long	driverTimeoutMs() Get the driver timeout in milliseconds.
CommonContext	driverTimeoutMs(long driverTimeoutMs) Set the driver timeout in milliseconds
static java.lang.String	generateRandomDirName() Convert the default Aeron directory name to be a random name for use with embedded drivers.
static boolean	isDriverActive(java.io.File directory, long driverTimeoutMs, java.util.function.Consumer<java.lang.String> logProgress) Is a media driver active in the given directory?
boolean	isDriverActive(long driverTimeoutMs, java.util.function.Consumer<java.lang.String> logHandler) Is a media driver active in the current Aeron directory?
static boolean	isDriverActive(long driverTimeoutMs, java.util.function.Consumer<java.lang.String> logProgress, java.nio.MappedByteBuffer cncByteBuffer) Is a media driver active in the current mapped CnC buffer?
java.nio.MappedByteBuffer	mapExistingCncFile(java.util.function.Consumer<java.lang.String> logProgress) Map the CnC file if it exists.
static java.io.File	newDefaultCncFile() Create a new command and control file in the administration directory.
int	saveErrorLog(java.io.PrintStream out) Read the error log to a given PrintStream
int	saveErrorLog(java.io.PrintStream out, java.nio.MappedByteBuffer cncByteBuffer) Read the error log to a given PrintStream

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

AERON_DIR_PROP_NAME

public static final java.lang.String AERON_DIR_PROP_NAME

The top level Aeron directory used for communication between a Media Driver and client.

See Also:

Constant Field Values

AERON_DIR_PROP_DEFAULT

public static final java.lang.String AERON_DIR_PROP_DEFAULT

The value of the top level Aeron directory unless overridden by aeronDirectoryName(String)

IPC_CHANNEL

public static final java.lang.String IPC_CHANNEL

URI used for IPC Publications and Subscriptions

See Also:

Constant Field Values

SPY_PREFIX

public static final java.lang.String SPY_PREFIX

URI used for Spy Subscriptions whereby an outgoing unicast or multicast publication can be spied on by IPC without receiving it again via the network.

See Also:

Constant Field Values

DEFAULT_DRIVER_TIMEOUT_MS

public static final long DEFAULT_DRIVER_TIMEOUT_MS

Timeout in which the driver is expected to respond.

See Also:

Constant Field Values

INITIAL_TERM_ID_PARAM_NAME

public static final java.lang.String INITIAL_TERM_ID_PARAM_NAME

Initial term id to be used when creating an ExclusivePublication.

See Also:

Constant Field Values

TERM_ID_PARAM_NAME

public static final java.lang.String TERM_ID_PARAM_NAME

Current term id to be used when creating an ExclusivePublication.

See Also:

Constant Field Values

TERM_OFFSET_PARAM_NAME

public static final java.lang.String TERM_OFFSET_PARAM_NAME

Current term offset to be used when creating an ExclusivePublication.

See Also:

Constant Field Values

TERM_LENGTH_PARAM_NAME

public static final java.lang.String TERM_LENGTH_PARAM_NAME

The param name to be used for the term length as a channel URI param.

See Also:

Constant Field Values

MTU_LENGTH_URI_PARAM_NAME

public static final java.lang.String MTU_LENGTH_URI_PARAM_NAME

MTU length parameter name for using as a channel URI param.

See Also:

Constant Field Values

MDC_CONTROL_MODE

public static final java.lang.String MDC_CONTROL_MODE

Key for the mode of control that such be used for multi-destination-cast semantics.

See Also:

Constant Field Values

MDC_CONTROL_MODE_MANUAL

public static final java.lang.String MDC_CONTROL_MODE_MANUAL

Valid value for MDC_CONTROL_MODE when manual control is desired.

See Also:

Constant Field Values

RELIABLE_STREAM_PARAM_NAME

public static final java.lang.String RELIABLE_STREAM_PARAM_NAME

Parameter name for channel URI param to indicate if a subscribed must be reliable or not. Value is boolean.

See Also:

Constant Field Values

Constructor Detail

CommonContext

public CommonContext()

Create a new context with Aeron directory and delete on exit values based on the current system properties.

Method Detail

generateRandomDirName

public static java.lang.String generateRandomDirName()

Convert the default Aeron directory name to be a random name for use with embedded drivers.

Returns:

random directory name with default directory name as base

conclude

public CommonContext conclude()

This completes initialization of the CommonContext object. It is automatically called by subclasses.

Returns:

this Object for method chaining.

concludeAeronDirectory

public CommonContext concludeAeronDirectory()

Conclude the aeronDirectory() so it does not need to keep being recreated.

Returns:

this for a fluent API.

aeronDirectoryName

public java.lang.String aeronDirectoryName()

Get the top level Aeron directory used for communication between the client and Media Driver, and the location of the data buffers.

Returns:

The top level Aeron directory.

aeronDirectory

public java.io.File aeronDirectory()

Get the directory in which the aeron config files are stored. This is valid after a call to conclude().

Returns:

the directory in which the aeron config files are stored.

See Also:

aeronDirectoryName()

aeronDirectoryName

public CommonContext aeronDirectoryName(java.lang.String dirName)

Set the top level Aeron directory used for communication between the client and Media Driver, and the location of the data buffers.

Parameters:

dirName - New top level Aeron directory.

Returns:

this Object for method chaining.

newDefaultCncFile

public static java.io.File newDefaultCncFile()

Create a new command and control file in the administration directory.

Returns:

The newly created File.

countersMetaDataBuffer

public org.agrona.concurrent.UnsafeBuffer countersMetaDataBuffer()

Get the buffer containing the counter meta data.

Returns:

The buffer storing the counter meta data.

countersMetaDataBuffer

public CommonContext countersMetaDataBuffer(org.agrona.concurrent.UnsafeBuffer countersMetaDataBuffer)

Set the buffer containing the counter meta data.

Parameters:

countersMetaDataBuffer - The new counter meta data buffer.

Returns:

this Object for method chaining.

countersValuesBuffer

public org.agrona.concurrent.UnsafeBuffer countersValuesBuffer()

Get the buffer containing the counters.

Returns:

The buffer storing the counters.

countersValuesBuffer

public CommonContext countersValuesBuffer(org.agrona.concurrent.UnsafeBuffer countersValuesBuffer)

Set the buffer containing the counters

Parameters:

countersValuesBuffer - The new counters buffer.

Returns:

this Object for method chaining.

cncFile

public java.io.File cncFile()

Get the command and control file.

Returns:

The command and control file.

driverTimeoutMs

public CommonContext driverTimeoutMs(long driverTimeoutMs)

Set the driver timeout in milliseconds

Parameters:

driverTimeoutMs - to indicate liveness of driver

Returns:

driver timeout in milliseconds

driverTimeoutMs

public long driverTimeoutMs()

Get the driver timeout in milliseconds.

Returns:

driver timeout in milliseconds.

deleteAeronDirectory

public void deleteAeronDirectory()

Delete the current Aeron directory, throwing errors if not possible.

mapExistingCncFile

public java.nio.MappedByteBuffer mapExistingCncFile(java.util.function.Consumer<java.lang.String> logProgress)

Map the CnC file if it exists.

Parameters:

logProgress - for feedback

Returns:

a new mapping for the file if it exists otherwise null;

isDriverActive

public static boolean isDriverActive(java.io.File directory,
                                     long driverTimeoutMs,
                                     java.util.function.Consumer<java.lang.String> logProgress)

Is a media driver active in the given directory?

Parameters:

directory - to check

driverTimeoutMs - for the driver liveness check.

logProgress - for feedback as liveness checked.

Returns:

true if a driver is active or false if not.

isDriverActive

public boolean isDriverActive(long driverTimeoutMs,
                              java.util.function.Consumer<java.lang.String> logHandler)

Is a media driver active in the current Aeron directory?

Parameters:

driverTimeoutMs - for the driver liveness check.

logHandler - for feedback as liveness checked.

Returns:

true if a driver is active or false if not.

isDriverActive

public static boolean isDriverActive(long driverTimeoutMs,
                                     java.util.function.Consumer<java.lang.String> logProgress,
                                     java.nio.MappedByteBuffer cncByteBuffer)

Is a media driver active in the current mapped CnC buffer?

Parameters:

driverTimeoutMs - for the driver liveness check.

logProgress - for feedback as liveness checked.

cncByteBuffer - for the existing CnC file.

Returns:

true if a driver is active or false if not.

saveErrorLog

public int saveErrorLog(java.io.PrintStream out)

Read the error log to a given PrintStream

Parameters:

out - to write the error log contents to.

Returns:

the number of observations from the error log.

saveErrorLog

public int saveErrorLog(java.io.PrintStream out,
                        java.nio.MappedByteBuffer cncByteBuffer)

Read the error log to a given PrintStream

Parameters:

out - to write the error log contents to.

cncByteBuffer - containing the error log.

Returns:

the number of observations from the error log.

close

public void close()

Release resources used by the CommonContext.

Specified by:

close in interface java.lang.AutoCloseable