CommonContext (Aeron Message Transport)

java.lang.Object
- io.aeron.CommonContext

All Implemented Interfaces:

Cloneable

Direct Known Subclasses:

Aeron.Context, MediaDriver.Context
```
public class CommonContext
extends Object
implements Cloneable
```
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.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`CommonContext.InferableBoolean` Condition to specify a triple state conditional of always override to be true, always override to be false, or infer value.

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`AERON_DIR_PROP_DEFAULT` The value of the top level Aeron directory unless overridden by `aeronDirectoryName(String)`
`static String`	`AERON_DIR_PROP_NAME` The top level Aeron directory used for communication between a Media Driver and client.
`static String`	`ALIAS_PARAM_NAME` Parameter name for channel URI param to indicate an alias for the given URI.
`static String`	`CHANNEL_RECEIVE_TIMESTAMP_OFFSET_PARAM_NAME` Parameter name of the offset for the channel receive timestamp to be inserted into the incoming message on a subscription.
`static String`	`CHANNEL_SEND_TIMESTAMP_OFFSET_PARAM_NAME` Parameter name of the offset for the channel send timestamp to be inserted into the outgoing message on a publication.
`static String`	`CONGESTION_CONTROL_PARAM_NAME` Parameter name for Subscription URI param to indicate the congestion control algorithm to be used.
`static String`	`DEBUG_TIMEOUT_PROP_NAME` Property name for the timeout to use in debug mode.
`static long`	`DEFAULT_DRIVER_TIMEOUT_MS` Default timeout in which the driver is expected to respond or heartbeat.
`static long`	`DRIVER_TIMEOUT_MS` Timeout in which the driver is expected to respond or heartbeat.
`static String`	`DRIVER_TIMEOUT_PROP_NAME` Property name for driver timeout after which the driver is considered inactive.
`static String`	`ENDPOINT_PARAM_NAME` The address and port used for a UDP channel.
`static String`	`EOS_PARAM_NAME` Parameter name for channel URI param to indicate if End of Stream (EOS) should be sent or not.
`static String`	`FALLBACK_LOGGER_PROP_NAME` Property name for a fallback `PrintStream` based logger when it is not possible to use the error logging callback.
`static String`	`FLOW_CONTROL_PARAM_NAME` Parameter name for Publication URI param to indicate the flow control strategy to be used.
`static String`	`GROUP_PARAM_NAME` Parameter name for channel URI param to indicate if a Subscription represents a group member or individual from the perspective of message reception.
`static String`	`GROUP_TAG_PARAM_NAME` Parameter name for Subscription URI param to indicate the receiver tag to be sent in SMs.
`static String`	`INITIAL_TERM_ID_PARAM_NAME` Initial term id to be used when creating an `ExclusivePublication`.
`static String`	`INTERFACE_PARAM_NAME` The network interface via which the socket will be routed.
`static String`	`IPC_CHANNEL` URI base used for IPC channels for `Publication`s and `Subscription`s
`static String`	`IPC_MEDIA` Media type used for IPC shared memory from `Publication` to `Subscription` channels.
`static String`	`LINGER_PARAM_NAME` Key for timeout a publication to linger after draining in nanoseconds.
`static String`	`MDC_CONTROL_MODE_DYNAMIC` Valid value for `MDC_CONTROL_MODE_PARAM_NAME` when dynamic control is desired.
`static String`	`MDC_CONTROL_MODE_MANUAL` Valid value for `MDC_CONTROL_MODE_PARAM_NAME` when manual control is desired.
`static String`	`MDC_CONTROL_MODE_PARAM_NAME` Key for the mode of control that such be used for multi-destination-cast semantics.
`static String`	`MDC_CONTROL_PARAM_NAME` The param for the control channel IP address and port for multi-destination-cast semantics.
`static String`	`MEDIA_RCV_TIMESTAMP_OFFSET_PARAM_NAME` Parameter name of the offset for the media receive timestamp to be inserted into the incoming message on a subscription.
`static String`	`MTU_LENGTH_PARAM_NAME` MTU length parameter name for using as a channel URI param.
`static int`	`NULL_SESSION_ID` Value to represent a sessionId that is not to be used.
`static String`	`RECEIVER_WINDOW_LENGTH_PARAM_NAME` Parameter name for the congestion control's initial receiver window length.
`static String`	`REJOIN_PARAM_NAME` Parameter name for Subscription URI param to indicate if Images that go unavailable should be allowed to rejoin after a short cooldown or not.
`static String`	`RELIABLE_STREAM_PARAM_NAME` Parameter name for channel URI param to indicate if a subscribed stream must be reliable or not.
`static String`	`RESERVED_OFFSET` Placeholder value to use in URIs to specify that a timestamp should be stored in the reserved value field.
`static String`	`SESSION_ID_PARAM_NAME` Key for the session id for a publication or restricted subscription.
`static String`	`SOCKET_RCVBUF_PARAM_NAME` Parameter name for the underlying OS socket receive buffer length.
`static String`	`SOCKET_SNDBUF_PARAM_NAME` Parameter name for the underlying OS socket send buffer length.
`static String`	`SPARSE_PARAM_NAME` Parameter name for channel URI param to indicate if term buffers should be sparse.
`static String`	`SPIES_SIMULATE_CONNECTION_PARAM_NAME` Parameter name for Publication URI param to indicate whether spy subscriptions should simulate a connection.
`static String`	`SPY_PREFIX` URI used for Spy `Subscription`s whereby an outgoing unicast or multicast publication can be spied on by IPC without receiving it again via the network.
`static String`	`TAG_PREFIX` Qualifier for a value which is a tag for reference.
`static String`	`TAGS_PARAM_NAME` Key for the tags for a channel
`static String`	`TERM_ID_PARAM_NAME` Current term id to be used when creating an `ExclusivePublication`.
`static String`	`TERM_LENGTH_PARAM_NAME` The param name to be used for the term length as a channel URI param.
`static String`	`TERM_OFFSET_PARAM_NAME` Current term offset to be used when creating an `ExclusivePublication`.
`static String`	`TETHER_PARAM_NAME` Parameter name for channel URI param to indicate if a subscription should tether for local flow control.
`static String`	`TTL_PARAM_NAME` Time To Live param for a multicast datagram.
`static String`	`UDP_CHANNEL` URI base used for UDP channels for `Publication`s and `Subscription`s
`static String`	`UDP_MEDIA` Media type used for UDP sockets from `Publication` to `Subscription` channels.

Constructor Summary

Constructors
Constructor and Description

CommonContext()

Constructors
Constructor and Description
`CommonContext()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`File`	`aeronDirectory()` Get the directory in which the aeron config files are stored.
`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(String dirName)` Set the top level Aeron directory used for communication between the client and Media Driver, and the location of the data buffers.
`static long`	`checkDebugTimeout(long timeout, TimeUnit timeUnit)` Override the supplied timeout with the debug value if it has been set, and we are in debug mode.
`CommonContext`	`clone()` Perform a shallow copy of the object.
`void`	`close()` Release resources used by the CommonContext.
`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.
`UnsafeBuffer`	`countersMetaDataBuffer()` Get the buffer containing the counter metadata.
`CommonContext`	`countersMetaDataBuffer(UnsafeBuffer countersMetaDataBuffer)` Set the buffer containing the counter metadata.
`UnsafeBuffer`	`countersValuesBuffer()` Get the buffer containing the counters.
`CommonContext`	`countersValuesBuffer(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 AtomicBuffer`	`errorLogBuffer(ByteBuffer cncByteBuffer)` Get an `AtomicBuffer` which wraps the error log in the CnC file.
`static PrintStream`	`fallbackLogger()` Get the current fallback logger based on the supplied property.
`static String`	`generateRandomDirName()` Convert the default Aeron directory name to be a random name for use with embedded drivers.
`static String`	`getAeronDirectoryName()` Get the default directory name to be used if `aeronDirectoryName(String)` is not set.
`boolean`	`isConcluded()` Has the context had the `conclude()` method called.
`static boolean`	`isDriverActive(File directory, long driverTimeoutMs, Consumer<String> logger)` Is a media driver active in the given directory?
`boolean`	`isDriverActive(long driverTimeoutMs, Consumer<String> logger)` Is a media driver active in the current Aeron directory?
`static boolean`	`isDriverActive(long driverTimeoutMs, Consumer<String> logger, ByteBuffer cncByteBuffer)` Is a media driver active in the current mapped CnC buffer? If the driver is starting then it will wait for up to the driverTimeoutMs by checking for the cncVersion being set.
`MappedByteBuffer`	`mapExistingCncFile(Consumer<String> logger)` Map the CnC file if it exists.
`static File`	`newCncFile(String aeronDirectoryName)` Create a new command and control file in the administration directory.
`static File`	`newDefaultCncFile()` Create a new command and control file in the administration directory.
`static int`	`printErrorLog(AtomicBuffer errorBuffer, PrintStream out)` Print the contents of an error log to a `PrintStream` in human-readable format.
`static boolean`	`requestDriverTermination(File directory, DirectBuffer tokenBuffer, int tokenOffset, int tokenLength)` Request a driver to run its termination hook.
`int`	`saveErrorLog(PrintStream out)` Read the error log to a given `PrintStream`
`int`	`saveErrorLog(PrintStream out, ByteBuffer cncByteBuffer)` Read the error log to a given `PrintStream`
`static void`	`saveExistingErrors(File markFile, AtomicBuffer errorBuffer, PrintStream logger, String errorFilePrefix)` Save the existing errors from a `MarkFile` to a file in the same directory as the original `MarkFile` and optionally print location of such file to the supplied `PrintStream`.
`static ErrorHandler`	`setupErrorHandler(ErrorHandler userErrorHandler, DistinctErrorLog errorLog)` Wrap a user ErrorHandler so that error will continue to write to the errorLog.

Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - DRIVER_TIMEOUT_PROP_NAME
```
public static final String DRIVER_TIMEOUT_PROP_NAME
```
    Property name for driver timeout after which the driver is considered inactive.
    
    See Also:
    
    Constant Field Values
  - DEBUG_TIMEOUT_PROP_NAME
```
public static final String DEBUG_TIMEOUT_PROP_NAME
```
    Property name for the timeout to use in debug mode. By default, this is not set and the configured timeouts will be used. Setting this value adjusts timeouts to make debugging easier.
    
    See Also:
    
    Constant Field Values
  - DEFAULT_DRIVER_TIMEOUT_MS
```
public static final long DEFAULT_DRIVER_TIMEOUT_MS
```
    Default timeout in which the driver is expected to respond or heartbeat.
    
    See Also:
    
    Constant Field Values
  - DRIVER_TIMEOUT_MS
```
public static final long DRIVER_TIMEOUT_MS
```
    Timeout in which the driver is expected to respond or heartbeat.
  - NULL_SESSION_ID
```
public static final int NULL_SESSION_ID
```
    Value to represent a sessionId that is not to be used.
    
    See Also:
    
    Constant Field Values
  - AERON_DIR_PROP_NAME
```
public static final 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 String AERON_DIR_PROP_DEFAULT
```
    The value of the top level Aeron directory unless overridden by aeronDirectoryName(String)
  - IPC_MEDIA
```
public static final String IPC_MEDIA
```
    Media type used for IPC shared memory from Publication to Subscription channels.
    
    See Also:
    
    Constant Field Values
  - UDP_MEDIA
```
public static final String UDP_MEDIA
```
    Media type used for UDP sockets from Publication to Subscription channels.
    
    See Also:
    
    Constant Field Values
  - IPC_CHANNEL
```
public static final String IPC_CHANNEL
```
    URI base used for IPC channels for Publications and Subscriptions
    
    See Also:
    
    Constant Field Values
  - UDP_CHANNEL
```
public static final String UDP_CHANNEL
```
    URI base used for UDP channels for Publications and Subscriptions
    
    See Also:
    
    Constant Field Values
  - SPY_PREFIX
```
public static final 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
  - ENDPOINT_PARAM_NAME
```
public static final String ENDPOINT_PARAM_NAME
```
    The address and port used for a UDP channel. For the publisher it is the socket to send to, for the subscriber it is the socket to receive from.
    
    See Also:
    
    Constant Field Values
  - INTERFACE_PARAM_NAME
```
public static final String INTERFACE_PARAM_NAME
```
    The network interface via which the socket will be routed.
    
    See Also:
    
    Constant Field Values
  - INITIAL_TERM_ID_PARAM_NAME
```
public static final 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 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 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 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_PARAM_NAME
```
public static final String MTU_LENGTH_PARAM_NAME
```
    MTU length parameter name for using as a channel URI param. If this is greater than the network MTU for UDP then the packet will be fragmented and can amplify the impact of loss.
    
    See Also:
    
    Constant Field Values
  - TTL_PARAM_NAME
```
public static final String TTL_PARAM_NAME
```
    Time To Live param for a multicast datagram.
    
    See Also:
    
    Constant Field Values
  - MDC_CONTROL_PARAM_NAME
```
public static final String MDC_CONTROL_PARAM_NAME
```
    The param for the control channel IP address and port for multi-destination-cast semantics.
    
    See Also:
    
    Constant Field Values
  - MDC_CONTROL_MODE_PARAM_NAME
```
public static final String MDC_CONTROL_MODE_PARAM_NAME
```
    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 String MDC_CONTROL_MODE_MANUAL
```
    Valid value for MDC_CONTROL_MODE_PARAM_NAME when manual control is desired.
    
    See Also:
    
    Constant Field Values
  - MDC_CONTROL_MODE_DYNAMIC
```
public static final String MDC_CONTROL_MODE_DYNAMIC
```
    Valid value for MDC_CONTROL_MODE_PARAM_NAME when dynamic control is desired. Default value.
    
    See Also:
    
    Constant Field Values
  - SESSION_ID_PARAM_NAME
```
public static final String SESSION_ID_PARAM_NAME
```
    Key for the session id for a publication or restricted subscription.
    
    See Also:
    
    Constant Field Values
  - LINGER_PARAM_NAME
```
public static final String LINGER_PARAM_NAME
```
    Key for timeout a publication to linger after draining in nanoseconds.
    
    See Also:
    
    Constant Field Values
  - RELIABLE_STREAM_PARAM_NAME
```
public static final String RELIABLE_STREAM_PARAM_NAME
```
    Parameter name for channel URI param to indicate if a subscribed stream must be reliable or not. Value is boolean with true to recover loss and false to gap fill.
    
    See Also:
    
    Constant Field Values
  - TAGS_PARAM_NAME
```
public static final String TAGS_PARAM_NAME
```
    Key for the tags for a channel
    
    See Also:
    
    Constant Field Values
  - TAG_PREFIX
```
public static final String TAG_PREFIX
```
    Qualifier for a value which is a tag for reference. This prefix is use in the param value.
    
    See Also:
    
    Constant Field Values
  - SPARSE_PARAM_NAME
```
public static final String SPARSE_PARAM_NAME
```
    Parameter name for channel URI param to indicate if term buffers should be sparse. Value is boolean.
    
    See Also:
    
    Constant Field Values
  - ALIAS_PARAM_NAME
```
public static final String ALIAS_PARAM_NAME
```
    Parameter name for channel URI param to indicate an alias for the given URI. Value not interpreted by Aeron.
    This is a reserved application level param used to identify a particular channel for application purposes.
    
    See Also:
    
    Constant Field Values
  - EOS_PARAM_NAME
```
public static final String EOS_PARAM_NAME
```
    Parameter name for channel URI param to indicate if End of Stream (EOS) should be sent or not. Value is boolean.
    
    See Also:
    
    Constant Field Values
  - TETHER_PARAM_NAME
```
public static final String TETHER_PARAM_NAME
```
    Parameter name for channel URI param to indicate if a subscription should tether for local flow control. Value is boolean. A tether only applies when there is more than one matching active subscription. If tether is true then that subscription is included in flow control. If only one subscription then it tethers pace.
    
    See Also:
    
    Constant Field Values
  - GROUP_PARAM_NAME
```
public static final String GROUP_PARAM_NAME
```
    Parameter name for channel URI param to indicate if a Subscription represents a group member or individual from the perspective of message reception. This can inform loss handling and similar semantics.
    When configuring a subscription for an MDC publication then should be added as this is effective multicast.
    
    See Also:
    
    MDC_CONTROL_MODE_PARAM_NAME, MDC_CONTROL_PARAM_NAME, Constant Field Values
  - REJOIN_PARAM_NAME
```
public static final String REJOIN_PARAM_NAME
```
    Parameter name for Subscription URI param to indicate if Images that go unavailable should be allowed to rejoin after a short cooldown or not.
    
    See Also:
    
    Constant Field Values
  - CONGESTION_CONTROL_PARAM_NAME
```
public static final String CONGESTION_CONTROL_PARAM_NAME
```
    Parameter name for Subscription URI param to indicate the congestion control algorithm to be used. Options include static and cubic.
    
    See Also:
    
    Constant Field Values
  - FLOW_CONTROL_PARAM_NAME
```
public static final String FLOW_CONTROL_PARAM_NAME
```
    Parameter name for Publication URI param to indicate the flow control strategy to be used. Options include min, max, and pref.
    
    See Also:
    
    Constant Field Values
  - GROUP_TAG_PARAM_NAME
```
public static final String GROUP_TAG_PARAM_NAME
```
    Parameter name for Subscription URI param to indicate the receiver tag to be sent in SMs.
    
    See Also:
    
    Constant Field Values
  - SPIES_SIMULATE_CONNECTION_PARAM_NAME
```
public static final String SPIES_SIMULATE_CONNECTION_PARAM_NAME
```
    Parameter name for Publication URI param to indicate whether spy subscriptions should simulate a connection.
    
    See Also:
    
    Constant Field Values
  - SOCKET_SNDBUF_PARAM_NAME
```
public static final String SOCKET_SNDBUF_PARAM_NAME
```
    Parameter name for the underlying OS socket send buffer length.
    
    See Also:
    
    Constant Field Values
  - SOCKET_RCVBUF_PARAM_NAME
```
public static final String SOCKET_RCVBUF_PARAM_NAME
```
    Parameter name for the underlying OS socket receive buffer length.
    
    See Also:
    
    Constant Field Values
  - RECEIVER_WINDOW_LENGTH_PARAM_NAME
```
public static final String RECEIVER_WINDOW_LENGTH_PARAM_NAME
```
    Parameter name for the congestion control's initial receiver window length.
    
    See Also:
    
    Constant Field Values
  - MEDIA_RCV_TIMESTAMP_OFFSET_PARAM_NAME
```
public static final String MEDIA_RCV_TIMESTAMP_OFFSET_PARAM_NAME
```
    Parameter name of the offset for the media receive timestamp to be inserted into the incoming message on a subscription. The special value of 'reserved' can be used to insert into the reserved value field. Media receive timestamp is taken as the earliest possible point after the packet is received from the network. This is only supported in the C media driver, the Java Media Driver will generate an error if used.
    
    See Also:
    
    Constant Field Values
  - CHANNEL_RECEIVE_TIMESTAMP_OFFSET_PARAM_NAME
```
public static final String CHANNEL_RECEIVE_TIMESTAMP_OFFSET_PARAM_NAME
```
    Parameter name of the offset for the channel receive timestamp to be inserted into the incoming message on a subscription. The special value of 'reserved' can be used to insert into the reserved value field. Channel receive timestamp is taken as soon a possible after the packet is received by Aeron receiver from the transport bindings.
    
    See Also:
    
    Constant Field Values
  - CHANNEL_SEND_TIMESTAMP_OFFSET_PARAM_NAME
```
public static final String CHANNEL_SEND_TIMESTAMP_OFFSET_PARAM_NAME
```
    Parameter name of the offset for the channel send timestamp to be inserted into the outgoing message on a publication. The special value of 'reserved' can be used to insert into the reserved value field. Channel send timestamp is taken shortly before passing the message over to the configured transport bindings.
    
    See Also:
    
    Constant Field Values
  - RESERVED_OFFSET
```
public static final String RESERVED_OFFSET
```
    Placeholder value to use in URIs to specify that a timestamp should be stored in the reserved value field.
    
    See Also:
    
    Constant Field Values
  - FALLBACK_LOGGER_PROP_NAME
```
public static final String FALLBACK_LOGGER_PROP_NAME
```
    Property name for a fallback PrintStream based logger when it is not possible to use the error logging callback. Supported values are stdout, stderr, no_op (stderr is the default).
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - CommonContext
```
public CommonContext()
```
- Method Detail
  - fallbackLogger
```
public static PrintStream fallbackLogger()
```
    Get the current fallback logger based on the supplied property.
    
    Returns:
    
    the configured PrintStream.
  - clone
```
public CommonContext clone()
```
    Perform a shallow copy of the object.
    
    Overrides:
    
    clone in class Object
    
    Returns:
    
    a shallow copy of the object.
  - getAeronDirectoryName
```
public static String getAeronDirectoryName()
```
    Get the default directory name to be used if aeronDirectoryName(String) is not set. This will take the AERON_DIR_PROP_NAME if set and if not then AERON_DIR_PROP_DEFAULT.
    
    Returns:
    
    the default directory name to be used if aeronDirectoryName(String) is not set.
  - generateRandomDirName
```
public static 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.
  - isConcluded
```
public boolean isConcluded()
```
    Has the context had the conclude() method called.
    
    Returns:
    
    true of the conclude() method has been called.
  - concludeAeronDirectory
```
public CommonContext concludeAeronDirectory()
```
    Conclude the aeronDirectory() so it does not need to keep being recreated.
    
    Returns:
    
    this for a fluent API.
  - aeronDirectoryName
```
public 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 File aeronDirectory()
```
    Get the directory in which the aeron config files are stored.
    This is valid after a call to conclude() or concludeAeronDirectory().
    
    Returns:
    
    the directory in which the aeron config files are stored.
    
    See Also:
    
    aeronDirectoryName()
  - aeronDirectoryName
```
public CommonContext aeronDirectoryName(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 for a fluent API.
  - newDefaultCncFile
```
public static File newDefaultCncFile()
```
    Create a new command and control file in the administration directory.
    
    Returns:
    
    The newly created File.
  - newCncFile
```
public static File newCncFile(String aeronDirectoryName)
```
    Create a new command and control file in the administration directory.
    
    Parameters:
    
    aeronDirectoryName - name of the aeronDirectory that containing the cnc file.
    
    Returns:
    
    The newly created File.
  - countersMetaDataBuffer
```
public UnsafeBuffer countersMetaDataBuffer()
```
    Get the buffer containing the counter metadata. These counters are R/W for the driver, read only for all other users.
    
    Returns:
    
    The buffer storing the counter metadata.
  - countersMetaDataBuffer
```
public CommonContext countersMetaDataBuffer(UnsafeBuffer countersMetaDataBuffer)
```
    Set the buffer containing the counter metadata. Testing/internal purposes only.
    
    Parameters:
    
    countersMetaDataBuffer - The new counter metadata buffer.
    
    Returns:
    
    this for a fluent API.
  - countersValuesBuffer
```
public UnsafeBuffer countersValuesBuffer()
```
    Get the buffer containing the counters. These counters are R/W for the driver, read only for all other users.
    
    Returns:
    
    The buffer storing the counters.
  - countersValuesBuffer
```
public CommonContext countersValuesBuffer(UnsafeBuffer countersValuesBuffer)
```
    Set the buffer containing the counters. Testing/internal purposes only.
    
    Parameters:
    
    countersValuesBuffer - The new counters buffer.
    
    Returns:
    
    this for a fluent API.
  - cncFile
```
public 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:
    
    this for a fluent API.
  - driverTimeoutMs
```
public long driverTimeoutMs()
```
    Get the driver timeout in milliseconds.
    
    Returns:
    
    driver timeout in milliseconds.
  - checkDebugTimeout
```
public static long checkDebugTimeout(long timeout,
                                     TimeUnit timeUnit)
```
    Override the supplied timeout with the debug value if it has been set, and we are in debug mode.
    
    Parameters:
    
    timeout - The timeout value currently in use.
    
    timeUnit - The units of the timeout value. Debug timeout is specified in ns, so will be converted to this unit.
    
    Returns:
    
    The debug timeout if specified, and we are being debugged or the supplied value if not. Will be in timeUnit units.
  - deleteAeronDirectory
```
public void deleteAeronDirectory()
```
    Delete the current Aeron directory, throwing errors if not possible.
  - mapExistingCncFile
```
public MappedByteBuffer mapExistingCncFile(Consumer<String> logger)
```
    Map the CnC file if it exists.
    
    Parameters:
    
    logger - for feedback
    
    Returns:
    
    a new mapping for the file if it exists otherwise null;
  - isDriverActive
```
public static boolean isDriverActive(File directory,
                                     long driverTimeoutMs,
                                     Consumer<String> logger)
```
    Is a media driver active in the given directory?
    
    Parameters:
    
    directory - to check
    
    driverTimeoutMs - for the driver liveness check.
    
    logger - for feedback as liveness checked.
    
    Returns:
    
    true if a driver is active or false if not.
  - isDriverActive
```
public boolean isDriverActive(long driverTimeoutMs,
                              Consumer<String> logger)
```
    Is a media driver active in the current Aeron directory?
    
    Parameters:
    
    driverTimeoutMs - for the driver liveness check.
    
    logger - for feedback as liveness checked.
    
    Returns:
    
    true if a driver is active or false if not.
  - isDriverActive
```
public static boolean isDriverActive(long driverTimeoutMs,
                                     Consumer<String> logger,
                                     ByteBuffer cncByteBuffer)
```
    Is a media driver active in the current mapped CnC buffer? If the driver is starting then it will wait for up to the driverTimeoutMs by checking for the cncVersion being set.
    
    Parameters:
    
    driverTimeoutMs - for the driver liveness check.
    
    logger - for feedback as liveness checked.
    
    cncByteBuffer - for the existing CnC file.
    
    Returns:
    
    true if a driver is active or false if not.
  - requestDriverTermination
```
public static boolean requestDriverTermination(File directory,
                                               DirectBuffer tokenBuffer,
                                               int tokenOffset,
                                               int tokenLength)
```
    Request a driver to run its termination hook.
    
    Parameters:
    
    directory - for the driver.
    
    tokenBuffer - containing the optional token for the request.
    
    tokenOffset - within the tokenBuffer at which the token begins.
    
    tokenLength - of the token in the tokenBuffer.
    
    Returns:
    
    true if request was sent or false if request could not be sent.
  - saveErrorLog
```
public int saveErrorLog(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(PrintStream out,
                        ByteBuffer 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.
  - printErrorLog
```
public static int printErrorLog(AtomicBuffer errorBuffer,
                                PrintStream out)
```
    Print the contents of an error log to a PrintStream in human-readable format.
    
    Parameters:
    
    errorBuffer - to read errors from.
    
    out - print the errors to.
    
    Returns:
    
    number of distinct errors observed.
  - saveExistingErrors
```
public static void saveExistingErrors(File markFile,
                                      AtomicBuffer errorBuffer,
                                      PrintStream logger,
                                      String errorFilePrefix)
```
    Save the existing errors from a MarkFile to a file in the same directory as the original MarkFile and optionally print location of such file to the supplied PrintStream.
    
    Parameters:
    
    markFile - which contains the error buffer.
    
    errorBuffer - which wraps the error log.
    
    logger - to which the existing errors will be printed.
    
    errorFilePrefix - to add to the generated error file.
  - errorLogBuffer
```
public static AtomicBuffer errorLogBuffer(ByteBuffer cncByteBuffer)
```
    Get an AtomicBuffer which wraps the error log in the CnC file.
    
    Parameters:
    
    cncByteBuffer - which contains the error log.
    
    Returns:
    
    an AtomicBuffer which wraps the error log in the CnC file.
  - setupErrorHandler
```
public static ErrorHandler setupErrorHandler(ErrorHandler userErrorHandler,
                                             DistinctErrorLog errorLog)
```
    Wrap a user ErrorHandler so that error will continue to write to the errorLog.
    
    Parameters:
    
    userErrorHandler - the user specified ErrorHandler, can be null.
    
    errorLog - the configured errorLog, either the default or user supplied.
    
    Returns:
    
    an error handler that will delegate to both the userErrorHandler and the errorLog.

Class CommonContext

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DRIVER_TIMEOUT_PROP_NAME

DEBUG_TIMEOUT_PROP_NAME

DEFAULT_DRIVER_TIMEOUT_MS

DRIVER_TIMEOUT_MS

NULL_SESSION_ID

AERON_DIR_PROP_NAME

AERON_DIR_PROP_DEFAULT

IPC_MEDIA

UDP_MEDIA

IPC_CHANNEL

UDP_CHANNEL

SPY_PREFIX

ENDPOINT_PARAM_NAME

INTERFACE_PARAM_NAME

INITIAL_TERM_ID_PARAM_NAME

TERM_ID_PARAM_NAME

TERM_OFFSET_PARAM_NAME

TERM_LENGTH_PARAM_NAME

MTU_LENGTH_PARAM_NAME

TTL_PARAM_NAME

MDC_CONTROL_PARAM_NAME

MDC_CONTROL_MODE_PARAM_NAME

MDC_CONTROL_MODE_MANUAL

MDC_CONTROL_MODE_DYNAMIC

SESSION_ID_PARAM_NAME

LINGER_PARAM_NAME

RELIABLE_STREAM_PARAM_NAME

TAGS_PARAM_NAME

TAG_PREFIX

SPARSE_PARAM_NAME

ALIAS_PARAM_NAME

EOS_PARAM_NAME

TETHER_PARAM_NAME

GROUP_PARAM_NAME

REJOIN_PARAM_NAME

CONGESTION_CONTROL_PARAM_NAME

FLOW_CONTROL_PARAM_NAME

GROUP_TAG_PARAM_NAME

SPIES_SIMULATE_CONNECTION_PARAM_NAME

SOCKET_SNDBUF_PARAM_NAME

SOCKET_RCVBUF_PARAM_NAME

RECEIVER_WINDOW_LENGTH_PARAM_NAME

MEDIA_RCV_TIMESTAMP_OFFSET_PARAM_NAME

CHANNEL_RECEIVE_TIMESTAMP_OFFSET_PARAM_NAME

CHANNEL_SEND_TIMESTAMP_OFFSET_PARAM_NAME

RESERVED_OFFSET

FALLBACK_LOGGER_PROP_NAME

Constructor Detail

CommonContext

Method Detail

fallbackLogger

clone

getAeronDirectoryName

generateRandomDirName

conclude

isConcluded

concludeAeronDirectory

aeronDirectoryName

aeronDirectory

aeronDirectoryName

newDefaultCncFile

newCncFile

countersMetaDataBuffer

countersMetaDataBuffer

countersValuesBuffer

countersValuesBuffer

cncFile

driverTimeoutMs

driverTimeoutMs

checkDebugTimeout

deleteAeronDirectory

mapExistingCncFile

isDriverActive