org.apache.knox.gateway.audit.log4j.correlation

Class Log4jCorrelationService

java.lang.Object

org.apache.knox.gateway.audit.log4j.correlation.Log4jCorrelationService

All Implemented Interfaces:

CorrelationService

public class Log4jCorrelationService
extends Object
implements CorrelationService

Field Summary

Fields

Modifier and Type	Field and Description
static String	MDC_CORRELATION_CONTEXT_KEY

Fields inherited from interface org.apache.knox.gateway.audit.api.CorrelationService

PROTOCOL_HEADER

Constructor Summary

Constructors

Constructor and Description
Log4jCorrelationService()

Method Summary

Modifier and Type	Method and Description
void	attachContext(CorrelationContext context) Sets the current attached correlation context.
CorrelationContext	attachExternalizedContext(byte[] externalizedContext) Attaches the externalized correlation context
CorrelationContext	createContext() Creates a new correlation context.
CorrelationContext	detachContext() Detaches the existing attached context if any.
byte[]	detachExternalizedContext() Detaches the existing attached correlation context and returns it in externalized form.
<T> T	execute(CorrelationContext context, Callable<T> callable) Executes the callable within the provided correlation context.
CorrelationContext	getContext() Returns the current attached correlation context if any.
byte[]	getExternalizedContext() Returns externalized correlation context without detaching it from execution scope.
CorrelationContext	readExternalizedContext(byte[] externalizedContext) Restores correlation context from externalized form.

Methods inherited from class java.lang.Object

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

Field Detail

MDC_CORRELATION_CONTEXT_KEY

public static final String MDC_CORRELATION_CONTEXT_KEY

See Also:

Constant Field Values

Constructor Detail

Log4jCorrelationService

public Log4jCorrelationService()

Method Detail

createContext

public CorrelationContext createContext()

Description copied from interface: CorrelationService

Creates a new correlation context. The context is attached and empty.

Specified by:

createContext in interface CorrelationService

Returns:

A new correlation context.

getContext

public CorrelationContext getContext()

Description copied from interface: CorrelationService

Returns the current attached correlation context if any.

Specified by:

getContext in interface CorrelationService

Returns:

The current attached correlation context. May be null.

attachContext

public void attachContext(CorrelationContext context)

Description copied from interface: CorrelationService

Sets the current attached correlation context. Will overwrite any existing attached context if any. Null contexts are ignored and any existing attached context will remain.

Specified by:

attachContext in interface CorrelationService

Parameters:

context - The correlation context to attach.

detachContext

public CorrelationContext detachContext()

Description copied from interface: CorrelationService

Detaches the existing attached context if any. This will typically be done so that the context can be persisted or attached to a different thread.

Specified by:

detachContext in interface CorrelationService

Returns:

The now detached correlation context. May be null.

execute

public <T> T execute(CorrelationContext context,
                     Callable<T> callable)
              throws Exception

Description copied from interface: CorrelationService

Executes the callable within the provided correlation context. The provided context is attached and detached around the invocation of the callable.

Specified by:

execute in interface CorrelationService

Type Parameters:

T - Type of callable

Parameters:

context - The correlation context to establish around the invocation of the callable. May not be null.

callable - The callable to invoke after establishing the correlation context. May not be null.

Returns:

The result of the callable's call method.

Throws:

Exception - Thrown if thrown by the callable's call method.

attachExternalizedContext

public CorrelationContext attachExternalizedContext(byte[] externalizedContext)

Description copied from interface: CorrelationService

Attaches the externalized correlation context

Specified by:

attachExternalizedContext in interface CorrelationService

Parameters:

externalizedContext - The externalized correlation context

Returns:

An attached instance of correlation context that was restored form externalized context

detachExternalizedContext

public byte[] detachExternalizedContext()

Description copied from interface: CorrelationService

Detaches the existing attached correlation context and returns it in externalized form.

Specified by:

detachExternalizedContext in interface CorrelationService

Returns:

The detached externalized context

readExternalizedContext

public CorrelationContext readExternalizedContext(byte[] externalizedContext)

Description copied from interface: CorrelationService

Restores correlation context from externalized form.

Specified by:

readExternalizedContext in interface CorrelationService

Parameters:

externalizedContext - The externalized correlation context. May not be null.

Returns:

the correlation context that is not attached yet

getExternalizedContext

public byte[] getExternalizedContext()

Description copied from interface: CorrelationService

Returns externalized correlation context without detaching it from execution scope.

Specified by:

getExternalizedContext in interface CorrelationService

Returns:

The externalized correlation context