org.apache.knox.gateway.audit.api

Interface CorrelationService

All Known Implementing Classes:

Log4jCorrelationService

public interface CorrelationService

Manipulates the correlations context associated with the current thread.

Field Summary

Fields

Modifier and Type	Field and Description
static String	PROTOCOL_HEADER The recommended protocol header name used to transmit the correlation context over the network.

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.

Field Detail

PROTOCOL_HEADER

static final String PROTOCOL_HEADER

The recommended protocol header name used to transmit the correlation context over the network.

See Also:

Constant Field Values

Method Detail

createContext

CorrelationContext createContext()

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

Returns:

A new correlation context.

getContext

CorrelationContext getContext()

Returns the current attached correlation context if any.

Returns:

The current attached correlation context. May be null.

attachContext

void attachContext(CorrelationContext context)

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.

Parameters:

context - The correlation context to attach.

detachContext

CorrelationContext detachContext()

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.

Returns:

The now detached correlation context. May be null.

execute

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

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

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

CorrelationContext attachExternalizedContext(byte[] externalizedContext)

Attaches the externalized correlation context

Parameters:

externalizedContext - The externalized correlation context

Returns:

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

detachExternalizedContext

byte[] detachExternalizedContext()

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

Returns:

The detached externalized context

readExternalizedContext

CorrelationContext readExternalizedContext(byte[] externalizedContext)

Restores correlation context from externalized form.

Parameters:

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

Returns:

the correlation context that is not attached yet

getExternalizedContext

byte[] getExternalizedContext()

Returns externalized correlation context without detaching it from execution scope.

Returns:

The externalized correlation context