Package org.bonitasoft.engine.mdc

Class MDCHelper

java.lang.Object

org.bonitasoft.engine.mdc.MDCHelper

public class MDCHelper
extends Object

Provides usefull methods for working with MDC.

Use the various tryWithMDC(java.util.function.Supplier<? extends org.bonitasoft.engine.mdc.AbstractMDC>, org.bonitasoft.engine.mdc.MDCHelper.CheckedCallable4<V, E1, E2, E3, E4>) methods to execute a runnable or a callable with MDC information in the context.
You may provide a context Supplier directly, or a key object for which a Supplier was previously registered with supplyMDC(java.util.function.Supplier<? extends org.bonitasoft.engine.mdc.AbstractMDC>, java.lang.Object) methods.

Use the appropriate Runnable or Callable implementation dependending on the number of Exception you want to throw.
When used with lambdas, lambda will take only the common exception superclass. So instead of writing

 Supplier<AbstractMDC> mdc = () -> new AbstractMDC(Map.of(key, value)) {};
 MDCHelper.tryWithMDC(mdc, ()->{
     // throws Exception1 or Exception2
     ...
 });
 

You should declare the type and write

 Supplier<AbstractMDC> mdc = () -> new AbstractMDC(Map.of(key, value)) {};
 CheckedRunnable2<Exception1, Exception2> run = ()->{
     // throws Exception1 or Exception2
     ...
 };
 MDCHelper.tryWithMDC(mdc, run);
 

When an exception is thrown within a tryWithMDC(java.util.function.Supplier<? extends org.bonitasoft.engine.mdc.AbstractMDC>, org.bonitasoft.engine.mdc.MDCHelper.CheckedCallable4<V, E1, E2, E3, E4>) method and not caught by the Runnable or Callable, the current context is registered with supplyMDC(java.util.function.Supplier<? extends org.bonitasoft.engine.mdc.AbstractMDC>, java.lang.Object) for the exception.
So calling tryWithMDC(Object, CheckedRunnable4) with the exception as usingObject key will allow you to log the exception with the original context.
You can even call this method when no context was supplied, as it would have no noticeable effect.

See Also:

• the base implementation for all MDC classes

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	MDCHelper.CheckedCallable<V,E extends Throwable>	Like Callable but throwing a checked exception
static interface	MDCHelper.CheckedCallable2<V,E1 extends Throwable,E2 extends Throwable>	Like Callable but throwing 2 checked exceptions
static interface	MDCHelper.CheckedCallable3<V,E1 extends Throwable,E2 extends Throwable,E3 extends Throwable>	Like Callable but throwing 3 checked exceptions
static interface	MDCHelper.CheckedCallable4<V,E1 extends Throwable,E2 extends Throwable,E3 extends Throwable,E4 extends Throwable>	Like Callable but throwing 4 checked exceptions
static interface	MDCHelper.CheckedRunnable<E extends Throwable>	Like Runnable but throwing a checked exception
static interface	MDCHelper.CheckedRunnable2<E1 extends Throwable,E2 extends Throwable>	Like Runnable but throwing 2 checked exceptions
static interface	MDCHelper.CheckedRunnable3<E1 extends Throwable,E2 extends Throwable,E3 extends Throwable>	Like Runnable but throwing 3 checked exceptions
static interface	MDCHelper.CheckedRunnable4<E1 extends Throwable,E2 extends Throwable,E3 extends Throwable,E4 extends Throwable>	Like Runnable but throwing 4 checked exceptions

Method Summary

Modifier and Type	Method	Description
static AbstractMDC	getMDC(Object usingObject)	Get an MDC, to encapsulate in a try with.
static Supplier<? extends AbstractMDC>	makeCurrentContextSupplier()	Make a supplier that will get the current context, to create a similar MDC in its time (usually in another thread)
static void	supplyMDC(Supplier<? extends AbstractMDC> mdcSupplier, Object usingObject)	Supply a MDC to an object that may use it later.
static void	supplyMDC(Supplier<? extends AbstractMDC> mdcSupplier, Object usingObject, boolean overwrite)	Supply a MDC to an object that may use it later.
static <V, E1 extends Throwable, E2 extends Throwable, E3 extends Throwable, E4 extends Throwable> V	tryWithMDC(Object usingObject, MDCHelper.CheckedCallable4<V,E1,E2,E3,E4> callable)	Try and invoke a callable with MDC
static <E1 extends Throwable, E2 extends Throwable, E3 extends Throwable, E4 extends Throwable> void	tryWithMDC(Object usingObject, MDCHelper.CheckedRunnable4<E1,E2,E3,E4> runnable)	Try and invoke a runnable with MDC
static <V, E1 extends Throwable, E2 extends Throwable, E3 extends Throwable, E4 extends Throwable> V	tryWithMDC(Supplier<? extends AbstractMDC> mdcSupplier, MDCHelper.CheckedCallable4<V,E1,E2,E3,E4> callable)	Try and invoke a callable with MDC
static <E1 extends Throwable, E2 extends Throwable, E3 extends Throwable, E4 extends Throwable> void	tryWithMDC(Supplier<? extends AbstractMDC> mdcSupplier, MDCHelper.CheckedRunnable4<E1,E2,E3,E4> runnable)	Try and invoke a runnable with MDC

Methods inherited from class java.lang.Object

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

Method Details

makeCurrentContextSupplier

public static Supplier<? extends AbstractMDC> makeCurrentContextSupplier()

Make a supplier that will get the current context, to create a similar MDC in its time (usually in another thread)

Returns:

MDC supplier holding information from current context in this thread

supplyMDC

public static void supplyMDC(Supplier<? extends AbstractMDC> mdcSupplier,
 Object usingObject)

Supply a MDC to an object that may use it later.

Parameters:

mdcSupplier - supplies a MDC

usingObject - the object that will need MDC

supplyMDC

public static void supplyMDC(Supplier<? extends AbstractMDC> mdcSupplier,
 Object usingObject,
 boolean overwrite)

Supply a MDC to an object that may use it later.

Parameters:

mdcSupplier - supplies a MDC

usingObject - the object that will need MDC

overwrite - whether to overwrite an existing supplier

getMDC

public static AbstractMDC getMDC(Object usingObject)

Get an MDC, to encapsulate in a try with.

Parameters:

usingObject - the object using the MDC, for which a supplier may have been provided

Returns:

the supplied MDC or null

tryWithMDC

public static <V,
E1 extends Throwable,
E2 extends Throwable,
E3 extends Throwable,
E4 extends Throwable>
V tryWithMDC(Supplier<? extends AbstractMDC> mdcSupplier,
 MDCHelper.CheckedCallable4<V,E1,E2,E3,E4> callable)
      throws E1,
E2,
E3,
E4

Try and invoke a callable with MDC

Type Parameters:

V - the result type

Parameters:

mdcSupplier - supplies a MDC

callable - the callable with result

Returns:

the callable result

Throws:

E - exception in callable

E1 extends Throwable

E2 extends Throwable

E3 extends Throwable

E4 extends Throwable

tryWithMDC

public static <V,
E1 extends Throwable,
E2 extends Throwable,
E3 extends Throwable,
E4 extends Throwable>
V tryWithMDC(Object usingObject,
 MDCHelper.CheckedCallable4<V,E1,E2,E3,E4> callable)
      throws E1,
E2,
E3,
E4

Try and invoke a callable with MDC

Type Parameters:

V - the result type

Parameters:

usingObject - the object using the MDC, for which a supplier may have been provided

callable - the callable with result

Returns:

the callable result

Throws:

E - exception in callable

E1 extends Throwable

E2 extends Throwable

E3 extends Throwable

E4 extends Throwable

tryWithMDC

public static <E1 extends Throwable,
E2 extends Throwable,
E3 extends Throwable,
E4 extends Throwable>
void tryWithMDC(Supplier<? extends AbstractMDC> mdcSupplier,
 MDCHelper.CheckedRunnable4<E1,E2,E3,E4> runnable)
         throws E1,
E2,
E3,
E4

Try and invoke a runnable with MDC

Parameters:

mdcSupplier - supplies a MDC

runnable - the runnable (without result)

Throws:

E - exception in runnable

E1 extends Throwable

E2 extends Throwable

E3 extends Throwable

E4 extends Throwable

tryWithMDC

public static <E1 extends Throwable,
E2 extends Throwable,
E3 extends Throwable,
E4 extends Throwable>
void tryWithMDC(Object usingObject,
 MDCHelper.CheckedRunnable4<E1,E2,E3,E4> runnable)
         throws E1,
E2,
E3,
E4

Try and invoke a runnable with MDC

Parameters:

usingObject - the object using the MDC, for which a supplier may have been provided

runnable - the runnable (without result)

Throws:

E - exception in runnable

E1 extends Throwable

E2 extends Throwable

E3 extends Throwable

E4 extends Throwable