[[quick]]
= AspectJ Quick Reference

[[quick-pointcuts]]
== Pointcuts

[cols=",",]
|===
|*Methods and Constructors* |

|`call(Signature)` |every call to any method or constructor matching
`Signature` at the call site

|`execution(Signature)` |every execution of any method or constructor
matching `Signature`

|*Fields* |

|`get(Signature)` |every reference to any field matching `Signature`

|`set(Signature)` |every assignment to any field matching `Signature`.
The assigned value can be exposed with an `args` pointcut

|*Exception Handlers* |

|`handler(TypePattern)` |every exception handler for any `Throwable`
type in `TypePattern`. The exception value can be exposed with an `args`
pointcut

|*Advice* |

|`adviceexecution()` |every execution of any piece of advice

|*Initialization* |

|`staticinitialization(TypePattern)` |every execution of a static
initializer for any type in `TypePattern`

|`initialization(Signature)` |every initialization of an object when the
first constructor called in the type matches `Signature`, encompassing
the return from the super constructor call to the return of the
first-called constructor

|`preinitialization(Signature)` |every pre-initialization of an object
when the first constructor called in the type matches `Signature`,
encompassing the entry of the first-called constructor to the call to
the super constructor

|*Lexical* |

|`within(TypePattern)` |every join point from code defined in a type in
`TypePattern`

|`withincode(Signature)` |every join point from code defined in a method
or constructor matching `Signature`
|===

[[quick-typePatterns]]
== Type Patterns

A type pattern is one of

[cols=",",]
|===
|*Type pattern* |

|`TypeNamePattern` |all types in `TypeNamePattern`

|`SubtypePattern` |all types in `SubtypePattern`, a pattern with a `+`

|`ArrayTypePattern` |all types in `ArrayTypePattern`, a pattern with one or more ``[]``s.

|`!TypePattern` |all types not in `TypePattern`

|`TypePattern0 && TypePattern1` |all types in both `TypePattern0` and `TypePattern1`

|`TypePattern0 \|\| TypePattern1` |all types in either `TypePattern0` or `TypePattern1`

|`( TypePattern )` |all types in `TypePattern`
|===

where `TypeNamePattern` can either be a plain type name, the wildcard
`\*` (indicating all types), or an identifier with embedded `*` and `..`
wildcards.

An embedded `*` in an identifier matches any sequence of characters, but
does not match the package (or inner-type) separator `.`.

An embedded `..` in an identifier matches any sequence of characters
that starts and ends with the package (or inner-type) separator `.`.

[[quick-advice]]
== Advice

Each piece of advice is of the form

[source, text]
....
[ strictfp ] AdviceSpec [ throws TypeList ] : Pointcut { Body }
....

where `AdviceSpec` is one of

`before( Formals )`::
  runs before each join point
`after( Formals ) returning [ ( Formal ) ]`::
  runs after each join point that returns normally. The optional formal
  gives access to the returned value
`after( Formals ) throwing [ ( Formal ) ]`::
  runs after each join point that throws a `Throwable`.
  If the optional formal is present, runs only after each join point
  that throws a `Throwable` of the type of `Formal`, and `Formal` gives access to the
  `Throwable` exception value
`after( Formals )`::
  runs after each join point regardless of whether it returns normally
  or throws a `Throwable`
`Type around( Formals )`::
  runs in place of each join point. The join point can be executed by
  calling `proceed`, which takes the same number and types of arguments as the around
  advice.

Three special variables are available inside of advice bodies:

`thisJoinPoint`::
  an object of type `org.aspectj.lang.JoinPoint` representing the join point
  at which the advice is executing
`thisJoinPointStaticPart`::
  equivalent to `thisJoinPoint.getStaticPart()`, but may use fewer runtime resources
`thisEnclosingJoinPointStaticPart`::
  the static part of the dynamically enclosing join point

[[quick-interType]]
== Inter-type member declarations

Each inter-type member is one of

`Modifiers ReturnType OnType . Id ( Formals ) [ throws TypeList ] { Body }`::
  a method on `OnType`
`abstract Modifiers ReturnType OnType . Id ( Formals ) [ throws TypeList ] ;`::
  an abstract method on `OnType`
`Modifiers OnType .  new ( Formals ) [ throws TypeList ] { Body }`::
  a constructor on `OnType`
`Modifiers Type OnType . Id [ = Expression ] ;`::
  a field on `OnType`

[[quick-other]]
== Other declarations

`declare parents : TypePattern extends Type ;`::
  the types in `TypePattern` extend `Type`
`declare parents : TypePattern implements TypeList ;`::
  the types in `TypePattern` implement the types in `TypeList`
`declare warning : Pointcut : String ;`::
  if any of the join points in `Pointcut` possibly exist in the program,
  the compiler emits the warning `String`
`declare error : Pointcut : String ;`::
  if any of the join points in `Pointcut` could possibly exist in the program,
  the compiler emits the error `String`
`declare soft : Type : Pointcut ;`::
  any `Type` exception that gets thrown at any join point picked out by `Pointcut`
  is wrapped in `org.aspectj.lang.SoftException`
`declare precedence : TypePatternList ;`::
  at any join point where multiple pieces of advice apply, the advice
  precedence at that join point is in `TypePatternList` order

[[quick-aspectAssociations]]
== Aspects

Each aspect is of the form

[source, text]
....
[ privileged ] Modifiers aspect Id [ extends Type ] [ implements TypeList ] [ PerClause ] { Body }
....

where `PerClause` defines how the aspect is instantiated and associated
(`issingleton()` by default):

[cols=",,",options="header",]
|===
|PerClause |Description |Accessor
|[ `issingleton()` ] |One instance of the aspect is made. This is the
default. |`aspectOf()` at all join points

|`perthis(Pointcut)` |An instance is associated with each object that is
the currently executing object at any join point in `Pointcut`.
|`aspectOf(Object)` at all join points

|`pertarget(Pointcut)` |An instance is associated with each object that
is the target object at any join point in `Pointcut`.
|`aspectOf(Object)` at all join points

|`percflow(Pointcut)` |The aspect is defined for each entrance to the
control flow of the join points defined by `Pointcut`. |`aspectOf()` at
join points in `cflow(Pointcut)`

|`percflowbelow(Pointcut)` |The aspect is defined for each entrance to
the control flow below the join points defined by `Pointcut`.
|`aspectOf()` at join points in `cflowbelow(Pointcut)`
|===