org.objectweb.jac.wrappers
Class LimiterWrapper

java.lang.Object
  |
  +--org.objectweb.jac.core.Wrapper
        |
        +--org.objectweb.jac.wrappers.LimiterWrapper

All Implemented Interfaces:

Advice, ConstructorInterceptor, Interceptor, MethodInterceptor, Serializable

public class LimiterWrapper

extends Wrapper

LimiterWrapper implements a wrapper that tests a counter value before calling the wrappee object. If the counter is not with the max and min limits, it raises the LimiterException

Use this wrapper as follows:

 LimiterWrapper lw = new LimiterWrapper(0, 100);
 a_stack.wrap(lw, "inc", "push");
 a_stack.wrap(lw, "dec", "pop");
 a_stack.wrap(lw, "testMax", "push");
 a_stack.wrap(lw, "testMin", "pop");
 

Where a_stack is an instance of a class Stack. When wrapping the stack, it will raise a LimiterException if a push is done and that the counter is greater or equal to 100 or if a pop is done and that the counter is lower or equal to 0.

NOTE: this class cannot be used alone. Its instances must wrap some instances of other objects (possibly other wrappers).

See Also:

Wrappee, Wrapping.wrap(Wrappee,Wrapper,AbstractMethodItem), LimiterException, Serialized Form

Field Summary

protected int	counter Store the counter of the limiter.
protected int	max Store the maximum bound of the limiter.
protected int	min Store the minimum bound of the limiter.

Fields inherited from class org.objectweb.jac.core.Wrapper

ac, cr

Constructor Summary

LimiterWrapper(AspectComponent ac, int min, int max)
Construct a new limiter and initialize the bounds.

Method Summary

Object	construct(ConstructorInvocation invocation)
Object	dec(Interaction interaction) This wrapping method decrements the limiter counter and calls the wrappee method.
int	getCounter() Return the current counter of the limiter.
int	getMax() Return the max bound of the limiter.
Object	inc(Interaction interaction) This wrapping method increments the limiter counter and calls the wrappee method.
Object	invoke(MethodInvocation invocation)
void	setMax(int max) Set the max bound of the limiter.
Object	testMax(Interaction interaction) This wrapping method tests the counter of the limiter and raises the LimiterExeption when when it is over the maximum value.
Object	testMin(Interaction interaction) This wrapping method tests the counter of the limiter and raises the LimiterExeption when when it is below the minimum value.

Methods inherited from class org.objectweb.jac.core.Wrapper

attr, attrdef, defines, getAspectComponent, getAspectComponentName, getExceptionHandlers, proceed, toString

Methods inherited from class java.lang.Object

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

Field Detail

max

protected int max

Store the maximum bound of the limiter.

min

protected int min

Store the minimum bound of the limiter.

counter

protected int counter

Store the counter of the limiter.

Constructor Detail

LimiterWrapper

public LimiterWrapper(AspectComponent ac,
                      int min,
                      int max)

Construct a new limiter and initialize the bounds.

Parameters:

min - the minimum counter value.

max - the maximum counter value.

Method Detail

getMax

public int getMax()

Return the max bound of the limiter.

Returns:

the max bound

setMax

public void setMax(int max)

Set the max bound of the limiter.

Parameters:

max - the new max bound

getCounter

public int getCounter()

Return the current counter of the limiter.

Returns:

the counter

inc

public Object inc(Interaction interaction)

This wrapping method increments the limiter counter and calls the wrappee method.

For instance, inc could wrap the push method of a stack so that the counter is incremented when a new element is placed on the top of the stack.

NOTE: this method do not test the bounds. Use testMax to do this.

Returns:

the original method return value

See Also:

testMax(Interaction)

dec

public Object dec(Interaction interaction)

This wrapping method decrements the limiter counter and calls the wrappee method.

For instance, dec could wrap the pop method of a stack so that the counter is incremented when an element is removed from it.

NOTE: this method do not test the bounds. Use testMin to do this.

Returns:

the original method return value

See Also:

testMin(Interaction)

testMax

public Object testMax(Interaction interaction)
               throws LimiterException

This wrapping method tests the counter of the limiter and raises the LimiterExeption when when it is over the maximum value.

NOTE: this method must be used with the inc and dec wrapping methods that mofify the counter value.

Returns:

the original method return value or raise an exception

LimiterException

See Also:

inc(Interaction), dec(Interaction)

testMin

public Object testMin(Interaction interaction)
               throws LimiterException

This wrapping method tests the counter of the limiter and raises the LimiterExeption when when it is below the minimum value.

NOTE: this method must be used with the inc and dec wrapping methods that mofify the counter value.

Returns:

the original method return value or raise an exception

LimiterException

See Also:

inc(Interaction), dec(Interaction)

invoke

public Object invoke(MethodInvocation invocation)
              throws Throwable

Specified by:

invoke in interface MethodInterceptor

Overrides:

invoke in class Wrapper

Throwable

construct

public Object construct(ConstructorInvocation invocation)
                 throws Throwable

Specified by:

construct in interface ConstructorInterceptor

Overrides:

construct in class Wrapper

Throwable