/// <summary>
/// invokes the method. Returns null if a problem, the
/// actual return if the method returns something, or
/// an empty string "" if the method returns void
/// </summary>
public override Object Execute(Object o, IInternalContextAdapter context)
{
IDuck duck = o as IDuck;
object[] parameters = new object[paramCount];
if (duck != null)
{
EvalParameters(parameters, context);
return(duck.Invoke(methodName, parameters));
}
/*
* new strategy (strategy!) for introspection. Since we want
* to be thread- as well as context-safe, we *must* do it now,
* at execution time. There can be no in-node caching,
* but if we are careful, we can do it in the context.
*/
MethodInfo method = null;
PropertyInfo property = null;
bool preparedAlready = false;
object[] methodArguments = new object[paramCount];
try
{
/*
* check the cache
*/
IntrospectionCacheData introspectionCacheData = context.ICacheGet(this);
Type c = o.GetType();
/*
* like ASTIdentifier, if we have cache information, and the
* Class of Object o is the same as that in the cache, we are
* safe.
*/
EvalParameters(parameters, context);
if (introspectionCacheData != null && introspectionCacheData.ContextData == c)
{
preparedAlready = true;
/*
* and get the method from the cache
*/
if (introspectionCacheData.Thingy is MethodInfo)
{
method = (MethodInfo)introspectionCacheData.Thingy;
methodArguments = BuildMethodArgs(method, parameters, paramArrayIndex);
}
if (introspectionCacheData.Thingy is PropertyInfo)
{
property = (PropertyInfo)introspectionCacheData.Thingy;
}
}
else
{
/*
* otherwise, do the introspection, and then
* cache it
*/
Object obj = PerformIntrospection(context, c, parameters);
if (obj is MethodInfo)
{
method = (MethodInfo)obj;
}
if (obj is PropertyInfo)
{
property = (PropertyInfo)obj;
}
if (obj != null)
{
introspectionCacheData = new IntrospectionCacheData();
introspectionCacheData.ContextData = c;
introspectionCacheData.Thingy = obj;
context.ICachePut(this, introspectionCacheData);
}
}
/*
* if we still haven't gotten the method, either we are calling
* a method that doesn't exist (which is fine...) or I screwed
* it up.
*/
if (method == null && property == null)
{
return(null);
}
}
catch (Exception ex)
{
runtimeServices.Error(string.Format("ASTMethod.execute() : exception from introspection : {0}", ex));
throw new RuntimeException(
String.Format(
"Error during object introspection. Check inner exception for details. Node literal {0} Line {1} Column {2}",
base.Literal, Line, Column), ex);
}
try
{
/*
* get the returned object. It may be null, and that is
* valid for something declared with a void return type.
* Since the caller is expecting something to be returned,
* as long as things are peachy, we can return an empty
* String so ASTReference() correctly figures out that
* all is well.
*/
Object obj;
if (method == null)
{
obj = property.GetValue(o, null);
}
else
{
if (!preparedAlready)
{
methodArguments = BuildMethodArgs(method, parameters);
}
obj = method.Invoke(o, methodArguments);
if (obj == null && method.ReturnType == typeof(void))
{
obj = String.Empty;
}
}
return(obj);
}
catch (TargetInvocationException targetInvocationException)
{
/*
* In the event that the invocation of the method
* itself throws an exception, we want to catch that
* wrap it, and throw. We don't log here as we want to figure
* out which reference threw the exception, so do that
* above
*/
EventCartridge eventCartridge = context.EventCartridge;
/*
* if we have an event cartridge, see if it wants to veto
* also, let non-Exception Throwables go...
*/
if (eventCartridge == null)
{
/*
* no event cartridge to override. Just throw
*/
throw new MethodInvocationException(
string.Format("Invocation of method '{0}' in {1} threw exception {2} : {3}", methodName, o.GetType(),
targetInvocationException.GetBaseException().GetType(),
targetInvocationException.GetBaseException().Message), targetInvocationException,
methodName);
}
else
{
try
{
return(eventCartridge.HandleMethodException(o.GetType(), methodName, targetInvocationException));
}
catch (Exception e)
{
throw new MethodInvocationException(
string.Format("Invocation of method '{0}' in {1} threw exception {2} : {3}", methodName, o.GetType(),
e.GetType(), e.Message), e, methodName);
}
}
}
catch (Exception e)
{
runtimeServices.Error(
string.Format("ASTMethod.execute() : exception invoking method '{0}' in {1} : {2}", methodName, o.GetType(), e));
throw;
}
}