I would like to implement lazy loading on properties with PostSharp.
To make it short, instead of writing
SomeType _field = null;
private SomeType Field
{
get
{
if (_field == null)
{
_field = LongOperation();
}
return _field;
}
}
I would like to write
[LazyLoadAspect]
private object Field
{
get
{
return LongOperation();
}
}
So, I identify that I need to emit some code in the class to generate the backing field, as well as inside the getter method in order to implement the test.
With PostSharp, I was considering overriding CompileTimeInitialize
, but I am missing the knowledge to get a handle over the compiled code.
EDIT: The question can be extended to any parameterless method like:
SomeType _lazyLoadedField = null;
SomeType LazyLoadableMethod ()
{
if(_lazyLoadedField ==null)
{
// Long operations code...
_lazyLoadedField = someType;
}
return _lazyLoadedField ;
}
would become
[LazyLoad]
SomeType LazyLoadableMethod ()
{
// Long operations code...
return someType;
}
After our comments, I think I know what you want now.
[Serializable]
public class LazyLoadGetter : LocationInterceptionAspect, IInstanceScopedAspect
{
private object backing;
public override void OnGetValue(LocationInterceptionArgs args)
{
if (backing == null)
{
args.ProceedGetValue();
backing = args.Value;
}
args.Value = backing;
}
public object CreateInstance(AdviceArgs adviceArgs)
{
return this.MemberwiseClone();
}
public void RuntimeInitializeInstance()
{
}
}
Test code
public class test
{
[LazyLoadGetter]
public int MyProperty { get { return LongOperation(); } }
}