Changeset 37d941 for src/CodePatterns

Timestamp:

Aug 30, 2013, 10:52:22 PM (12 years ago)

Author:

Frederik Heber <heber@…>

Children:

b324a3

Parents:

f1df08

Message:

Cacheable may be used without an active Observable.

• this allows to use Cacheable pattern as a simple lazy evaluation. If the actual calculation is expensive but the object never changes, this can be very beneficial.

File:

• src/CodePatterns/Cacheable.hpp (modified) (3 diffs)

src/CodePatterns/Cacheable.hpp

@@ -180 +180 @@
     // we sign on with the best(=lowest) priority, so cached values are recalculated before
     // anybody else might ask for updated values
-    owner->signOn(this,Observable::PriorityLevel(int(-20)));
+    if (owner != NULL)
+      owner->signOn(this,Observable::PriorityLevel(int(-20)));
   }
 
@@ -192 +193 @@
   const T Cacheable<T>::operator*() const{
     // we can only use the cacheable when the owner is not changing at the moment
-    if(!owner->isBlocked()){
+    if ((owner == NULL) || (!owner->isBlocked())) {
       return state->getValue();
     }
@@ -203 +204 @@
   Cacheable<T>::~Cacheable()
   {
-    owner->signOff(this);
+    if (owner != NULL)
+      owner->signOff(this);
   }