Groovy 2.2.1

groovy.transform
[Java] Annotation Type Memoized

java.lang.Object
  groovy.transform.Memoized

@Retention(RetentionPolicy.SOURCE)
@Target({ ElementType.METHOD })
@GroovyASTTransformationClass("org.codehaus.groovy.transform.MemoizedASTTransformation")
public @interface Memoized

Method annotation that creates a cache for the results of the execution of the annotated method. Whenever the method is called, the mapping between the parameters and the return value is preserved in a cache making subsequent calls with the same arguments fast.

Example usage:

 class MemoizedExample {
 
     @Memoized
     int sum(int n1, int n2) {
         println "$n1 + $n2 = ${n1 + n2}" 
         n1 + n2
     }
 }
 
which becomes (approximately):
 class MemoizedExample {
 
     private final Closure memoizedSum = { int n1, int n2 ->
         private$method$memoizedSum(n1,n2)
     }.memoize()
 
     int sum(int n1, int n2) {
         memoizedSum(n1, n2)
     }

     private private$method$mzmoizeSum(int n1, int n2) {
         println "$n1 + $n2 = ${n1 + n2}"
         n1 + n2
     }
 }
 

Upon execution of this code:

 def instance = new MemoizedExample()
 println instance.sum(1, 2)
 println instance.sum(1, 2)
 println instance.sum(2, 3)
 println instance.sum(2, 3)
 
The following will be output:
 1 + 2 = 3
 3
 3
 2 + 3 = 5
 5
 5
 
Authors:
Andrey Bloschetsov


 
Optional Element Summary
int maxCacheSize

The maximum size the cache can grow to.

int protectedCacheSize

Number of cached return values to protect from garbage collection.

 
Method Summary
 
Methods inherited from class Object
wait, wait, wait, equals, toString, hashCode, getClass, notify, notifyAll
 

Element Detail

maxCacheSize

public int maxCacheSize
The maximum size the cache can grow to. @default 0


protectedCacheSize

public int protectedCacheSize
Number of cached return values to protect from garbage collection. @default 0


 

Copyright © 2003-2013 The Codehaus. All rights reserved.