This looks fine to me. Nice little optimization (which is no doubt repeated thousands of times for significant wins).
Mike On Mar 26 2013, at 15:43 , Joe Darcy wrote: > Hello, > > Please review this refactoring of how annotations objects are created: > > JDK-7185456 : (ann) Optimize Annotation handling in java/sun.reflect.* > code for small number of annotationsC > http://cr.openjdk.java.net/~darcy/7185456.0/ > > In brief, an annotation object is backed by a hash map with one entry per > method defined on the annotation type. Currently the default HashMap > constructor which uses a default capacity of 16 is used. Since most > annotation type define many fewer methods, some space is wasted. The patch > (inline below) "right sizes" the HashMap to match the number of methods in > the annotation type. > > Thanks, > > -Joe > > --- old/src/share/classes/sun/reflect/annotation/AnnotationType.java > 2013-03-26 15:37:22.000000000 -0700 > +++ new/src/share/classes/sun/reflect/annotation/AnnotationType.java > 2013-03-26 15:37:22.000000000 -0700 > @@ -45,19 +45,18 @@ > * types. This matches the return value that must be used for a > * dynamic proxy, allowing for a simple isInstance test. > */ > - private final Map<String, Class<?>> memberTypes = new > HashMap<String,Class<?>>(); > + private final Map<String, Class<?>> memberTypes; > > /** > * Member name -> default value mapping. > */ > - private final Map<String, Object> memberDefaults = > - new HashMap<String, Object>(); > + private final Map<String, Object> memberDefaults; > > /** > * Member name -> Method object mapping. This (and its assoicated > * accessor) are used only to generate AnnotationTypeMismatchExceptions. > */ > - private final Map<String, Method> members = new HashMap<String, > Method>(); > + private final Map<String, Method> members; > > /** > * The retention policy for this annotation type. > @@ -105,6 +104,9 @@ > } > }); > > + memberTypes = new HashMap<String,Class<?>>(methods.length+1, 1.0f); > + memberDefaults = new HashMap<String, Object>(0); > + members = new HashMap<String, Method>(methods.length+1, 1.0f); > > for (Method method : methods) { > if (method.getParameterTypes().length != 0)
