#include <jtie_tconv_idcache_impl.hpp>

Inheritance diagram for MemberId< C >:

Public Types
typedef C::memberID_t	ID_t

Static Public Member Functions
static void	setClass (JNIEnv *env, jclass cls)
static jclass	getClass (JNIEnv *env)
static ID_t	getId (JNIEnv *env, jclass cls)
static void	releaseRef (JNIEnv *env, jclass cls)

Static Public Attributes
static unsigned long	nIdLookUps = 0

Detailed Description

template<typename C>
struct MemberId< C >

Provides uniform access to the JNI Field/Method ID of a Java class member as described by the member info type 'C'.

This base class does not cache the member ID and the class object, but it retrieves the member ID from JNI upon each access; different caching strategies are provided by derived classes.

This class (and its derived classes) impose a strict usage pattern. For example, given definitions...

// Defines the field info type for MyClass.myField. JTIE_DEFINE_FIELD_MEMBER_INFO(_MyClass_myField)

// Provides a (cached) access to field Id of MyClass.myField. typedef JniMemberId< _MyClass_myField > MyClass_myField;

any use of a member ID must be bracketed by getClass() and releaseRef():

// obtain a class reference jclass cls = MyClass_myField::getClass(env); if (cls == NULL) { // exception pending } else { // get the field ID valid along with the class reference jfieldID fid = MyClass_myField::getId(env, cls); if (fid == NULL) { // exception pending } else { // OK to access field using 'fid' } // allow for releasing the class reference MyClass_myField::releaseRef(env, cls); }

Derived classes implement any caching underneath this usage pattern.

Definition at line 156 of file jtie_tconv_idcache_impl.hpp.

Member Function Documentation

template<typename C >

static jclass MemberId< C >::getClass ( JNIEnv * env )

inlinestatic

Returns a JNI Reference to the class declaring the member specified by info type 'C'.

Depending upon the underlying caching strategy, a returned reference may be local or global, weak or strong; the scope of its use must be demarcated by releaseRef().

Pre condition:

this thread has no pending JNI exception (!env->ExceptionCheck())

Post condition:

return value is NULL:
- this thread has a pending JNI exception (env->ExceptionCheck()) otherwise:
- this thread has no pending JNI exception (!env->ExceptionCheck())
- the returned reference is valid (at least) until releaseRef()

Reimplemented in MemberIdPreloadedStrongCache< C >, MemberIdPreloadedWeakCache< C >, MemberIdStrongCache< C >, and MemberIdWeakCache< C >.

Definition at line 196 of file jtie_tconv_idcache_impl.hpp.

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template<typename C >

static ID_t MemberId< C >::getId	(	JNIEnv *	env,
		jclass	cls
	)

inlinestatic

Returns the JNI Field/Method ID of a Java class member.

The member ID is only valid along with a class object obtained by getClass() and before releaseRef().

Pre condition:

this thread has no pending JNI exception (!env->ExceptionCheck())
a valid class reference obtained by getClass(): assert(cls != NULL)

Post condition:

return value is NULL:
- this thread has a pending JNI exception (env->ExceptionCheck()) otherwise:
- this thread has no pending JNI exception (!env->ExceptionCheck())
- the returned member ID is valid (at least) until releaseRef()

Reimplemented in MemberIdCache< C >.

Definition at line 239 of file jtie_tconv_idcache_impl.hpp.

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