admin@glassfish.java.net

Re: Glassfish V3: should AMX preserve create() methods for backwards compatibility?

From: Jerome Dochez <Jerome.Dochez_at_Sun.COM>
Date: Mon, 17 Mar 2008 22:20:05 -0700

So if I understand the pattern correctly, you have named parameters
for required parameters and all others are passed in the optional map ?

so we have some like :

<T> T createTConfig(T.param1, T.param2, Map<String, String optionals)

T.param1 are @Attribute declared on T with required=true, all other T
attributes go in optionals.

for Instance take in Domain.java, for JdbcResource, the above
automatic mapping with today's @Attribute would lead to

JdbcResource createJdbcResourceConfig(String jndi-name, String pool-
name, Map<String, String> optionals);

that seem remarkably close to https://glassfish.dev.java.net/nonav/javaee5/amx/javadoc/com/sun/appserv/management/config/DomainConfig.html
#createJDBCResourceConfig(java.lang.String,%20java.lang.String,
%20java.util.Map)

but of course, it's only 1 example. do you think this could work
generically ?

jerome

On Mar 17, 2008, at 11:05 AM, Lloyd L Chambers wrote:

> Jerome,
>
> I am averse to any system that would require special processing to
> generate the info ("APT"). An annotation is something that anyone
> can add and compile at will with any build system eg a 3rd party
> with their own build system or java compiler--and it seems very
> straightforward. But I don't understand your proposal about APT.
>
> For an example of the types of create() methods seen today, take a
> look at AMX DomainConfig:
> https://glassfish.dev.java.net/nonav/javaee5/amx/javadoc/com/sun/appserv/management/config/DomainConfig.html
>
> All AMX creation methods for config start with "create" and end with
> "Config" and are scoped by the containing AMXConfig MBean
> ("Container"). These facts allow enough knowledge about what to be
> created to implement it in general (I think).
>
> There are alternatives to methods with specific names. AMX could
> offer this type of generic facility:
> create( String j2eeType, Map<String,String> attributes );
>
> But the above actually introduces additional complexities (eg
> required parameters are not specified), and it breaks backward
> compatibility.
>
> Lloyd
>
> On Mar 17, 2008, at 10:47 AM, Jerome Dochez wrote:
>
>>
>> On Mar 17, 2008, at 10:17 AM, Lloyd L Chambers wrote:
>>
>>> Jerome,
>>>
>>> The AMX code does map names back and forth already. But there are
>>> no names to begin with--an MBean operation will be invoked like
>>> this:
>>>
>>> public final Object invoke(
>>> String operationName,
>>> Object[] args,
>>> String[] types )
>>>
>>> There are no argument names here, so nothing to use for mapping.
>>> AMX needs to map args[1..N] to names which can eventually result
>>> in xml property names.
>>>
>>> If a method to create an "Abc" eg createAbc() method has been
>>> declared in the AMX interface, then the args could be matched up
>>> to the parameter names, but HOW?
>>>
>> I understand now, thanks
>>> I don't know of any mechanism to get the *names* of parameters
>>> from a java.lang.reflect.Method, or can you?
>> no there isn't a way to do that with reflection but we could use
>> APT to generate that information automatically.
>>
>> where would these createABC be located ?
>>
>> Jerome
>>
>>> That is why I thought an annotation was needed, which would allow
>>> the names of each parameter in the parameter list to be named.
>>>
>>> Lloyd
>>>
>>> On Mar 14, 2008, at 10:44 PM, Jerome Dochez wrote:
>>>
>>>> for issue 2, I don't understand why you cannot (at least for 99%
>>>> of the cases) calculate automatically the amx name from the xml
>>>> name and the other way around. seems extremely verbose to me if
>>>> you have to specify it on an annotation when the mapping is
>>>> simple like in you previous email
>>>>
>>>> ex:
>>>> @ParamNames("jndi-name","jndi-lookup-name","res-type","factory-
>>>> class")
>>>> createJNDIResourceConfig( String jndiName, String jndiLookupName,
>>>> String resType, String factoryClass, Map<String,String> optional);
>>>>
>>>>
>>>> On Mar 14, 2008, at 9:56 AM, Lloyd Chambers wrote:
>>>>
>>>>> Jerome et al,
>>>>>
>>>>> To support AMX create(), I need a few things which perhaps you
>>>>> can tell me how to do—
>>>>>
>>>>> => ISSUE 1: locating an @Configured
>>>>>
>>>>> To locate the @Configured interface corresponding to an AMX
>>>>> j2eeType. This value is found in the @AMXConfigInfo, which
>>>>> annotates an @Configured interface. AMX requires that any
>>>>> module desiring automatic AMXConfig support annotate its config
>>>>> with @AMXConfigInfo. So I need to do this (in some form):
>>>>>
>>>>> for ( final Class<? extends AMXConfig> configIntf :
>>>>> allConfiguredClasses ) {
>>>>> AMXConfigInfo configInfo =
>>>>> configIntf.getAnnotation( AMXConfigInfo.class );
>>>>> if ( configInfo != null &&
>>>>> configInfo.j2eeType().equals( j2eeType ) {
>>>>> // found a match
>>>>> break;
>>>>> }
>>>>> }
>>>>> Such a loop could be run just once (on demand when the first
>>>>> create() is done), and a Map could be created at that time for
>>>>> future efficiency. Alternately, it could exit as soon as the
>>>>> required value were found.
>>>>>
>>>>> Alternately, create() is always implicitly for a child
>>>>> (Containee) and therefore the only classes that need to be
>>>>> searched are those that are child elements of an existing
>>>>> ConfigBean. Is there a method to get all possible child
>>>>> interfaces for a given ConfigBean (not just those that currently
>>>>> exist)?
>>>>>
>>>>> => ISSUE 2: mapping parameter names
>>>>>
>>>>> To support create() methods with explicit parameter lists. For
>>>>> example:
>>>>>
>>>>> createJNDIResourceConfig( String jndiName, String
>>>>> jndiLookupName, String resType, String factoryClass,
>>>>> Map<String,String> optional);
>>>>>
>>>>> The problem here is mapping jndiName, jndiLookupName, resType
>>>>> and factoryClass to XML names; as incoming parameters they are
>>>>> simple indexed values in the parameter list, lacking any sort of
>>>>> name. AMX solves this today by having small mapping tables
>>>>> internally, but that means special code for every such method,
>>>>> something we must avoid in a pluggable system.
>>>>>
>>>>> I’m thinking of using an annotation which specifies the names
>>>>> for explicit parameters:
>>>>>
>>>>> @Target(ElementType.METHOD)
>>>>> public @interface ParamNames {
>>>>> /** comma-delimited list of parameter names, in order */
>>>>> String paramNames default "";
>>>>> }
>>>>>
>>>>> ex:
>>>>> @ParamNames("jndi-name","jndi-lookup-name","res-type","factory-
>>>>> class")
>>>>> createJNDIResourceConfig( String jndiName, String
>>>>> jndiLookupName, String resType, String factoryClass,
>>>>> Map<String,String> optional);
>>>>>
>>>>> Thoughts?
>>>>>
>>>>> Lloyd
>>>>>
>>>>> Begin forwarded message:
>>>>>
>>>>>> From: Lloyd Chambers <lloyd.chambers_at_mac.com>
>>>>>> Date: March 14, 2008 9:36:02 AM PDT
>>>>>> To: admin_at_glassfish.dev.java.net
>>>>>> Subject: Glassfish V3: should AMX preserve create() methods
>>>>>> for backwards compatibility?
>>>>>>
>>>>>> This is a sort of “thinking aloud” and request for feedback all
>>>>>> in one—
>>>>>>
>>>>>> Background
>>>>>>
>>>>>> - In V3 arbitrary modules can be loaded, including ones
>>>>>> designed and compiled after the product ships
>>>>>> - AMX supports configuration MBeans for such modules
>>>>>> automagically with a simple annotation on the @Configured
>>>>>> interface supplied by the module
>>>>>>
>>>>>> In V2, AMX supported creation of sub-elements with createAbc()
>>>>>> methods that included a parameter list with explicit parameters
>>>>>> for required values and optional parameters provided in a
>>>>>> Map<String,String>. Here are a few examples from DomainConfig:
>>>>>>
>>>>>> createStandaloneServerConfig(String name, String nodeAgentName,
>>>>>> String configName, Map<String,String> optional);
>>>>>>
>>>>>> createConfigConfig( String name, Map<String,String> optional );
>>>>>>
>>>>>> createLoadBalancerConfig(String name, String lbConfigName,
>>>>>> boolean autoApplyEnabled, Map<String,String> optional);
>>>>>>
>>>>>> createJNDIResourceConfig( String jndiName, String
>>>>>> jndiLookupName, String resType, String factoryClass,
>>>>>> Map<String,String> optional);
>>>>>>
>>>>>> createJDBCConnectionPoolConfig( String name,
>>>>>> String connectionValidationMethod,
>>>>>> String datasourceClassname,
>>>>>> boolean failAllConnections,
>>>>>> int idleTimeoutSeconds,
>>>>>> boolean connectionValidationRequired,
>>>>>> boolean isolationLevelGuaranteed,
>>>>>> String transactionIsolationLevel,
>>>>>> int maxPoolSize,
>>>>>> int maxWaitTimeMillis,
>>>>>> int poolResizeQuantity,
>>>>>> String resType,
>>>>>> int steadyPoolSize,
>>>>>> String databaseName,
>>>>>> String databaseUserName,
>>>>>> String databasePassword,
>>>>>> Map<String,String> reservedForFutureUse );
>>>>>>
>>>>>> Question: In Glassfish V3, should AMX preserve methods like the
>>>>>> ones shown above?
>>>>>>
>>>>>> (and allow/support such methods in new/unknown AMX interfaces
>>>>>> supplied by arbitrary modules)
>>>>>>
>>>>>> I think the answer is “yes”, so long as the backend can
>>>>>> implement this support generically: AMX needs to be able to
>>>>>> turn the parameter list into a generic form (eg a Map) which
>>>>>> can be generically set on a ConfigBean. AMX can supply the
>>>>>> “glue” code to transform the explicit and optional parameters
>>>>>> into a form which can be used to set values on a ConfigBean eg:
>>>>>>
>>>>>> public MyConfig createContainee( final String j2eeType, final
>>>>>> Map<String,String> values );
>>>>>>
>>>>>> implemented by:
>>>>>>
>>>>>> final ConfigBean configBean =
>>>>>> instantiateConfigBeanForJ2EEType( j2eeType );
>>>>>> for( final String fieldName : values.keySet() ) {
>>>>>> configBean.attribute( amxNameToXmlName( fieldName ),
>>>>>> values.get( fieldName ) );
>>>>>> }
>>>>>>
>>>>>> Fortunately, the j2eeType value is found in the @AMXConfigInfo,
>>>>>> so this all ought to work OK.
>>>>>>
>>>>>> Lloyd
>>>>>
>>>>
>>>
>>> ---
>>> Lloyd L Chambers
>>> lloyd.chambers_at_sun.com
>>> Sun Microsystems, Inc
>>>
>>>
>>>
>>
>
> ---
> Lloyd L Chambers
> lloyd.chambers_at_sun.com
> Sun Microsystems, Inc
>
>
>