Hi,
Let me give a try:
1) @target
a) An SCA service represents a business function that a component provides,
for example, a book store selling books.
b) An SCA reference represents a business function that a component
consumes, for example, book store needs to use shopping cart and catalog.
The 'target' attribute of <reference> points to an SCA service that can
provide the business function required by the reference. For example, if the
BookStore component has a catalog reference as follows:
<component name="BookStoreComponent">
<reference name="catalog" target="CatalogComponent/Catalog"/>
</component>
<component name="CatalogComponent">
...
</component>
The @target says CatalogComponent's Catalog service is the provider for
catalog reference. If you change it to "NewCatalogComponent/Catalog", you
basically switch to a new service provider: NewCatalogComponent's Catalog
service.
2) @promote
In SCA, a pre-assembled composite can be reused as a building block for
compositions. It's achieved by <implementation.composite>. For example, the
Catalog service itself can be developed as a SCA composite. Inside the
Catalog composite, there could be a few java components.
<component name="CatalogComponent>
<implementation.composite composite="ns1:CatalogComposite"/>
...
</component>
Now the question is what services/references in the CatalogComposite will be
made public for CatalogComponent. Service/Reference promotion is introduced
for this purpose.
For example,
<composite name="CatalogComposite">
<service name="Catalog"
promote="InternalCatalogComponent/InternalCatalog">
...
</service>
<reference name="parnterCatalog"
promote="InternalCatalogComponent/partnerCatalog">
...
</reference>
<component name="InternalCatalogComponent>
...
</component>
</composite>
The @promote for the <service> says if CatalogComposite is used as a
component for assembly, there is a service named Catalog that makes the
InternalCatalogComponent's InternalCatalog service public. As a result, the
CatalogComponent has a public Catalog service that can be wired to.
The @promote for the <reference> says if CatalogComposite is used as a
component for assembly, there is a reference named partnerCatalog that makes
the InternalCatalogComponent's partnerCatalog reference public. As a result,
the CatalogComponent has a public partnerCatalog reference and a service
provider can be defined for this reference.
Thanks,
Raymond
--------------------------------------------------
From: "Fengxiang" <[EMAIL PROTECTED]>
Sent: Sunday, March 23, 2008 2:06 AM
To: <[email protected]>
Subject: Ask for help on promot and target
Dear all,
My mother luangage is not english.So I can't got an deep understand with
the
specification document of assembly of sca.
Especially on attribution of promot and target, Could you give me an
detail
explaination .
Thanks.
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