Re: [sca-j] Why is @Property.required attribute MUST be true forconstructor parameter?

[Raymond Feng <rfeng@us.ibm.com>]

My understanding is that @required=true means
the property MUST be set with a value which can be either configured at
the component level or inherited from the componentType. 

For example, if we have a constructor as
follows:

public MyServiceImpl(@Property(name="myProp")
String myProp) {
        ...
} 

The injection for "myProp" is required
no matter what value it is set.

Thanks,
Raymond

From:	C Vamsi <vamsic007@in.ibm.com>
To:	sca-j@lists.oasis-open.org
Date:	02/23/2009 10:41 AM
Subject:	[sca-j] Why is @Property.required attribute MUST be true for constructor parameter?

---

sca-javacaa-1.1-spec-cd02-rev2.doc:

Sec 9.15 @Property

Lines 1622-1623:
required (optional) – specifies whether injection is required, defaults
to
true. For a constructor parameter annotation, this attribute MUST have
the
value true.

Q: Why is, "For a constructor parameter annotation, this attribute
MUST
have the value true." required?

The componentType can define a default value for the property. In this
case, even if a property is not specified in the component definition,
the
runtime will still have a value to pass as an argument to the constructor.


++Vamsi
Apache Tuscany Committer  http://tuscany.apache.org
Apache Geronimo Committer and Member of PMC  http://geronimo.apache.org

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