Compliance relationship and scope of feature activation of WSS3SDK

The compliance of feature activation indicates that there are necessary relationships between two feature. You can express the activation compliance relationship, whether within the same range, or across different ranges of feature. Cross-scope activation compliance is a guide to a specific range of feature activation must require a different range of the other feature also in the active state. An example of a typical cross scope activation is the site feature compliance with site collection feature.

You typically use an activation compliance relationship for the following two purposes:

The concept of the feature group when one feature is activated, another feature can also be activated. For example, when the default workgroup collaboration Feature (under \12\template \features\teamcollab) is activated, he activates many other Feature by activating a dependency. When you activate a workgroup collaboration feature, he activates its compliant feature to make a specific list template available. When you close the feature, its compliant feature is also closed (if no other feature follow him), the list template becomes unusable.

Feature resource protection You may need a site collection feature to contain resources, such as a content type, and then include the implementation in a Web site feature. You can ensure that all feature are activated by activating compliance.

Activating compliance Rules

Activation compliance must conform to certain rules in order to avoid situations such as cyclic compliance, compliance chains, etc. that affect performance.

Rules of the same scope

If a feature is compliant with another feature in the same range, and the second feature is turned off when the first feature is activated, WSS activates the second Featuer.

If a feature is closed, WSS closes the hidden feature that the feature complies with in the same range (when the last visible feature is closed in compliance with the feature).

Cross-scope rule

If the feature is compliant on a smaller scale, then the cross Range activation compliance will not be supported. For example, a site collection feature cannot be compliant with a website feature.

If feature is compliant with an invisible feature, activation compliance will not support cross scope. In other words, a site-wide feature cannot be compliant with a site collection-wide feature that is not visible in the UI.

If the feature being complied with is closed, the activation of feature will fail. For example, if a site feature complies with a site collection feature, and the site collection feature is closed, it will fail when it is provided feature the site (or the site definition that contains feature for the site).

General rules

Compliance only has a effect on the depth of a layer. In other words, the compliance chain is not supported. WSS does not support more than one layer of activation compliance relationships (if the final feature is visible). That is to say, a visible feature complies with the second visible feature, followed by the third visible feature. However, WSS supports a visible feature compliance with the second visible feature, followed by the third hidden feature.

You can point the compliance to a hidden or visible feature, but the hidden feature cannot have activation compliance. The hidden property of the feature element determines whether the feature is displayed in the UI.

When multiple feature are compliant with a given feature, beware of the danger of placing one of the feature in the wrong environment. For example, suppose you have a visible site collection range of feature named Feature B, which is compliant to a hidden site collection scope feature named feature a. There is also a third visible site-wide feature, named Feature C, which is also compliant with Featurea. Feature B's shutdown also closes Feature A, which puts Feature C in the wrong place.