Date: 2004-12-07T02:13:53
Editor: KenTam <[EMAIL PROTECTED]>
Wiki: Apache Beehive Wiki
Page: Controls/ControlsVersioning
URL: http://wiki.apache.org/beehive/Controls/ControlsVersioning
no comment
New Page:
= Controls Versioning Model =
== Overview ==
There are important use cases for controls where the various related artifacts
(interfaces, extensions, implementations) are developed by different
people/organizations, and as those artifacts evolve over time it becomes useful
to be able to specify versioning information and require certain version
values. The controls programming model features a number of annotations to
support this.
== Defining a Version ==
{{{
package org.apache.beehive.controls.api.versioning;
public @inteface Version
{
int major();
int minor() default 0;
}
}}}
The @V''''''ersion annotation:
* Is allowed on control interfaces (annotated with @C''''''ontrolInterface).
* Defines a version of the control interface and is the basis of controls
versioning.
* Is retained in interface class file (not BeanInfo!)
== Specifying Version Restrictions/Requirements ==
{{{
package org.apache.beehive.controls.api.versioning;
public @interface VersionRequired
{
int major;
int minor default -1;
}
}}}
The @V''''''ersionRequired annotation:
* Is allowed on control extensions and controls field declarations.
* Defines the minimum versions of the control interface that this extension or
field requires.
* Major version mandatory, minor is optional (default is to not require any
specific minor ver).
* When extension or client is compiled, version requirement is enforced
against the control interface found at that time.
* When extension's control bean is is classloaded, version requirement is
statically enforced against the control interface found at that time.
{{{
public @interface VersionSupported
{
int major;
int minor default -1;
}
}}}
The @V''''''ersionSupported annotation:
* Is allowed on control implementations.
* Defines the maximum versions of the control interface that this
implementation supports.
* Major version mandatory, minor is optional (default is to support all minor
versions).
* When implementation is compiled, version requirement is enforced against the
control interface found at that time.
* When implementation is classloaded, version requirement is statically
enforced against the control interface found at that time.
== Open Issues ==
* Static runtime enforcement may run into problems in complex classloader
situations (where interfaces and impls come from different classloaders).
Perhaps add a way to disable runtime checks?
