1 /*
2 * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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7 * published by the Free Software Foundation. Oracle designates this
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9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
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24 */
25
26
27 package com.sun.org.glassfish.external.arc;
28
29 /**
30 Taxonomy values.
31 See http://opensolaris.org/os/community/arc/policies/interface-taxonomy/
32 <p>
33 <h3>Policy</h3>
34 <ul>
35 <li>Applies to All software produced by SMI</li>
36 <li>Authority SAC</li>
37 <li>Approval SAC</li>
38 <li>Effective April, 1992</li>
39 <li>Policy </li>
40 <ul><li>All software interfaces must be classified according to this taxonomy.
41 Interfaces are defined as APIs, files and directory structures, file formats, protocols,
42 (sometimes) even performance and reliability behaviors, and any other attribute upon
43 which another component might reasonably depend.</li>
44
45 <li>An ARC must review, approve and archive the specification for all interfaces
46 other than Project Private and Internal. Unreviewed, unapproved interfaces are assumed
47 to be Internal. An adequate specification, suitable for archiving must exist for all
48 interfaces submitted for review. Often Project Private interfaces are also reviewed if
49 the presentation of them aids the understanding of the entire project or it is expected
50 they will be promoted to a broader classification in the future.</li>
51
52 <li>Adequate customer documentation must exist for all Public interfaces.
53 It is strongly preferred that manual pages exist for all Public interfaces
54 (supported on Solaris), even if only significant content of those pages are SYNOPSIS
55 and ATTRIBUTES sections and a textual pointer to other documentation.
56 Independent of the form of documentation delivery, the interface taxonomy commitment
57 level must be presented to the consumer.</li>
58
59 <li>In cases where the organization delivering the interface implementation does not
60 control the interface specification, the controlling body must be be clearly cited
61 in the documentation. In the case where a well-defined, versioned document is the
62 specification, both the name and precise version must be be cited.</li>
63 </ul>
64 </ul>
65 @author llc
66 */
67 public enum Stability {
68 /**
69 <pre>
70 +----------------------------------------------------------------------------+
71 | Committed (formerly Stable, Public; encompasses Standard, Evolving) |
72 |----------------------------------------------------------------------------|
73 | | Specification | Open |
74 | |---------------------+--------------------------------------------------|
75 | | Incompatible Change | major release (X.0) |
76 | |---------------------+--------------------------------------------------|
77 | | ARC review of Specs | Yes |
78 | |---------------------+--------------------------------------------------|
79 | | Examples | Compiler command line options, |
80 | | | hardware (SBus, PCI, USB), RPC, POSIX utilities |
81 +----------------------------------------------------------------------------+
82 </pre>
83 We publish the specification of these interfaces, typically as manual pages or other product documentation.
84 We also tell customers we will remain compatible with them. (Scott McNealy's principle that "Compatibility is a
85 constraint, not a goal") The intention of a Committed interface is to enable arbitrary third parties to develop
86 applications to these interfaces, release them, and have confidence that they will run on all releases of the product
87 after the one in which the interface was introduced, and within the same Major release. Even at a Major release,
88 incompatible changes are expected to be rare, and to have strong justifications.
89 <p>
90 Committed interfaces are often proposed to be industry standards, as was the case with RPC.
91 Also, interfaces defined and controlled as industry standards are most often treated as Committed interfaces.
92 <p>
93 These are interfaces whose specification is often under the provider's control or which are specified by a
94 clearly versioned document controlled by a well-defined organization. If the interface specification is not
95 under the implementation provider's control, the provider must be willing to fork from the interface specification
96 if required to maintain compatibility. In the case of interface specifications controlled by a standards body,
97 the commitment must be to a clearly identified version of the specification, minimizing the likelihood of an
98 incompatible change (but it can happen through formal spec interpretations).
99 <p>
100 Also, if the interface specification is not under the control of the interface implementation provider,
101 then the controlling body and/or public, versioned document must be be noted in the documentation.
102 This is particularly important for specifications controlled by recognized standards organizations.
103 <p>
104 Although a truely exceptional event, incompatible changes are possible in any release if
105 the associated defect is serious enough as outlined in the EXEMPTIONS section of this document or
106 in a Minor release by following the End of Feature process.
107 */
108 COMMITTED( "Committed" ),
109
110 /**
111 <pre>
112 +--------------------------------------------------------------------------+
113 | Uncommitted (formerly Unstable) |
114 |--------------------------------------------------------------------------|
115 | | Specification | Open |
116 | |---------------------+------------------------------------------------|
117 | | Incompatible Change | minor release (x.Y) with impact assessment |
118 | |---------------------+------------------------------------------------|
119 | | ARC review of Specs | Yes |
120 | |---------------------+------------------------------------------------|
121 | | Examples | SUNW* package abbreviations, some config utils |
122 +--------------------------------------------------------------------------+
123 </pre>
124 No guarantees are made about either source or binary compatibility of these interfaces
125 from one Minor release to the next. The most drastic incompatible change of removal of
126 the interface in a Minor release is allowed. Uncommitted interfaces are generally not
127 appropriate for use by release-independent products.
128 <p>
129 Uncommitted is not a license for gratuitous change. Any incompatible changes to the
130 interface should be motivated by true improvement to the interface which may include
131 justifiable ease of use considerations. The general expectation is that Uncommitted
132 interfaces are not likely to change incompatibly and if such changes occur they will be
133 small in impact and should often have a mitigation plan.
134 <p>
135 Uncommitted interfaces generally fall into one of the following subcategories:
136 <p>
137 <ul>
138 <li>
139 Interfaces that are experimental or transitional.
140 They are typically used to give outside developers early access to new or
141 rapidly-changing technology, or to provide an interim solution to a problem where a
142 more general solution is anticipated.
143 </li>
144
145 <li>
146 Interfaces whose specification is controlled by an outside body and the
147 implementation provider is only willing to commit to forking until the next minor
148 release point should that outside body introduce incompatible change.
149 Note that this "middle of the road" approach is often the best business decision
150 when the controlling body hasn't established a history of respecting compatibility.
151 </li>
152
153 <li>
154 Interfaces whose target audience values innovation (and possibly ease of use) over
155 stability. This attribute is often asserted for administrative interfaces for higher
156 web tier components. Note that ARC review may request data to support such an assertion.
157 </li>
158 <p>
159 A project's intention to import an Uncommitted interface from another consolidation should
160 be discussed with the ARC early. The stability classification of the interface -- or
161 a replacement interface -- might be raised. The opinion allowing any project to import an
162 Uncommitted interface must explain why it is acceptable, and a contract must be put into
163 place allowing this use. For Sun products, the similarity in the usage of Uncommitted and
164 Consolidation Private interfaces should be noted.
165 <p>
166 Any documentation for an Uncommitted interface must contain warnings that "these interfaces
167 are subject to change without warning and should not be used in unbundled products".
168 In some situations, it may be appropriate to document Uncommitted interfaces in white papers
169 rather than in standard product documentation. When changes are introduced, the changes
170 should be mentioned in the release notes for the affected release.
171 <p>
172 NOTE: If we choose to offer a draft standard implementation but state our intention to track
173 the standard (or the portions we find technically sound or likely to be standardized),
174 we set customer expectations for incompatible changes by classifying the interface Uncommitted.
175 The interface must be reclassified Committed when standard is final.
176 Such an intention could be encoded "Uncommitted->Committed".)
177 </pre>
178 */
179 UNCOMMITTED( "Uncommitted" ),
180
181
182 /**
183 <pre>
184 +--------------------------------------------------------------------+
185 | Volatile (encompasses External) |
186 |--------------------------------------------------------------------|
187 | | Specification | Open |
188 | |---------------------+------------------------------------------|
189 | | Incompatible Change | micro release (x.y.z) or patch release |
190 | |---------------------+------------------------------------------|
191 | | Arc review of Specs | A precise reference is normally recorded |
192 | |---------------------+------------------------------------------|
193 | | Examples | Gimp user interface, IETF internet-draft |
194 +--------------------------------------------------------------------+
195 </pre>
196 Volatile interfaces may change at any time and for any reason.
197 <p>
198 Use of the Volatile interface stability level allows interface providers to
199 quickly track a fluid, rapidly evolving specification. In many cases, this is
200 preferred to providing additional stability to the interface, as it may better
201 meet the expectations of the consumer.
202 <p>
203 The most common application of this taxonomy level is to interfaces that are
204 controlled by a body other than the final implementation provider, but unlike
205 specifications controlled by standards bodies or communities we place trust in,
206 it can not be asserted that an incompatible change to the interface
207 specification would be exceedingly rare. In some cases it may not even be
208 possible to clearly identify the controlling body. Although not prohibited by
209 this taxonomy, the Volatile classification is not typically applied to
210 interfaces where the specification is controlled by the implementation provider.
211 <p>
212 It should be noted that in some cases it will be preferable to apply a less
213 fluid interface classification to an interface even if the controlling body is
214 separate from the implementor. Use of the Uncommitted classification extends the
215 stability commitment over micro/patch releases, allowing use of additional
216 support models for software that depends upon these interfaces, at the potential
217 cost of less frequent updates. Committed should be considered for required, core
218 interfaces. If instability in the interface definition can't be reconciled with
219 the requirement for stability, then alternate solutions should be considered.
220 <p>
221 This classification is typically used for free or open source software (FOSS),
222 also referred to as community software, and similar models where it is deemed
223 more important to track the community with minimal latency than to provide
224 stability to our customers. When applying this classification level to community
225 software, particular attention should be paid to the considerations presented in
226 the preceding paragraph.
227 <p>
228 It also may be appropriate to apply the Volatile classification level to
229 interfaces in the process of being defined by trusted or widely accepted
230 organization. These are generically referred to as draft standards. An "IETF
231 internet draft" is a well understood example of a specification under
232 development.
233 <p>
234 There may also cases where Volatile is appropriate for experimental interfaces,
235 but in most cases Uncommitted should be considered first.
236 <p>
237 Irrespective of the control of the specification, the Volatile classification
238 must not be applied to "core" interfaces (those that must be used) for which no
239 alternate (and more stable) interface exists. Volatile interfaces must also
240 adhere to Sun internal standards in the following areas:
241 <ul>
242 <li>Security, Authentication</li>
243 <li>The existence of (perhaps vestigial) Manual Pages and conformance to Sun section numbering</li>
244 <li>File System Semantics (Solaris examples: /usr may be read-only, /var is where
245 all significant run-time growth occurs, ...)</li>
246 </ul>
247 All Volatile interfaces should be labeled as such in all associated
248 documentation and the consequence of using such interfaces must be explained
249 either as part of that documentation or by reference.
250 <p>
251 Shipping incompatible change in a patch should be strongly avoided. It is not
252 strictly prohibited for the following two reasons:
253 <ul>
254 <li>Since the patch provider may not be in explicit control of the changes to the
255 upstream implementation, it cannot guarantee with reasonable assurance that an
256 unidentified incompatibility is not present.
257 </li>
258 <li>A strong business case may exist for shipping a newer version as a patch if that
259 newer version closes significant escalations.
260 </li>
261 </ul>
262 In general, the intent of allowing change in a patch is to allow for change in
263 Update Releases.
264 <p>
265 Sun products should consider Volatile interfaces as equivalent to Consolidation
266 Private. A contract is required for use of these interfaces outside of the
267 supplying consolidation.
268 <p>
269 Extreme care in the use of Volatile interfaces is required by layered or
270 unbundled products. Layered products that depend upon Volatile interfaces must
271 include as part of their review material how they intend to manage the
272 dependency. It is not explicitly prohibited, but it is probable that unbundled
273 or layered products that ship asynchronously from the Volatile interfaces upon
274 which they depend will face nearly insurmountable difficulty in constructing a
275 plan to manage such a dependency.
276 */
277 VOLATILE( "Volatile" ),
278
279 /**
280 <pre>
281 +--------------------------------------------------------------------+
282 | Not-an-interface |
283 |--------------------------------------------------------------------|
284 | | Specification | None |
285 | |---------------------+------------------------------------------|
286 | | Incompatible Change | micro release (x.y.z) or patch release |
287 | |---------------------+------------------------------------------|
288 | | Arc review of Specs | None |
289 | |---------------------+------------------------------------------|
290 | | Examples | CLI output, error text |
291 +--------------------------------------------------------------------+
292 </pre>
293 In the course of reviewing or documenting interfaces, the situation often occurs
294 that an attribute will be present which may be inferred to be an interface, but
295 actually is not. A couple of common examples of this are output from CLIs
296 intended only for human consumption and the exact layout of a GUI.
297 <p>
298 This classification is simply a convenience term to be used to clarify such
299 situations where such confusion is identified as likely. Failure to apply this
300 term to an attribute is no indication that said attribute is some form of
301 interface. It only indicates that the potential for confusion was not
302 identified.
303 */
304 NOT_AN_INTERFACE( "Not-An-Interface" ),
305
306 /**
307 See: http://opensolaris.org/os/community/arc/policies/interface-taxonomy/
308 <p>
309 Javadoc or other means should establish the nature of the private interface.
310 */
311 PRIVATE( "Private" ),
312
313
314 /**
315 Not a formal term. Indicates that the interface, while visible, is experimental,
316 and can be removed at any time.
317 */
318 EXPERIMENTAL( "Experimental" ),
319
320 /**
321 Interrim classification; a real one should be chosen asap.
322 */
323 UNSPECIFIED( "Unspecified" );
324
325 private final String mName;
326 private Stability( final String name ) { mName = name; }
327
328 public String toString() { return mName; }
329 }