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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). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 27package 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 */ 67public 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} 330