http://wiki.apidesign.org/index.php?title=Final_interface&action=history Revision history for this page on the wiki en MediaWiki 1.12.0rc1 Sun, 12 Apr 2026 19:14:17 GMT http://wiki.apidesign.org/index.php?title=Final_interface&diff=10285&oldid=prev <p><span class="autocomment">JDK: Scratching Own Itch!</span></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr> <td colspan='2' style="background-color: white; color:black;">←Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 06:00, 30 September 2020</td> </tr> <tr><td colspan="2" class="diff-lineno">Line 19:</td> <td colspan="2" class="diff-lineno">Line 19:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>It may seem most of this discussion is obsolete with [[JDK]]8 [[DefaultMethods]]. With [[JDK]]8 you can add new methods with ''default implementations'' into existing interfaces - which is then mostly compatible extension (however only mostly, read [[BinaryCompatibleDefaultMethods]] for more horror stories about [[DefaultMethods]] - there is no free lunch!). Reasonable [[API]] writers then provide the default bodies for newly added methods and mitigate most of the [[DOM]]2 vs. [[DOM]]3 problems by that.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>It may seem most of this discussion is obsolete with [[JDK]]8 [[DefaultMethods]]. With [[JDK]]8 you can add new methods with ''default implementations'' into existing interfaces - which is then mostly compatible extension (however only mostly, read [[BinaryCompatibleDefaultMethods]] for more horror stories about [[DefaultMethods]] - there is no free lunch!). Reasonable [[API]] writers then provide the default bodies for newly added methods and mitigate most of the [[DOM]]2 vs. [[DOM]]3 problems by that.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>It is however interesting to analyze the reasons why ''extender methods'' were introduced. Of course, people we crying for them for ages, but the members of [[JDK]] team were refusing all such efforts. Why? To keep the purity of the language (correct as [[DefaultMethods]] decrease [[clarity]] of the [[<del style="color: red; font-weight: bold; text-decoration: none;">provider</del>]] interface).</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>It is however interesting to analyze the reasons why ''extender methods'' were introduced. Of course, people we crying for them for ages, but the members of [[JDK]] team were refusing all such efforts. Why? To keep the purity of the language (correct as [[DefaultMethods]] decrease [[clarity]] of the [[<ins style="color: red; font-weight: bold; text-decoration: none;">ProviderAPI</ins>]] interface).</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>However when they finally felt all the pain - e.g. when the {{JDK|java/util|Collection}} and etc. interfaces were found insufficient, they immediately changed their mind. And of course, because they control the [[VM]], they could do (unlike us, regular outsider beings) miracles. It is way easier to resolve [[backward compatibility]] issues if you control the way linkage is done! </div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>However when they finally felt all the pain - e.g. when the {{JDK|java/util|Collection}} and etc. interfaces were found insufficient, they immediately changed their mind. And of course, because they control the [[VM]], they could do (unlike us, regular outsider beings) miracles. It is way easier to resolve [[backward compatibility]] issues if you control the way linkage is done! </div></td></tr> </table> Wed, 30 Sep 2020 06:00:48 GMT JaroslavTulach http://wiki.apidesign.org/wiki/Talk:Final_interface http://wiki.apidesign.org/index.php?title=Final_interface&diff=10284&oldid=prev <p><span class="autocomment">JDK: Scratching Own Itch!</span></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr> <td colspan='2' style="background-color: white; color:black;">←Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 06:00, 30 September 2020</td> </tr> <tr><td colspan="2" class="diff-lineno">Line 17:</td> <td colspan="2" class="diff-lineno">Line 17:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== [[JDK]]: Scratching Own Itch! ==</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== [[JDK]]: Scratching Own Itch! ==</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">Of course </del>most of this discussion is <del style="color: red; font-weight: bold; text-decoration: none;">becoming </del>obsolete with [[JDK]]8 <del style="color: red; font-weight: bold; text-decoration: none;">extender methods</del>. With [[JDK]]8 you can add new methods with ''default implementations'' into existing interfaces - which is then <del style="color: red; font-weight: bold; text-decoration: none;">source and binary </del>compatible extension. Reasonable [[API]] writers <del style="color: red; font-weight: bold; text-decoration: none;">will </del>then provide the default bodies for newly added methods and mitigate the [[DOM]]2 vs. [[DOM]]3 problems by that.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">It may seem </ins>most of this discussion is obsolete with [[JDK]]8 <ins style="color: red; font-weight: bold; text-decoration: none;">[[DefaultMethods]]</ins>. With [[JDK]]8 you can add new methods with ''default implementations'' into existing interfaces - which is then <ins style="color: red; font-weight: bold; text-decoration: none;">mostly </ins>compatible extension <ins style="color: red; font-weight: bold; text-decoration: none;">(however only mostly, read [[BinaryCompatibleDefaultMethods]] for more horror stories about [[DefaultMethods]] - there is no free lunch!)</ins>. Reasonable [[API]] writers then provide the default bodies for newly added methods and mitigate <ins style="color: red; font-weight: bold; text-decoration: none;">most of </ins>the [[DOM]]2 vs. [[DOM]]3 problems by that.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>It is however interesting to analyze the reasons why ''extender methods'' were introduced. Of course, people we crying for them for ages, but the members of [[JDK]] team were refusing all such efforts. Why? To keep the purity of the language.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>It is however interesting to analyze the reasons why ''extender methods'' were introduced. Of course, people we crying for them for ages, but the members of [[JDK]] team were refusing all such efforts. Why? To keep the purity of the language <ins style="color: red; font-weight: bold; text-decoration: none;">(correct as [[DefaultMethods]] decrease [[clarity]] of the [[provider]] interface)</ins>.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>However when they finally felt all the pain - e.g. when the {{JDK|java/util|Collection}} and etc. interfaces were found insufficient, they immediately changed their mind. And of course, because they control the [[VM]], they could do (unlike us, regular outsider beings) miracles. It is way easier to resolve [[backward compatibility]] issues if you control the way linkage is done! </div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>However when they finally felt all the pain - e.g. when the {{JDK|java/util|Collection}} and etc. interfaces were found insufficient, they immediately changed their mind. And of course, because they control the [[VM]], they could do (unlike us, regular outsider beings) miracles. It is way easier to resolve [[backward compatibility]] issues if you control the way linkage is done! </div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>All that is needed is to motivate owner of [[HotSpot]] to implement some small enhancement. That however requires the owner to feel the pain - e.g. simulate common problem in context of [[JDK]] - that is however tough - [[JDK]] is specific isolated project and problems they face are often too different from real world ones. But when a rare situation happens (e.g. [[JDK]] feels the same problem as rest of the world), ''scratching own itch'' can really move things forward!</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>All that is needed is to motivate owner of [[HotSpot]] to implement some small enhancement. That however requires the owner to feel the pain - e.g. simulate common problem in context of [[JDK]] - that is however tough - [[JDK]] is specific isolated project and problems they face are often too different from real world ones. But when a rare situation happens (e.g. [[JDK]] feels the same problem as <ins style="color: red; font-weight: bold; text-decoration: none;">the </ins>rest of the world), ''scratching own itch'' can really move things forward!</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== Enforcing [[final interface]] During Compilation ==</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== Enforcing [[final interface]] During Compilation ==</div></td></tr> </table> Wed, 30 Sep 2020 06:00:28 GMT JaroslavTulach http://wiki.apidesign.org/wiki/Talk:Final_interface http://wiki.apidesign.org/index.php?title=Final_interface&diff=8198&oldid=prev <p><span class="autocomment">Enforcing final interface During Compilation</span></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr> <td colspan='2' style="background-color: white; color:black;">←Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 16:59, 4 February 2015</td> </tr> <tr><td colspan="2" class="diff-lineno">Line 27:</td> <td colspan="2" class="diff-lineno">Line 27:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== Enforcing [[final interface]] During Compilation ==</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== Enforcing [[final interface]] During Compilation ==</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>There is a way to turn the ''don't implement me, please'' [[Javadoc]] warning into something real, that will open eyes of everyone who tries to implement a [[final interface]]. There is a way to fail one's build in case of violation of the advice! The check can be done with a simple [[AnnotationProcessor]]. When you have your [[final interface]]:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>There is a way to turn the ''don't implement me, please'' [[Javadoc]] warning into something real, <ins style="color: red; font-weight: bold; text-decoration: none;">something </ins>that will open eyes of everyone who tries to implement a [[final interface]]. There is a way to fail one's build in case of violation of the advice! The check can be done with a simple [[AnnotationProcessor]]. When you have your [[final interface]]:</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>&lt;source lang=&quot;java&quot;&gt;</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>&lt;source lang=&quot;java&quot;&gt;</div></td></tr> </table> Wed, 04 Feb 2015 16:59:31 GMT JaroslavTulach http://wiki.apidesign.org/wiki/Talk:Final_interface http://wiki.apidesign.org/index.php?title=Final_interface&diff=8197&oldid=prev <p><span class="autocomment">Enforcing final interface During Compilation</span></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr> <td colspan='2' style="background-color: white; color:black;">←Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 16:58, 4 February 2015</td> </tr> <tr><td colspan="2" class="diff-lineno">Line 87:</td> <td colspan="2" class="diff-lineno">Line 87:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>&lt;/source&gt;</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>&lt;/source&gt;</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>A compile check of this kind makes the [[API Design]]er in me way more happier! Users of your [[API]] <del style="color: red; font-weight: bold; text-decoration: none;">are </del>may be [[clueless]] (as I always claim) and may not bother reading documentation, but none of them can ignore failing build!</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>A compile check of this kind makes the [[API Design]]er in me way more happier! Users of your [[API]] may be [[clueless]] (as I always claim) and may not bother reading documentation, but none of them can ignore failing build!</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>A [[final interface]] accompanied by an [[AnnotationProcessor]] is finally real [[:Category:APIDesignPatterns|API Design Pattern]]!</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>A [[final interface]] accompanied by an [[AnnotationProcessor]] is finally real [[:Category:APIDesignPatterns|API Design Pattern]]!</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[[Category:APIDesignPatterns]] [[Category:APIDesignPatterns:Anti]] [[Category:APIDesignPatterns:Evolution]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[[Category:APIDesignPatterns]] [[Category:APIDesignPatterns:Anti]] [[Category:APIDesignPatterns:Evolution]]</div></td></tr> </table> Wed, 04 Feb 2015 16:58:04 GMT JaroslavTulach http://wiki.apidesign.org/wiki/Talk:Final_interface http://wiki.apidesign.org/index.php?title=Final_interface&diff=8196&oldid=prev <p><span class="autocomment">Enforcing final interface During Compilation</span></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr> <td colspan='2' style="background-color: white; color:black;">←Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 16:56, 4 February 2015</td> </tr> <tr><td colspan="2" class="diff-lineno">Line 68:</td> <td colspan="2" class="diff-lineno">Line 68:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> TypeElement te = (TypeElement) e;</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> TypeElement te = (TypeElement) e;</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>/* exception for the only known implementation:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>/* exception for the only known implementation:</div></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>if (&quot;org.apidesign.demo.finalinterface.AllowedImplementationTest&quot;.equals(te.getQualifiedName().toString())) continue;</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>if (&quot;org.apidesign.demo.finalinterface.AllowedImplementationTest&quot;.equals(</div></td></tr> <tr><td colspan="2">&nbsp;</td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"> </ins>te.getQualifiedName().toString())</div></td></tr> <tr><td colspan="2">&nbsp;</td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>) continue;</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>*/</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>*/</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> for (TypeMirror m : te.getInterfaces()) {</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> for (TypeMirror m : te.getInterfaces()) {</div></td></tr> </table> Wed, 04 Feb 2015 16:56:47 GMT JaroslavTulach http://wiki.apidesign.org/wiki/Talk:Final_interface http://wiki.apidesign.org/index.php?title=Final_interface&diff=8195&oldid=prev <p><span class="autocomment">Enforcing final interface During Compilation</span></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr> <td colspan='2' style="background-color: white; color:black;">←Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 16:56, 4 February 2015</td> </tr> <tr><td colspan="2" class="diff-lineno">Line 67:</td> <td colspan="2" class="diff-lineno">Line 67:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> if (e instanceof TypeElement) {</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> if (e instanceof TypeElement) {</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> TypeElement te = (TypeElement) e;</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> TypeElement te = (TypeElement) e;</div></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;"> </del>if (&quot;org.apidesign.demo.finalinterface.AllowedImplementationTest&quot;.equals(te.getQualifiedName().toString())) <del style="color: red; font-weight: bold; text-decoration: none;">{</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">/* exception for the only known implementation:</ins></div></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;"> </del>continue;</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>if (&quot;org.apidesign.demo.finalinterface.AllowedImplementationTest&quot;.equals(te.getQualifiedName().toString())) continue;</div></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;"> }</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">*/</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> for (TypeMirror m : te.getInterfaces()) {</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> for (TypeMirror m : te.getInterfaces()) {</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> if (FinalInterface.class.getName().equals(m.toString())) {</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> if (FinalInterface.class.getName().equals(m.toString())) {</div></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div> processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, &quot;Cannot implement FinalInterface&quot;, e);</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div> processingEnv.getMessager().printMessage(</div></td></tr> <tr><td colspan="2">&nbsp;</td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"> </ins>Diagnostic.Kind.ERROR, &quot;Cannot implement FinalInterface&quot;, e</div></td></tr> <tr><td colspan="2">&nbsp;</td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"> </ins>);</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> }</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> }</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> }</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div> }</div></td></tr> </table> Wed, 04 Feb 2015 16:56:06 GMT JaroslavTulach http://wiki.apidesign.org/wiki/Talk:Final_interface http://wiki.apidesign.org/index.php?title=Final_interface&diff=8192&oldid=prev <p><span class="autocomment">Enforcing final interface During Compilation</span></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr> <td colspan='2' style="background-color: white; color:black;">←Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 16:46, 4 February 2015</td> </tr> <tr><td colspan="2" class="diff-lineno">Line 83:</td> <td colspan="2" class="diff-lineno">Line 83:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>&lt;/source&gt;</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>&lt;/source&gt;</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>A compile check of this kind <del style="color: red; font-weight: bold; text-decoration: none;">make </del>the [[API Design]]er in me way more happier! Users of your [[API]] are <del style="color: red; font-weight: bold; text-decoration: none;">going to </del>be [[clueless]] (as I always claim) and <del style="color: red; font-weight: bold; text-decoration: none;">will </del>not bother reading documentation, but none of them ignore failing build!</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>A compile check of this kind <ins style="color: red; font-weight: bold; text-decoration: none;">makes </ins>the [[API Design]]er in me way more happier! Users of your [[API]] are <ins style="color: red; font-weight: bold; text-decoration: none;">may </ins>be [[clueless]] (as I always claim) and <ins style="color: red; font-weight: bold; text-decoration: none;">may </ins>not bother reading documentation, but none of them <ins style="color: red; font-weight: bold; text-decoration: none;">can </ins>ignore failing build!</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>A [[final interface]] accompanied by an [[AnnotationProcessor]] is finally real [[:Category:APIDesignPatterns|API Design Pattern]]!</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>A [[final interface]] accompanied by an [[AnnotationProcessor]] is finally real [[:Category:APIDesignPatterns|API Design Pattern]]!</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[[Category:APIDesignPatterns]] [[Category:APIDesignPatterns:Anti]] [[Category:APIDesignPatterns:Evolution]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[[Category:APIDesignPatterns]] [[Category:APIDesignPatterns:Anti]] [[Category:APIDesignPatterns:Evolution]]</div></td></tr> </table> Wed, 04 Feb 2015 16:46:43 GMT JaroslavTulach http://wiki.apidesign.org/wiki/Talk:Final_interface http://wiki.apidesign.org/index.php?title=Final_interface&diff=8191&oldid=prev <p><span class="autocomment">JDK: Scratching Own Itch!</span></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr> <td colspan='2' style="background-color: white; color:black;">←Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 16:44, 4 February 2015</td> </tr> <tr><td colspan="2" class="diff-lineno">Line 23:</td> <td colspan="2" class="diff-lineno">Line 23:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>However when they finally felt all the pain - e.g. when the {{JDK|java/util|Collection}} and etc. interfaces were found insufficient, they immediately changed their mind. And of course, because they control the [[VM]], they could do (unlike us, regular outsider beings) miracles. It is way easier to resolve [[backward compatibility]] issues if you control the way linkage is done! </div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>However when they finally felt all the pain - e.g. when the {{JDK|java/util|Collection}} and etc. interfaces were found insufficient, they immediately changed their mind. And of course, because they control the [[VM]], they could do (unlike us, regular outsider beings) miracles. It is way easier to resolve [[backward compatibility]] issues if you control the way linkage is done! </div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>All that is needed is to motivate owner of [[HotSpot]] to implement some small enhancement. That however requires the owner to feel the pain - e.g. simulate common problem in context of [[JDK]] - that is however tough - [[JDK]] is specific isolated project and problems they face are often too different from real world ones. But when a rare situation happens (e.g. [[JDK]] feels the problem as rest of the world), ''scratching own itch'' can really move things forward!</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>All that is needed is to motivate owner of [[HotSpot]] to implement some small enhancement. That however requires the owner to feel the pain - e.g. simulate common problem in context of [[JDK]] - that is however tough - [[JDK]] is specific isolated project and problems they face are often too different from real world ones. But when a rare situation happens (e.g. [[JDK]] feels the <ins style="color: red; font-weight: bold; text-decoration: none;">same </ins>problem as rest of the world), ''scratching own itch'' can really move things forward!</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== Enforcing [[final interface]] During Compilation ==</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== Enforcing [[final interface]] During Compilation ==</div></td></tr> </table> Wed, 04 Feb 2015 16:44:55 GMT JaroslavTulach http://wiki.apidesign.org/wiki/Talk:Final_interface http://wiki.apidesign.org/index.php?title=Final_interface&diff=8190&oldid=prev <p><span class="autocomment">JDK: Scratching Own Itch!</span></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr> <td colspan='2' style="background-color: white; color:black;">←Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 16:43, 4 February 2015</td> </tr> <tr><td colspan="2" class="diff-lineno">Line 19:</td> <td colspan="2" class="diff-lineno">Line 19:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Of course most of this discussion is becoming obsolete with [[JDK]]8 extender methods. With [[JDK]]8 you can add new methods with ''default implementations'' into existing interfaces - which is then source and binary compatible extension. Reasonable [[API]] writers will then provide the default bodies for newly added methods and mitigate the [[DOM]]2 vs. [[DOM]]3 problems by that.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Of course most of this discussion is becoming obsolete with [[JDK]]8 extender methods. With [[JDK]]8 you can add new methods with ''default implementations'' into existing interfaces - which is then source and binary compatible extension. Reasonable [[API]] writers will then provide the default bodies for newly added methods and mitigate the [[DOM]]2 vs. [[DOM]]3 problems by that.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>It is however interesting <del style="color: red; font-weight: bold; text-decoration: none;">the </del>analyze the reasons why ''extender methods'' were introduced. Of course, people we crying for them for ages, but the members of [[JDK]] team were refusing all such efforts. Why? To keep the purity of the language.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>It is however interesting <ins style="color: red; font-weight: bold; text-decoration: none;">to </ins>analyze the reasons why ''extender methods'' were introduced. Of course, people we crying for them for ages, but the members of [[JDK]] team were refusing all such efforts. Why? To keep the purity of the language.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>However when they finally felt all the pain - e.g. when the {{JDK|java/util|Collection}} and etc. interfaces were found insufficient, they immediately changed their mind. And of course, because they control the [[VM]], they could do (unlike us, regular outsider beings) miracles. It is way easier to resolve [[backward compatibility]] issues if you control the way linkage is done! </div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>However when they finally felt all the pain - e.g. when the {{JDK|java/util|Collection}} and etc. interfaces were found insufficient, they immediately changed their mind. And of course, because they control the [[VM]], they could do (unlike us, regular outsider beings) miracles. It is way easier to resolve [[backward compatibility]] issues if you control the way linkage is done! </div></td></tr> </table> Wed, 04 Feb 2015 16:43:13 GMT JaroslavTulach http://wiki.apidesign.org/wiki/Talk:Final_interface http://wiki.apidesign.org/index.php?title=Final_interface&diff=8189&oldid=prev <p><span class="autocomment">When it works?</span></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr> <td colspan='2' style="background-color: white; color:black;">←Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 16:42, 4 February 2015</td> </tr> <tr><td colspan="2" class="diff-lineno">Line 13:</td> <td colspan="2" class="diff-lineno">Line 13:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The above problems can be slightly mitigated if one has good runtime support for [[modularity]] and this may be the reason why the [[vendor library]] seems to be very popular in [[OSGi]] world. If the [[RangeDependencies|version range]] used by clients is wider than [[RangeDependencies|version range]] used by implementations proper versioning is possible and the [[OSGi]] container can select the right modules to compose a working system. More about this in the [[proximity]] essay. However it needs to be stated that this works only in [[vendor library|One to Many]] and in [[Semantic versioning|Few to Many]] mode - e.g. when there is a single provider (or few of them) of the [[DOM]] parser and many users of the [[DOM]] parsing API. Then one can use [[OSGi]] [[RangeDependencies]] to make sure the implementation has closer [[proximity]] than users of the [[DOM]] [[API]]. </div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The above problems can be slightly mitigated if one has good runtime support for [[modularity]] and this may be the reason why the [[vendor library]] seems to be very popular in [[OSGi]] world. If the [[RangeDependencies|version range]] used by clients is wider than [[RangeDependencies|version range]] used by implementations proper versioning is possible and the [[OSGi]] container can select the right modules to compose a working system. More about this in the [[proximity]] essay. However it needs to be stated that this works only in [[vendor library|One to Many]] and in [[Semantic versioning|Few to Many]] mode - e.g. when there is a single provider (or few of them) of the [[DOM]] parser and many users of the [[DOM]] parsing API. Then one can use [[OSGi]] [[RangeDependencies]] to make sure the implementation has closer [[proximity]] than users of the [[DOM]] [[API]]. </div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Once you end up with multiple [[DOM]] parser implementations in your application (like [[NetBeans]] - a large and [[modular]] application - did) - e.g. you enter [[modular library|Many to Many]] relationship, no close [[proximity]] is going to save you. The only saving point is to adhere to best [[API Design]] practice and separate [[ClientAPI]] from [[ProviderAPI]]s. As such [[I]] am going to include [[final interface]] in [[API Design]] anti patterns although [[I]] am sure [[OSGi]] friends will never try to understand <del style="color: red; font-weight: bold; text-decoration: none;">the </del>[[ClarityOfTypes|better alternative]].</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Once you end up with multiple [[DOM]] parser implementations in your application (like [[NetBeans]] - a large and [[modular]] application - did) - e.g. you enter [[modular library|Many to Many]] relationship, no close [[proximity]] is going to save you. The only saving point is to adhere to best [[API Design]] practice and separate [[ClientAPI]] from [[ProviderAPI]]s. As such [[I]] am going to include [[final interface]] in [[API Design]] anti patterns although [[I]] am sure [[OSGi]] friends will never try to understand <ins style="color: red; font-weight: bold; text-decoration: none;">such </ins>[[ClarityOfTypes|better alternative<ins style="color: red; font-weight: bold; text-decoration: none;">]] and stick to their [[proximity|own old guns</ins>]].</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== [[JDK]]: Scratching Own Itch! ==</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== [[JDK]]: Scratching Own Itch! ==</div></td></tr> </table> Wed, 04 Feb 2015 16:42:26 GMT JaroslavTulach http://wiki.apidesign.org/wiki/Talk:Final_interface