Re: DDD Implementation: Marker interfaces for all classes
"Paul Rayner [email protected] [domaindrivendesign]" <[email protected]> Sat, 13 Aug 2016 17:18:25 -0600
| Newsgroups | gmane.comp.programming.domain-driven-design |
|---|---|
| Message-ID | <CAKKp0qjzLL_yHRjHe7up7nnvox36tDzYi4uqo-zA=jixgcXPLg@mail.gmail.com> |
--001a114e3dd8ae7c640539fc396d Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable > To put this in perspective: People in this project are coming from a 4GL > background using a tool with very limited set of concepts/capabilities. T= he > new development platform is JEE. Now they are concerned that there will b= e > chaotic code structures and want to limit this by only allowing a defined > set of building blocks and no classes that do not conform to these buildi= ng > blocks. > I see this approach as being very problematic. The DDD building block patterns are *not* intended to be a complete list of object types for domain modeling. They are a set of useful domain modeling patterns that can help get your domain complexity under control by simplifying your domain model. There are other - better - ways to avoid chaotic code structures. > 2016-08-13 18:36 GMT+02:00 Paul Rayner [email protected] > [domaindrivendesign] <[email protected]>: > >> >> >> >> >> On Sat, Aug 13, 2016 at 12:28 AM, Niklas Mehner [email protected] >> [domaindrivendesign] <[email protected]> wrote: >> >>> >>> >>> Hello everyone, >>> >>> We are currently in a somewhat heated discussions about the design for = a >>> new software. >>> >>> One of the discussion points is the use of marker interfaces. >>> >>> I am perfectly fine with using marker interfaces like: >>> >>> SomeService implements DomainService { >>> ... >>> } >>> >>> to make the architecture visible in the code and implement some >>> verification of code properties. >>> >>> But now some people want to add the requirement to have assign each >>> class to a building block (Entity/Value Object/Service/...). >>> Has anybody ever successfully done this? Is this even possible without >>> some "GenericImplementationObject" building block? >>> >> >> Are you saying you want to have each class named according to its >> building block pattern name, or something like that? I can't think of an= y >> good reason to do this. The building block patterns are *not* the >> important concepts in your domain model, the ubiquitous language is. Foc= us >> *first* on the language of your domain model. The implementation >> patterns used to represent the concepts are secondary concerns. >> >> > >=20 > --001a114e3dd8ae7c640539fc396d Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable <head> <style type=3D"text/css"> <!-- /* start of attachment style */ .ygrp-photo-title{ clear: both; font-size: smaller; height: 15px; overflow: hidden; text-align: center; width: 75px; } div.ygrp-photo{ background-position: center; background-repeat: no-repeat; background-color: white; border: 1px solid black; height: 62px; width: 62px; } div.photo-title=20 a, div.photo-title a:active, div.photo-title a:hover, div.photo-title a:visited { text-decoration: none;=20 } div.attach-table div.attach-row { clear: both; } div.attach-table div.attach-row div { float: left; /* margin: 2px;*/ } p { clear: both; padding: 15px 0 3px 0; overflow: hidden; } div.ygrp-file { width: 30px; valign: middle; } div.attach-table div.attach-row div div a { text-decoration: none; } div.attach-table div.attach-row div div span { font-weight: normal; } div.ygrp-file-title { font-weight: bold; } /* end of attachment style */ --> </style> </head> <html> <head> <style type=3D"text/css"> <!-- #ygrp-mkp { border: 1px solid #d8d8d8; font-family: Arial; margin: 10px 0; padding: 0 10px; } #ygrp-mkp hr { border: 1px solid #d8d8d8; } #ygrp-mkp #hd { color: #628c2a; font-size: 85%; font-weight: 700; line-height: 122%; margin: 10px 0; } #ygrp-mkp #ads { margin-bottom: 10px; } #ygrp-mkp .ad { padding: 0 0; } #ygrp-mkp .ad p { margin: 0; } #ygrp-mkp .ad a { color: #0000ff; text-decoration: none; } --> </style> </head> <body> <!-- |**|begin egp html banner|**| --> <br><br> <!-- |**|end egp html banner|**| --> <div dir=3D"ltr"><div class=3D"gmail_extra"><div class=3D"gmail_quote"><div= >=C2=A0</div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;b= order-left:1px #ccc solid;padding-left:1ex"><div style=3D"background-color:= #fff"><div><div><div><div dir=3D"ltr"><div>To put this in perspective: Peop= le in this project are coming from a 4GL background using a tool with very = limited set of concepts/capabilities. The new development platform is JEE. = Now they are concerned that there will be chaotic code structures and want = to limit this by only allowing a defined set of building blocks and no clas= ses that do not conform to these building blocks. <br></div></div></div></d= iv></div></div></blockquote><div><br></div><div>I see this approach as bein= g very problematic. The DDD building block patterns are <i>not</i> intended= to be a complete list of object types for domain modeling. They are a set = of useful domain modeling patterns that can help get your domain complexity= under control by simplifying your domain model.</div><div><br></div><div>T= here are other - better - ways to avoid chaotic code structures.</div><div>= <br></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;bord= er-left:1px #ccc solid;padding-left:1ex"><div style=3D"background-color:#ff= f"><div><div><div><div dir=3D"ltr"><div><div class=3D"h5"><div><div><div><d= iv><br><div><div><div class=3D"gmail_extra"><div class=3D"gmail_quote">2016= -08-13 18:36 GMT+02:00 Paul Rayner <a href=3D"mailto:[email protected]= m" target=3D"_blank">[email protected]</a> [domaindrivendesign] <span= dir=3D"ltr"><<a href=3D"mailto:[email protected]" targ= et=3D"_blank">domaindrivendesign@<wbr>yahoogroups.com</a>></span>:<br><b= lockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-le= ft:1px solid rgb(204,204,204)"> <u></u> =20 <div style=3D"background-color:rgb(255,255,255)"> <span>=C2=A0</span> <div> <div> <div> =20=20=20=20=20=20 =20=20=20=20=20=20 <p></p><div dir=3D"ltr"><br><div class=3D"gmail_extra"><br><div class= =3D"gmail_quote"><span>On Sat, Aug 13, 2016 at 12:28 AM, Niklas Mehner <a h= ref=3D"mailto:[email protected]" target=3D"_blank">niklas.mehner@gmai= l.com</a> [domaindrivendesign] <span dir=3D"ltr"><<a href=3D"mailto:doma= [email protected]" target=3D"_blank">domaindrivendesign@yahoog= roup<wbr>s.com</a>></span> wrote:<br><blockquote class=3D"gmail_quote" s= tyle=3D"border-left:1px solid rgb(204,204,204)"> <u></u> =20 <div style=3D"background-color:rgb(255,255,255)"> <span>=C2=A0</span> <div> <div> <div> =20=20=20=20=20=20 =20=20=20=20=20=20 <p></p><div dir=3D"ltr"><div><div><div><div><div><div><div><div>Hello= everyone,<br><br></div>We are currently in a somewhat heated discussions a= bout the design for a new software.<br><br></div>One of the discussion poin= ts is the use of marker interfaces.<br><br></div>I am perfectly fine with u= sing marker interfaces like:<br><br></div>SomeService implements DomainServ= ice {<br>=C2=A0=C2=A0 ...<br>}<br><br></div><div>to make the architecture v= isible in the code and implement some verification of code properties.<br><= /div><div><br></div>But now some people want to add the requirement to have= assign each class to a building block (Entity/Value Object/Service/...).<b= r></div>Has anybody ever successfully done this? Is this even possible with= out some "GenericImplementationObject" building block?<br></div><= /div></div></div></div></div></div></blockquote><div><br></div></span><div>= Are you saying you want to have each class named according to its building = block pattern name, or something like that? I can't think of any good r= eason to do this. The building block patterns are <i>not</i> the important = concepts in your domain model, the ubiquitous language is. Focus <i>first</= i> on the language of your domain model. The implementation patterns used t= o represent the concepts are secondary concerns.</div></div></div></div> <p></p> </div> =20=20=20=20=20 =20=20=20=20 <div style=3D"color:rgb(255,255,255);min-height:0px"></div> </div> =20=20 </div></div></blockquote></div><br></div></div></div></div></div></div></di= v></div></div></div></div></div></div></div></blockquote><div><br></div><di= v>=C2=A0</div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;= border-left:1px #ccc solid;padding-left:1ex"><div style=3D"background-color= :#fff"><div><div><div><div dir=3D"ltr"><div><div class=3D"h5"><div><div><di= v><div><div><div><div class=3D"gmail_extra"></div></div></div></div></div><= /div></div></div></div></div> <p></p> </div><span class=3D""> =20=20=20=20=20 =20=20=20=20 <div style=3D"color:#fff;min-height:0"></div> </div> =20=20 </blockquote></div><br></div></div> <!-- |**|begin egp html banner|**| --> <br> <br> <!-- |**|end egp html banner|**| --> <div width=3D"1" style=3D"color: white; clear: both;"/>__._,_.___</div> =20=20=20=20=20=20 =20=20 =20=20=20=20 <div id=3D"fromDMARC" style=3D"clear:both; margin-top: 10px;"> <hr style=3D"height:2px ; border-width:0; color:#E3E3E3; backgroun= d-color:#E3E3E3;"> Posted by: Paul Rayner <[email protected]> <hr = style=3D"height:2px ; border-width:0; color:#E3E3E3; background-color:#E3E3= E3;"> </div> <!-- Start Recommendations --> <!-- End Recommendations --> <!-- |**|begin egp html banner|**| --> <img src=3D"http://geo.yahoo.com/serv?s=3D97476590/grpId=3D8116923/grpspI= d=3D1705007181/msgId=3D24790/stime=3D1471130349" width=3D"1" height=3D"1"> = <br> <!-- |**|end egp html banner|**| --> =20=20 <!-- |**|begin egp html banner|**| --> <br> =20=20=20 =20=20=20=20=20 =20 <!-- |**|begin egp html banner|**| --> <div id=3D"ygrp-vital" style=3D"background-color: #f2f2f2; font-fam= ily: Verdana; font-size: 10px; margin-bottom: 10px; padding: 10px;"> <span id=3D"vithd" style=3D"font-weight: bold; color: #333; text-tr= ansform: uppercase; "><a href=3D"https://groups.yahoo.com/neo/groups/domain= drivendesign/info;_ylc=3DX3oDMTJlbDc1bW1jBF9TAzk3MzU5NzE0BGdycElkAzgxMTY5Mj= MEZ3Jwc3BJZAMxNzA1MDA3MTgxBHNlYwN2dGwEc2xrA3ZnaHAEc3RpbWUDMTQ3MTEzMDM0OQ--"= style=3D"text-decoration: none;">Visit Your Group</a></span> <ul style=3D"list-style-type: none; margin: 0; padding: 0; display: in= line;"> <li style=3D"border-right: 1px solid #000; font-weight: 700; di= splay: inline; padding: 0 5px; margin-left: 0;"> <span class=3D"cat"><a href=3D"https://groups.yahoo.com/neo/groups/do= maindrivendesign/members/all;_ylc=3DX3oDMTJmaHYzMW9hBF9TAzk3MzU5NzE0BGdycEl= kAzgxMTY5MjMEZ3Jwc3BJZAMxNzA1MDA3MTgxBHNlYwN2dGwEc2xrA3ZtYnJzBHN0aW1lAzE0Nz= ExMzAzNDk-" style=3D"text-decoration: none;">New Members</a></span> <span class=3D"ct" style=3D"color: #ff7900;">2</span> </li> </ul> </div> <div id=3D"ft" style=3D"font-family: Arial; font-size: 11px; margin-top: 5p= x; padding: 0 2px 0 0; clear: both;"> <a href=3D"https://groups.yahoo.com/neo;_ylc=3DX3oDMTJkc2tkOHNyBF9TAzk3ND= c2NTkwBGdycElkAzgxMTY5MjMEZ3Jwc3BJZAMxNzA1MDA3MTgxBHNlYwNmdHIEc2xrA2dmcARzd= GltZQMxNDcxMTMwMzQ5" style=3D"float: left;"><img src=3D"http://l.yimg.com/r= u/static/images/yg/img/email/new_logo/logo-groups-137x15.png" height=3D"15"= width=3D"137" alt=3D"Yahoo! Groups" style=3D"border: 0;"/></a> <div style=3D"color: #747575; float: right;"> • <a href=3D"https://i= nfo.yahoo.com/privacy/us/yahoo/groups/details.html" style=3D"text-decoratio= n: none;">Privacy</a> • <a href=3D"mailto:domaindrivendesign-unsubscri= [email protected]?subject=3DUnsubscribe" style=3D"text-decoration: none;">= Unsubscribe</a> • <a href=3D"https://info.yahoo.com/legal/us/yahoo/uto= s/terms/" style=3D"text-decoration: none;">Terms of Use</a> </div> </div> <!-- |**|end egp html banner|**| --> </div> <!-- ygrp-msg --> =20=20=20 <br> <!-- |**|end egp html banner|**| --> <div style=3D"color: white; clear: both;"/>__,_._,___</div> </body> </html> --001a114e3dd8ae7c640539fc396d--