java - Dependency Injection: Difference between loose coupling mechanisms based on interface and class? -


suppose, have 2 configurations.

first one:

interface {     ... }  class implements {     ... }  class b implements {     ... }  class component {     i;         component (i i) {         this.i = i;     } }

second one:

class c {     ... }  class extends c {     ... }  class b extends c {     ... }  class component {     c c;         component (c c) {         this.c = c;     } }

what in difference between 2 configurations using 2 different loose coupling mechanisms (based on interface , based on class)?

why should need use interface on class?

an object can implements multiple interfaces can extends 1 class, user of loose coupled library may not able extends class.

when extends, incorporate code of superclass yours, there no code incorporate implements better suited.

finally not same paradigm, when write "b extends a" "i a, same things, can make other things". when write "b implements a" "i b, can treat me a".

long story short, practical reason first.


-

Comments

Post a Comment

Popular posts from this blog

c# - Binding a comma separated list to a List<int> in asp.net web api -

the default binder in web api expecst http://url.com/webapi/report/?pageids=3243&pageids=2365 to bind public ihttpactionresult report(list<int> pageids){ // exciting webapi code} i wish bind http://url.com/webapi/report/?pageids=3243,2365 as running out of space in url get . i have created class public class commaseparatedmodelbinder : system.web.http.modelbinding.imodelbinder { public bool bindmodel(httpactioncontext actioncontext, modelbindingcontext bindingcontext) { //binding in here } } and registered in webapiconfig.cs var provider = new simplemodelbinderprovider( typeof(list<int>), new commaseparatedmodelbinder()); config.services.insert(typeof(modelbinderprovider), 0, provider); i have altered method signature use model binder so public ihttpactionresult report( [modelbinder] list<int> pageids){ // exciting webapi code} however break point in binder not being
Read more

Delphi 7 and decode UTF-8 base64 -

in delphi 7, have widestring encoded base64(that received web service widestring result) : pd94bwwgdmvyc2lvbj0ims4wij8+dqo8c3ryaw5nptiq2lpyqjwvc3ryaw5npg== when decoded it, result not utf-8: <?xml version="1.0"?> <string>طھط³طھ</string> but when decoded base64decode.org, result true : <?xml version="1.0"?> <string>تست</string> i have use encddecd unit decodestring function. the problem have using decodestring . function, in delphi 7, treats decoded binary data being ansi encoded. , problem text utf-8 encoded. to continue encddecd unit have couple of options. can switch decodestream . instance, code produce utf-8 encoded text file data: {$apptype console} uses classes, encddecd; const data = 'pd94bwwgdmvyc2lvbj0ims4wij8+dqo8c3ryaw5nptiq2lpyqjwvc3ryaw5npg=='; var input: tstringstream; output: tfilestream; begin input := tstringstream.create(data); try output := tfilestream.
Read more

html - Is there any way to exclude a single element from the style? (Bootstrap) -

so, have img logo, overlaid on div styled background-image: url("...") , , both elements inside 2 div classes .to-color , .to-overlay respectively, black transparent overlay. is there way exclude logo style given these 2 classes? here's jsfiddle example: link html , css example: - html - <div class="to-color"> <div class="to-overlay"> <div class="respo"> <div class="row"> <div class="col-xs-4 col-xs-offset-4 text-center"> <img src="http://ansonalex.com/wp-content/uploads/2011/06/google-logo-768x260.png" alt="..." class="img-responsive"> </div> </div> </div> </div> </div> - css - .to-color { background-color: #000; } .to-overlay { opacity : 0.5; } .respo { background-image: url("https://source.unsplash.com/category/objects/1600x900"); background-position: center center;
Read more