java - eclipse autogenerates !=null recursive calls -


given java code such as:

something v = a.getb().getc().getd().gete();

is there way in eclipse (templates or external plugins) generate safe chain call as:

if(a!=null &&     a.getb()!=null &&    a.getb().getc()!=null &&    a.getb().getc().getd()!=null &&            a.getb().getc().getd().gete()!=null){           v = a.getb().getc().getd().gete();     }

have given thought try{} catch(nullpointerexception e){} block? might feel less elegant, stop code if of method calls fails because previous 1 returned null, , give chance give default value if null.

another option this:

something v = /*default value*/ // overwritten if subsequent methods succeed. object temp = a.getb(); // use whatever object type getb() returns. if(temp != null){     temp = temp.getc();      /* if getc() returns different type of object,       * either use different variable or make temp variable broader       * (such generic object type) */     if(temp != null){         temp = temp.getd();         if(temp != null){             temp = temp.gete();             if(temp != null)                 v = temp;                  /* if previous calls returned substantial,                   * v useful */             }//if(gete() != null)         }//if(getd() != null)     }//if(getc() != null) }//if(getb() != null)

if want, use less cpu efficient, easier read, version not nesting if statements. if of if statements executed after eachother, single null prevent of next statements executing, although value still checked every time.

as far generating these statements, i'm not sure. depend on how far in advance can predict new methods available object returned previous method calls. if you're aiming auto-generation of code, might better off first suggestion: try-catch


Comments

Post a Comment

Popular posts from this blog

basic authentication with http post params android -

i doing basic authentication passing username , password , using basicnamevaluepair sending post params response service. my method: public stringbuilder callservicehttppost(string username, string password, string type) { // create new httpclient , post header httpclient httpclient = new defaulthttpclient(); httppost httppost = new httppost(webservice + type); httpresponse response = null; stringbuilder total = new stringbuilder(); try { url url = new url(webservice + type); /*string base64encodedcredentials = base64.encodetostring((username + ":" + password).getbytes(), base64.url_safe | base64.no_wrap);*/ string base64encodedcredentials = "basic " + base64.encodetostring( (username + ":" + password).getbytes(), base64.no_wrap); httppost.setheader("auth...
Read more

vb.net - Virtual Keyboard commands -

i wondering difference between virtual these keyboard commands is: keyeventf_extendedkey , keyeventf_keyup is. everywhere have looked gives me description based off integers , not want know each of them does. you've tagged question vb.net, these have nothing @ vb.net. they're constants defined in windows header files, use win32 api functions. as far difference, can't tell looking @ values. individual values not particularly important, that's why named identifiers used. what's important used , documentation functions tells mean. the first one, keyeventf_extendedkey , used keybdinput structure (which used along e.g. sendinput function) pass information synthesized keyboard input. if flag used, means scan code should interpreted extended key. technically, means scan code preceded prefix byte value 224 (&he0 in hexadecimal notation). the second one, keyeventf_keyup , 1 of flags available use structure. means key being released (going up)...
Read more

css - Firefox for ubuntu renders wrong colors -

Image
i've got following problem: i'm developing website, while testing around i've noticed firefox , chromium display css bar in different colors. when switched between several machine come conclusion firefox ubuntu problem. on other devices i've tested website. it's fine. the differences between chrome , firefox rendering: firefox: chromium: note: firefox ubuntu problem. does knows why , came solution? https://bugzilla.mozilla.org/show_bug.cgi?id=655637 bug 629312 - firefox displays wrong colors on image (only linux) open about:config , rechange gfx.color_management.mode 2 0.
Read more