java - How to make JAXB call the setter AFTER adding Elements to an List? -

i have data in xml-file want unmarshal jaxb myhashmap. myobject has string name, key in hashmap.

to prevent writing key/name information twice xml-file (once name of myobject , once key of myhashmap), added setter , getter arraylist, add/read data into/out of myhashmap.

@xmlrootelement public class myhashmap extends hashmap<string, myobject> implements serializable {      public myhashmap() {         super();     }      @xmlelement(name = "myobject")     public void setmyobjectsarraylist(arraylist<myobject> myobjectlist) {         (myobject myobject : myobjectlist) {             this.put(myobject.getname(), myobject);         }     }      public arraylist<myobject> getmyobjectsarraylist() {         if (this.isempty()) { // added setter called             return null;         }         arraylist<myobject> myobjectlist = new arraylist<myobject>();         myobjectlist.addall(this.values());         return myobjectlist;     } } 

it worked fine in java 7 (according andswer of this because of bug ), doesnt in java 8. in java 8 jaxb gets listobject , adds elemts instead of using setter.

so added "return null" if list empty. apparently jaxb sets empty list , adds elements afterwards not work code. there possibility tell jaxb add elements list , call setter then?

you can use map jaxb marshal , unmarshal it. (cf. https://jaxb.java.net/tutorial/section_6_2_1-a-survey-of-jaxb-annotations.html) avoid repetition of name, annotate @xmltransient in myobject.

another approach use adapter; you'd have wrap map parent element. see https://jaxb.java.net/tutorial/section_6_2_9-type-adapters-xmljavatypeadapter.html

yet possibility use simpler approach different implementation of root element class. let use myhashmap map , avoids dirty tricks, although accessors little more inconvenient call. of course, may implement map , clean and convenient, that's more code write.

@xmlrootelement public class myhashmap {     private boolean dirty = false;     private map<string,myobject> str2obj;     private list<myobject> myobjects = new arraylist<>();      @xmlelement(name = "myobject")     list<myobject> getmyobjects(){         dirty = true;         return myobjects();     }      // variant 1: expose str2obj     @xmltransient     public map<string,myobject> getstr2obj(){         if( dirty ) rebuild();         return str2obj;     }      private void rebuild(){         str2obj.clear();         for( myobject myobject: myobjects ){             str2obj.put(mmyobject.getname(), myobject );         }         dirty = false;     }      // variant 2: delegate put, get, , other methods     // use same approach }