In Java how do you sort one list based on another? -


i've seen several other questions similiar 1 haven't been able find resolves problem.

my use case this: user has list of items (lista). reorder items , want persist order (listb), however, due restrictions i'm unable persist order on backend have sort lista after retrieve it.

so basically, have 2 arraylists (lista , listb). 1 specific order lists should in (listb) , other has list of items (lista). want sort lista based on listb.

collections.sort(listb, new comparator<item>() {     public int compare(item left, item right) {         return integer.compare(lista.indexof(left), lista.indexof(right));     } });

this quite inefficient, though, , should create map<item, integer> lista lookup positions of items faster.

guava has ready-to-use comparator doing that: ordering.explicit()


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