public void printPair( P\u0101ris<String, Long><\/span> <\/b> p\u0101ris) {<\/tt>
\n \u00a0 System.out.println(\"(\"+pair.getFirst()+\",\"+pair.getSecond()+\")\");<\/tt>
\n }<\/tt> P\u0101ris<String, Long><\/span> <\/b> limits = jauns P\u0101ris<String, Long><\/span> <\/b> (\"maksimums\", 1024L);<\/tt>
\n printPair(limit);<\/tt><\/p><\/blockquote>\nPiem\u0113rs (aizst\u0101j\u0113jz\u012bmes parametriz\u0113tam tipam):<\/p>\n
\n public void printPair( Pair<?,?><\/span> <\/b> p\u0101ris) {<\/tt>
\n \u00a0 System.out.println(\"(\"+pair.getFirst()+\",\"+pair.getSecond()+\")\");<\/tt>
\n }<\/tt> Pair<?,?><\/span> <\/b> limits = jauns P\u0101ris<String, Long><\/span> <\/b> (\"maksimums\", 1024L);<\/tt>
\n printPair(limit);<\/tt><\/p><\/blockquote>\n<\/blockquote>\nVis\u0101m visp\u0101r\u012bg\u0101 tipa instanc\u0113m ir viens un tas pats izpildlaika tipa att\u0113lojums, proti, neapstr\u0101d\u0101t\u0101 tipa att\u0113lojums. Piem\u0113ram, visp\u0101r\u0113ja veida instancijas Saraksts<\/tt> , piem\u0113ram, Saraksts<Datums><\/tt> , Saraksts<String><\/tt> , Saraksts<Long><\/tt> uc ir da\u017e\u0101di statiskie tipi kompil\u0113\u0161anas laik\u0101, bet viens un tas pats dinamiskais tips Saraksts <\/tt> izpildlaik\u0101.<\/p>\n
Aktieris sast\u0101v no div\u0101m da\u013c\u0101m:<\/p>\n
\n- statisk\u0101 tipa p\u0101rbaude, ko kompilators veic kompil\u0113\u0161anas laik\u0101 un<\/li>\n
- dinamiska tipa p\u0101rbaude, ko izpildes laik\u0101 veic virtu\u0101l\u0101 ma\u0161\u012bna.<\/li>\n<\/ul>\n
Statisk\u0101 da\u013ca iz\u0161\u0137ir nej\u0113dz\u012bgus metienus, kas nevar izdoties, piem\u0113ram, cast no St\u012bga<\/tt> ka Datums<\/tt> vai no Saraksts<String><\/tt> ka Saraksts<Datums><\/tt> .<\/p>\n
Dinamisk\u0101 da\u013ca izmanto izpildlaika tipa inform\u0101ciju un izpildes laik\u0101 veic tipa p\u0101rbaudi.\u00a0 Tas paaugstina a ClassCastException<\/tt> ja objekta dinamiskais tips nav cast m\u0113r\u0137a tips (vai m\u0113r\u0137a tipa apak\u0161tips). Metienu piem\u0113ri ar dinamisko da\u013cu ir cast no Objekts<\/tt> ka St\u012bga<\/tt> vai no Objekts<\/tt> ka Saraksts<String><\/tt> .\u00a0 Tie ir t\u0101 sauktie downcasts, s\u0101kot no supertipa l\u012bdz apak\u0161tipam.<\/p>\n
Konkr\u0113tu parametriz\u0113tu tipu piem\u0113ri ir Saraksts<String><\/tt> , Karte<String,Datums><\/tt> , bet ne List<? pagarina Number><\/tt> vai Map<String,?><\/tt> .<\/p>\n
Da\u017ereiz tiek sagaid\u012bts, ka a Saraksts<Object><\/tt> b\u016btu supertips a Saraksts<String><\/tt> , jo Objekts<\/tt> ir supertips St\u012bga<\/tt> .\u00a0 \u0160\u012bs cer\u012bbas izriet no fakta, ka mas\u012bviem past\u0101v \u0161\u0101da veida attiec\u012bbas:\u00a0 Objekts[]<\/tt> ir supertips virkne[]<\/tt> , jo Objekts<\/tt> ir supertips St\u012bga<\/tt> . (\u0160\u0101da veida attiec\u012bbas ir paz\u012bstamas k\u0101 kovari\u0101cija<\/i> .) Komponentu tipu super-apak\u0161tipu attiec\u012bbas izv\u0113r\u0161as l\u012bdz atbilsto\u0161ajiem mas\u012bvu veidiem. \u0160\u0101da veida attiec\u012bbas nepast\u0101v visp\u0101r\u012bgu tipu instanc\u0113m. (Parametru veidi ir n\u0113<\/i> kovariants.)<\/p>\n
Super-apak\u0161tipu attiec\u012bbu tr\u016bkumam starp viena un t\u0101 pa\u0161a visp\u0101r\u012bg\u0101 tipa instanc\u0113m ir da\u017e\u0101das sekas.\u00a0 \u0160eit ir piem\u0113rs.<\/p>\n
Piem\u0113rs:<\/p>\n
void printAll(ArrayList<Object> c) {<\/tt>
\n \u00a0 priek\u0161 (Objekts : c)\u00a0<\/tt>
\n \u00a0\u00a0\u00a0 System.out.println(o);<\/tt>
\n }<\/tt> ArrayList<String> saraksts = new ArrayList<String>();<\/tt>
\n ... aizpild\u012bt sarakstu ...<\/tt>
\n druk\u0101tVisu(saraksts);\u00a0\u00a0 \/\/ k\u013c\u016bda<\/tt><\/p>\n
A ArrayList<String><\/tt> objektu nevar nodot k\u0101 argumentu metodei, kas prasa a ArrayList<Object><\/tt> jo abi veidi ir viena un t\u0101 pa\u0161a visp\u0101r\u012bg\u0101 tipa instancijas, bet priek\u0161 da\u017e\u0101di<\/i> tipa argumentus, un \u0161\u012b iemesla d\u0113\u013c tie nav savietojami viens ar otru.<\/p>\n
Betona parametriz\u0113tie tipi ir visp\u0101r\u012bga tipa konkr\u0113tas instancijas.\u00a0 Tie ir gandr\u012bz l\u012bdz\u012bgi tipiem; ir tikai da\u017ei ierobe\u017eojumi.\u00a0 Tos NEVAR izmantot \u0161\u0101diem m\u0113r\u0137iem:<\/p>\n
\n- mas\u012bvu izveido\u0161anai<\/li>\n
- iz\u0146\u0113mumu apstr\u0101d\u0113<\/li>\n
- klases burtiski<\/li>\n
- in an instanceof<\/tt> izteiksme<\/li>\n<\/ul>\n
Mas\u012bvi, kuros ir elementi, kuru tips ir konkr\u0113ti parametriz\u0113ts tips, ir nelikum\u012bgi.<\/p>\n
Piem\u0113rs (neleg\u0101la mas\u012bva tipa):<\/p>\n
static void test() {<\/tt>
\n \u00a0 P\u0101ris<Vesels skaitlis, Vesels skaitlis>[]<\/span> <\/b> intPairArr = jauns P\u0101ris<Vesels skaitlis, Vesels skaitlis>[10]<\/span> <\/b> ; \/\/ k\u013c\u016bda<\/span> <\/b> <\/tt>
\n \u00a0 addElements(intPairArr);\u00a0<\/tt>
\n \u00a0 P\u0101ris<Integer,Integer> p\u0101ris = intPairArr[1];<\/tt>
\n \u00a0 Vesels skaitlis i = p\u0101ris.getFirst();<\/tt>
\n \u00a0 pair.setSecond(i);<\/tt>
\n }<\/tt>
\n static Void addElements( Objekts[]<\/b> objArr) {<\/tt>
\n \u00a0 objArr[0] = jauns P\u0101ris<Vesels skaitlis, Vesels skaitlis>(0,0);<\/tt>
\n \u00a0 objArr[1] = jauns p\u0101ris<String,String>(\"\",\"\");\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ vajadz\u0113tu neizdoties ar ArrayStoreException<\/tt>
\n }<\/tt><\/p>\nKompilators aizliedz izveidot mas\u012bvus, kuru komponenta tips ir konkr\u0113ts parametriz\u0113ts tips, piem\u0113ram P\u0101ris<Integer,Integer><\/tt> m\u016bsu piem\u0113r\u0101.\u00a0 Iepriek\u0161\u0113j\u0101 ierakst\u0101 m\u0113s apspried\u0101m, k\u0101p\u0113c ir sapr\u0101t\u012bgi, ka kompilators kvalific\u0113 a P\u0101ris<Vesels skaitlis, Vesels skaitlis>[]<\/tt> <\/span> k\u0101 nelikum\u012bgu.\u00a0 Galven\u0101 probl\u0113ma ir t\u0101, ka kompilatoram un izpildlaika sist\u0113mai ir j\u0101nodro\u0161ina, lai mas\u012bvs b\u016btu a viendab\u012bgs<\/i> viena veida elementu sec\u012bba.\u00a0 Viena no veida p\u0101rbaud\u0113m, proti, mas\u012bva veikala p\u0101rbaude, ko veic virtu\u0101l\u0101 ma\u0161\u012bna izpildlaik\u0101, neizdodas atkl\u0101t sve\u0161a elementa aizskaro\u0161u ievieto\u0161anu. Piem\u0113r\u0101 otrais ievietojums addElements<\/tt> metodei vajadz\u0113tu neizdoties, jo vi\u0146i pievienoja virk\u0146u p\u0101ri integr\u0101lo v\u0113rt\u012bbu mas\u012bvam, ta\u010du t\u0101 neizdodas, k\u0101 paredz\u0113ts. Iemesli tika apspriesti iepriek\u0161\u0113j\u0101 ierakst\u0101.<\/p>\nJa m\u0113s nevaram izmantot mas\u012bvus, kas satur elementus, kuru tips ir konkr\u0113ts parametriz\u0113ts tips, ko m\u0113s izmantojam k\u0101 risin\u0101jumu?<\/p>\n
Apsv\u0113rsim 3 iesp\u0113jamos risin\u0101jumus:<\/p>\n
\n- neapstr\u0101d\u0101tu veidu kl\u0101sts<\/li>\n
- neierobe\u017eota aizst\u0101j\u0113jz\u012bmju parametriz\u0113ta tipa mas\u012bvs<\/li>\n
- kolekcija mas\u012bva viet\u0101<\/li>\n<\/ul>\n
Lai gan betona parametru tipu mas\u012bvi ir nelikum\u012bgi, betona parametriz\u0113tu tipu kolekcijas ir at\u013cautas.<\/p>\n
Aizst\u0101j\u0113jz\u012bmes parametriz\u0113tais tips ir visp\u0101r\u0113ja tipa instanc\u0113, kur vismaz viens tipa arguments ir aizst\u0101j\u0113jz\u012bme.\u00a0 Aizst\u0101j\u0113jz\u012bmju parametriz\u0113to tipu piem\u0113ri ir Kolekcija<?><\/tt> , List<? pagarina Number><\/tt> , Comparator<? super String><\/tt> un Pair<String,?><\/tt> . Aizst\u0101j\u0113jz\u012bmes parametriz\u0113tais tips apz\u012bm\u0113 tipu saimi, kas ietver konkr\u0113tas visp\u0101r\u0113ja tipa instancijas.\u00a0 Izmantot\u0101s aizst\u0101j\u0113jz\u012bmes veids nosaka, kuri konkr\u0113tie parametriz\u0113tie veidi pieder saimei.\u00a0 Piem\u0113ram, aizst\u0101j\u0113jz\u012bmes parametriz\u0113tais tips Kolekcija<?><\/tt> apz\u012bm\u0113 visu instanti\u0101ciju saimi Kolekcija<\/tt> interfeiss neatkar\u012bgi no argumenta tipa.\u00a0 Aizst\u0101j\u0113jz\u012bmes parametriz\u0113tais tips List<? pagarina Number><\/tt> apz\u012bm\u0113 visu sarakstu tipu saimi, kur elementa tips ir apak\u0161tips\u00a0 Numurs<\/tt> .\u00a0 Aizst\u0101j\u0113jz\u012bmes parametriz\u0113tais tips Comparator<? super String><\/tt> ir visu instan\u010du saime Sal\u012bdzin\u0101t\u0101js<\/tt> saskarne tipa argumentu tipiem, kas ir supertipi St\u012bga.<\/tt><\/p>\n
Aizst\u0101j\u0113jz\u012bmes parametriz\u0113tais tips nav tips parastaj\u0101 noz\u012bm\u0113 (at\u0161\u0137iras no neparametriz\u0113tas klases\/saskarnes vai neapstr\u0101d\u0101ta tipa).<\/em> <\/strong><\/p>\nRakst\u012b\u0161anai var izmantot aizst\u0101j\u0113jz\u012bmju parametriz\u0113tos tipus (piem\u0113ram, klases un saskarnes bez parametriem):<\/p>\n
\n- k\u0101 argumentu un atgrie\u0161anas veidu metodes<\/li>\n
- k\u0101 lauka vai viet\u0113j\u0101 atsauces main\u012bg\u0101 veids<\/li>\n
- k\u0101 citu parametriz\u0113tu tipu mas\u012bva tipa argumenta komponenta tips<\/li>\n
- k\u0101 m\u0113r\u0137a veids metienos<\/li>\n<\/ul>\n
Ne tikai veidi var b\u016bt visp\u0101r\u012bgi, bet ar\u012b metodes var b\u016bt visp\u0101r\u012bgas. Statisk\u0101m un nestatisk\u0101m metod\u0113m, k\u0101 ar\u012b konstruktoriem var b\u016bt tipa parametri. Form\u0101lo tipu parametru deklar\u0113\u0161anas sintakse ir l\u012bdz\u012bga visp\u0101r\u012bgo tipu sintaksei. Tipa parametra sada\u013ca ir norobe\u017eota ar le\u0146\u0137a iekav\u0101m un par\u0101d\u0101s pirms metodes atgrie\u0161anas veida. T\u0101 sintakse un noz\u012bme ir identiska visp\u0101r\u012bg\u0101 tipa tipa parametru sarakstam.<\/p>\n
\u0160eit ir sugas piem\u0113rs maks<\/tt> metode, kas apr\u0113\u0137ina liel\u0101ko v\u0113rt\u012bbu nezin\u0101ma veida elementu kolekcij\u0101 A<\/tt> .<\/p>\n
Piem\u0113rs (visp\u0101r\u0113jai metodei):<\/p>\n
klases kolekcijas {<\/tt>
\n \u00a0 publiska statiska <A pagarina Sal\u012bdzin\u0101ms<A>> A<\/span> <\/b> max (Kolekcija< A<\/span> <\/b> > xs) {<\/tt>
\n \u00a0\u00a0\u00a0 Iterators< A<\/span> <\/b> > xi = xs.iterator();<\/tt>
\n \u00a0\u00a0\u00a0 A<\/span> <\/b> w = xi.next();<\/tt>
\n \u00a0\u00a0\u00a0 while (xi.hasNext()) {<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0 A<\/span> <\/b> x = xi.next();<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0 ja (w.sal\u012bdzin\u0101tTo(x) < 0) w = x;<\/tt>
\n \u00a0\u00a0\u00a0 }<\/tt>
\n \u00a0\u00a0\u00a0 atgriezties w;<\/tt>
\n \u00a0 }<\/tt>
\n }\u00a0<\/tt><\/p><\/blockquote>\nThe maks<\/tt> metodei ir viens tipa parametrs, nosaukts A<\/tt> .\u00a0 Tas ir vietas tur\u0113t\u0101js kolekcijas elementa tipam, kur\u0101 darbojas metode. Tipa parametram ir ierobe\u017eojums; tam ir j\u0101b\u016bt veidam, kas ir apak\u0161tips Sal\u012bdzin\u0101ms<A><\/tt><\/p>\n
Piem\u0113rs (\u0161oreiz t\u0101 pa\u0161a visp\u0101r\u012bg\u0101 tipa ar<\/i> robe\u017eas):<\/p>\n publiska saskarne Sal\u012bdzin\u0101ms<T> {<\/tt>
\n \u00a0 publisks int sal\u012bdzin\u0101tTo(T arg);<\/tt>
\n }<\/tt>
\n publisk\u0101 klase TreeMap<Key pagarina Sal\u012bdzin\u0101ms<Key><\/span> <\/b> ,Data>{<\/tt>
\n \u00a0 priv\u0101t\u0101 statisk\u0101 klase Entry<K,V> {<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 K tausti\u0146\u0161;<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 V v\u0113rt\u012bba;<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 Entry<K,V> pa kreisi = null;<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 Entry<K,V> pa labi = null;<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 Entry<K,V> vec\u0101ks;<\/tt>
\n \u00a0 }<\/tt>
\n \u00a0 priv\u0101ts p\u0101rejo\u0161s Entry<Key,Data> sakne = null;<\/tt>
\n \u00a0 ...<\/tt>
\n \u00a0 priv\u0101t\u0101 ievade<Key,Data> getEntry (atsl\u0113gas atsl\u0113ga) {<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 Entry<Key,Data> p = sakne;<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 Tausti\u0146\u0161 k = atsl\u0113ga;<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 while (p != null) {<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 int cmp = k. sal\u012bdzin\u0101tTo(p.key)<\/span> <\/b> ;\u00a0<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ja (cmp == 0)<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 atgriezties p;<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 cit\u0101di, ja (cmp < 0)<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 p = p.pa kreisi;<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 cits\u00a0<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 p = p.pa labi;\u00a0<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 }<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 return null;<\/tt>
\n \u00a0 }<\/tt>
\n \u00a0 publiskais B\u016bla satursKey(Key key) {<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 atgriezties getEntry(atsl\u0113ga) != null;<\/tt>
\n \u00a0 }<\/tt>
\n \u00a0 ...<\/tt>
\n }<\/tt><\/p><\/blockquote>\nIepriek\u0161 min\u0113taj\u0101 piem\u0113r\u0101 tipa parametrs Atsl\u0113ga<\/tt> ir saist\u012bts Sal\u012bdzin\u0101ms<Key><\/tt> .\u00a0 Iesie\u0161anas specifik\u0101cijai ir divas sekas:<\/p>\n\n- Tas nodro\u0161ina piek\u013cuvi metod\u0113m, kuras nosaka saite<\/i> .\u00a0 Piem\u0113r\u0101 iesiets Sal\u012bdzin\u0101ms<Key> <\/tt> nodro\u0161ina piek\u013cuvi sal\u012bdzin\u0101t Ar<\/tt> metode, kuru m\u0113s v\u0113lamies izmantot, \u012bstenojot m\u016bsu TreeMap<\/tt> klas\u0113.<\/li>\n<\/ul>\n
\n- Visp\u0101r\u0113j\u0101 tipa instanti\u0101cijai var izmantot tikai tipus “ierobe\u017e\u0101s”.<\/i> \u00a0 Piem\u0113r\u0101 parametriz\u0113ts tips, piem\u0113ram, TreeMap<Number,String><\/tt> tiktu noraid\u012bts, jo tips Numurs<\/tt> nav apak\u0161tips Sal\u012bdzin\u0101ms<Number><\/tt> .\u00a0 T\u0101ds parametriz\u0113ts tips k\u0101 TreeMap<String,String><\/tt> tiktu pie\u0146emts, jo tips String ir robe\u017e\u0101s, t.i., ir apak\u0161tips Sal\u012bdzin\u0101ms<String><\/tt> .<\/li>\n<\/ul>\n
Visas klases, saskarnes un enum tipus var izmantot k\u0101 tipa parametru saist\u012btus, tostarp ligzdotos un iek\u0161\u0113jos tipus.\u00a0 Ne primit\u012bvie tipi, ne mas\u012bvu veidi netiek izmantoti k\u0101 tipa parametru saist\u012bba.<\/p>\n
Piem\u0113ri (tipa parametru robe\u017e\u0101m):<\/p>\n
klase X0 <T pagarina starpt<\/span> <\/b> > { ... }\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ k\u013c\u016bda<\/span> <\/b> <\/tt>
\n klase X1 <T pagarina Objekts[]<\/span> <\/b> > { ... } \/\/ k\u013c\u016bda<\/span> <\/b> <\/tt>
\n klase X2 <T pagarina Numurs<\/span> <\/b> > { ... }<\/tt>
\n klase X3 <T pagarina St\u012bga<\/span> <\/b> > { ... }<\/tt>
\n klase X4 <T pagarina Palaist<\/span> <\/b> > { ... }<\/tt>
\n klase X5 <T pagarina Pavediens.Valsts<\/span> <\/b> > { ... }<\/tt>
\n klase X6 <T pagarina Saraksts<\/span> <\/b> > { ... }<\/tt>
\n klase X7 <T pagarina Saraksts<String><\/span> <\/b> > { ... }<\/tt>
\n klase X8 <T pagarina List<? pagarina Number><\/span> <\/b> > { ... }<\/tt>
\n klase X9 <T pagarina Sal\u012bdzin\u0101ms<? super numurs><\/span> <\/b> > { ... }<\/tt>
\n klase X10<T pagarina Karte.Entry<?,?><\/span> <\/b> > { ... }<\/tt><\/p><\/blockquote>\nKoda paraugs par\u0101da, ka primit\u012bvie veidi, piem\u0113ram, starpt<\/tt> un mas\u012bvu veidi, piem\u0113ram, Objekts[] <\/tt> nav at\u013cauti k\u0101 tipa parametri.<\/p>\n
Klases veidi, piem\u0113ram Numurs<\/tt> vai St\u012bga<\/tt> , un saskarnes veidi, piem\u0113ram, Palaist<\/tt> , ir at\u013cauti k\u0101 tipa parametri.<\/p>\n
Enum veidi, piem\u0113ram Pavediens.Valsts<\/tt> ir at\u013cauti ar\u012b k\u0101 tipa parametri. Pavediens.Valsts<\/tt> ir ligzdot\u0101 tipa piem\u0113rs, kas tiek izmantots k\u0101 tipa parametru ierobe\u017eojums.\u00a0 Ir at\u013cauti ar\u012b nestatiski iek\u0161\u0113jie veidi.<\/p>\n
Neapstr\u0101d\u0101ti tipi ir at\u013cauti k\u0101 tipa parametru ierobe\u017eojumi; Saraksts<\/span> <\/tt> ir piem\u0113rs.<\/p>\nParametru tipi ir at\u013cauti k\u0101 tipa parametri, tostarp konkr\u0113ti parametriz\u0113ti tipi, piem\u0113ram, Saraksts<String><\/tt> , ierobe\u017eoti aizst\u0101j\u0113jz\u012bmes parametriz\u0113tie tipi, piem\u0113ram, List<? pagarina Number><\/tt> un Sal\u012bdzin\u0101ms<? super Long><\/tt> , un neierobe\u017eoti aizst\u0101j\u0113jz\u012bmju parametriz\u0113tie veidi, piem\u0113ram, Karte.Entry<?,?><\/tt> .\u00a0 Iesaist\u012bjums, kas ir aizst\u0101j\u0113jz\u012bmes parametriz\u0113ts tips, k\u0101 tipa arguments \u013cauj izmantot visus veidus, kas pieder tipu saimei, ko apz\u012bm\u0113 aizst\u0101j\u0113jz\u012bme.\u00a0 Aizst\u0101j\u0113jz\u012bmes parametriz\u0113t\u0101 tipa saist\u012bba nodro\u0161ina tikai ierobe\u017eotu piek\u013cuvi laukiem un metod\u0113m; ierobe\u017eojumi ir atkar\u012bgi no aizst\u0101j\u0113jz\u012bmes veida.<\/p>\n
Piem\u0113rs (aizst\u0101j\u0113jz\u012bmes parametriz\u0113tam tipam k\u0101 tipa parametra ierobe\u017eojumam):<\/p>\n
klase X< T pagarina List<? pagarina Number><\/span> <\/b> > {<\/tt>
\n \u00a0 public void someMethod(T t) {<\/tt>
\n \u00a0\u00a0\u00a0 t.add(new Long(0L));\u00a0\u00a0\u00a0 \/\/ k\u013c\u016bda<\/span> <\/b> <\/tt>
\n \u00a0\u00a0\u00a0 Skaitlis n = t.remove(0);<\/tt>
\n \u00a0 }<\/tt>
\n }<\/tt>
\n klases ieskaite {<\/tt>
\n \u00a0 public static void main(String[] args) {<\/tt>
\n \u00a0\u00a0\u00a0\u00a0 <\/span> <\/b> X<ArrayList<<\/span> Gar\u0161<\/span> <\/b> >> x1 = jauns X<ArrayList<Long>>();\u00a0<\/span> <\/tt>
\n \u00a0\u00a0\u00a0\u00a0 X<ArrayList<<\/span> St\u012bga<\/span> <\/b> >> x2 = jauns X<ArrayList<String>>(); <\/span> \/\/ k\u013c\u016bda<\/span> <\/b> <\/tt>
\n \u00a0 }<\/tt>
\n }<\/tt><\/p><\/blockquote>\nTipa atsauces main\u012bgie T <\/tt> (tipa parametrs) tiek apstr\u0101d\u0101ti k\u0101 aizst\u0101j\u0113jz\u012bmes tipa atsauces main\u012bgie (tipa parametrs ir saist\u012bts).\u00a0 M\u016bsu piem\u0113r\u0101 sekas ir t\u0101das, ka kompilators noraida t\u0101du meto\u017eu izsauk\u0161anu, kas izmanto “nezin\u0101ma” tipa argumentu, ko apz\u012bm\u0113 tipa parametrs, piem\u0113ram, List.add<\/tt> , jo saist\u012bba ir aizst\u0101j\u0113jz\u012bmes parametriz\u0113ts tips ar aug\u0161\u0113jo robe\u017eu.
\nTaj\u0101 pa\u0161\u0101 laik\u0101 saisto\u0161s List<? pagarina Number><\/tt> nosaka veidus, kurus var izmantot k\u0101 tipa argumentus. Kompilators pie\u0146em visus tipa argumentus, kas pieder tipu saimei List<? pagarina Number><\/tt> , tas ir, visi apak\u0161tipi Saraksts<\/tt> ar tipa argumentu, kas ir apak\u0161tips Numurs<\/tt> .<\/p>\n
Tipa parametru var izmantot k\u0101 cita tipa parametra saiti.<\/p>\n
Piem\u0113rs (tipa parametram, ko izmanto k\u0101 tipa parametra ierobe\u017eojumu):<\/p>\n
klase Tr\u012bsk\u0101r\u0161s <T><\/b> {<\/tt>
\n \u00a0 priv\u0101tais T fst, snd, trd;<\/tt>
\n \u00a0 publiskais < U<\/b> pagarina T<\/span> <\/b> , V pagarina T<\/span> <\/b> , W pagarina T<\/span> <\/b> > Triple(U arg1, V arg2, W arg3) {<\/tt>
\n \u00a0\u00a0\u00a0 fst = arg1;<\/tt>
\n \u00a0\u00a0\u00a0 snd = arg2;<\/tt>
\n \u00a0\u00a0\u00a0 trd = arg3;<\/tt>
\n \u00a0 }<\/tt>
\n }<\/tt><\/p><\/blockquote>\n\u0160aj\u0101 piem\u0113r\u0101 tipa parametrs T<\/tt> no parametriz\u0113t\u0101s klases tiek izmantota k\u0101 tipa parametru saist\u012bba U<\/tt> ,\u00a0 V<\/tt> un W<\/tt> \u0161\u012bs klases parametriz\u0113t\u0101s instances metodi.<\/p>\n
Citas iesp\u0113jas izmantot tipa parametrus k\u0101 citu tipa parametru robe\u017eas ietver situ\u0101cijas, kad ligzdots tips ir defin\u0113ts visp\u0101r\u012bg\u0101 tipa iek\u0161pus\u0113 vai viet\u0113j\u0101 klase ir defin\u0113ta visp\u0101r\u012bg\u0101 metod\u0113.\u00a0 Ir pat at\u013cauts izmantot tipa parametru k\u0101 cita tipa parametra saist\u012bbu taj\u0101 pa\u0161\u0101 tipa parametru sada\u013c\u0101.<\/p>\n
Iesaist\u012bjums, kas ir klase, nodro\u0161ina piek\u013cuvi visiem t\u0101s publiskajiem dal\u012bbniekiem, tas ir, publiskajiem laukiem, metod\u0113m un ligzdotajiem veidiem. Tikai konstruktori netiek padar\u012bti pieejami, jo nav garantijas, ka saites apak\u0161klasei ir t\u0101di pa\u0161i konstruktori k\u0101 saitei.<\/p>\n
Piem\u0113rs (klasei, ko izmanto k\u0101 tipa parametra saiti):<\/p>\n
publiska klase Superklase<\/span> {<\/tt> \u00a0\u00a0\u00a0 \/\/ statiski dal\u012bbnieki<\/tt>
\n \u00a0\u00a0\u00a0 publiskais saraksts EnumType {THIS, THAT}<\/tt>
\n \u00a0\u00a0\u00a0 public static Object staticField;<\/tt>
\n \u00a0\u00a0\u00a0 public static void staticMethod() { ... }<\/tt><\/p>\n \u00a0\u00a0\u00a0 \/\/ nestatiski dal\u012bbnieki<\/tt>
\n \u00a0\u00a0\u00a0 publiska klase InnerClass { ... }<\/tt>
\n \u00a0\u00a0\u00a0 publiskais objekts nonStaticField;<\/tt>
\n \u00a0\u00a0\u00a0 public void nonStaticMethod() { ... }<\/tt><\/p>\n
\u00a0\u00a0\u00a0 \/\/ konstruktori<\/tt>
\n \u00a0\u00a0\u00a0 publiska SuperClass() { ... }<\/tt><\/p>\n
\u00a0\u00a0\u00a0 \/\/ priv\u0101tie dal\u012bbnieki<\/tt>
\n \u00a0\u00a0\u00a0 private Object privateField;\u00a0<\/tt><\/p>\n
\u00a0\u00a0\u00a0 ...<\/tt>
\n }<\/tt><\/p>\n
publisk\u0101 fin\u0101la klase SomeClass<T pagarina Superklase<\/span> <\/b> > {<\/tt>
\n \u00a0\u00a0\u00a0 priv\u0101tais T objekts;<\/tt>
\n \u00a0\u00a0\u00a0 public SomeClass(T t) { objekts = t; }\u00a0<\/tt><\/p>\n \u00a0\u00a0\u00a0 public String toString() {<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 atgriezties<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \"static ligzdota tips\u00a0\u00a0\u00a0 : \"+T.EnumType.class+\"\\n\"\u00a0<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 +\"statiskais lauks\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 : \"+T.staticField+\"\\n\"<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 +\"statisk\u0101 metode\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 : \"+T.staticMethod()+\"\\n\"<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 +\"nestatisks ligzdots veids: \"+T.InnerClass.class+\"\\n\"<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 +\"nestatisks lauks\u00a0\u00a0\u00a0\u00a0\u00a0 : \"+object.nonStaticField+\"\\n\"<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 +\"nestatisk\u0101 metode\u00a0\u00a0\u00a0\u00a0 : \"+object.nonStaticMethod()+\"\\n\"<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 +\"konstruktors\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 : \"+(jauns T())+\"\\n\"\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ k\u013c\u016bda<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 +\"priv\u0101ts dal\u012bbnieks\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 : \"+object.privateField+\"\\n\"\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ k\u013c\u016bda\u00a0<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ;<\/tt>
\n \u00a0\u00a0\u00a0 }<\/tt>
\n }<\/tt><\/p><\/blockquote>\n
Saist\u012bts Superklase<\/tt> nodro\u0161ina piek\u013cuvi t\u0101 ligzdotajiem veidiem, statiskajiem laukiem un metod\u0113m, k\u0101 ar\u012b nestatiskajiem laukiem un metod\u0113m.\u00a0 Tikai konstruktors nav pieejams.\u00a0 Tas ir t\u0101p\u0113c, ka konstruktori netiek mantoti. Katra apak\u0161klase defin\u0113 savus konstruktorus, un tai nav j\u0101atbalsta savas virsklases konstruktori.\u00a0 T\u0101d\u0113j\u0101di nav garantijas, ka apak\u0161klase Superklase<\/tt> b\u016bs t\u0101ds pats konstruktors k\u0101 t\u0101s superklasei.<\/p>\n
Konteksts, kur\u0101 Enum<E papla\u0161ina Enum<E>><\/tt> Par\u0101d\u0101s deklar\u0101cija Enum<\/tt> klase iepakojum\u0101 java.lang<\/tt> :<\/p>\n publiska abstrakt\u0101 klase Enum<E papla\u0161ina Enum<E>><\/b> {<\/tt>
\n \u00a0 ...<\/tt>
\n }<\/tt><\/p><\/blockquote>\n
Veids Enum<\/tt> ir visu uzskait\u012b\u0161anas veidu kop\u0113j\u0101 b\u0101zes klase.\u00a0 Java valod\u0101 uzskaites veids, piem\u0113ram, Kr\u0101sa<\/tt> tiek tulkots klas\u0113 Kr\u0101sa<\/tt> kas pagarina Enum<Color><\/tt> . Superklases m\u0113r\u0137is Enum<\/tt> ir nodro\u0161in\u0101t funkcionalit\u0101ti, kas ir kop\u012bga visiem uzskait\u012b\u0161anas veidiem.<\/p>\n
\u0160eit ir klases skice Enum<\/tt> :<\/p>\n publiska abstrakt\u0101 klase Enum< E<\/span> pagarina Enum<E>><\/b> ievie\u0161 Comparable< E<\/span> <\/b> >, serializ\u0113jams {<\/tt>
\n \u00a0 priv\u0101ts beigu virknes nosaukums;<\/tt>
\n \u00a0 publiskais gala virknes nosaukums() { ... }<\/tt> \u00a0 priv\u0101ts gala ind ordin\u0101ls;<\/tt>
\n \u00a0 public final int ordinal() { ... }<\/tt><\/p>\n \u00a0 Protected Enum (virknes nosaukums, int k\u0101rtas) { ... }<\/tt><\/p>\n
\u00a0 public String\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 toString() { ... }<\/tt>
\n \u00a0 publiska gal\u012bg\u0101 B\u016bla v\u0113rt\u012bba ir vien\u0101da (Object other) { ... }<\/tt>
\n \u00a0 public final int hashCode() { ... }<\/tt>
\n \u00a0 aizsarg\u0101ts gala Objekta klons() izmet CloneNotSupportedException { ... }<\/tt>
\n \u00a0 publisks gala int sal\u012bdzin\u0101tTo( E<\/span> <\/b> o) {...}<\/tt><\/p>\n \u00a0 publiskais fin\u0101ls Class< E<\/span> <\/b> > getDeclaringClass() { ... }<\/tt>
\n \u00a0 publiskais statiskais <T papla\u0161ina Enum<T>> T valueOf(Class<T> enumType, virknes nosaukums) { ... }<\/tt>
\n }<\/tt><\/p><\/blockquote>\nP\u0101rsteidzo\u0161\u0101 iez\u012bme deklar\u0101cij\u0101 “ Enum<E papla\u0161ina Enum<E>><\/tt> ” ir fakts, ka jaunizveidot\u0101 klase Enum<\/tt> un t\u0101 jaundefin\u0113tais tipa parametrs E <\/tt> par\u0101d\u0101s t\u0101 pa\u0161a tipa parametra robe\u017e\u0101s.\u00a0 Tas noz\u012bm\u0113, ka Enum<\/tt> tips ir j\u0101veido vienam no t\u0101 apak\u0161tipiem.\u00a0 Lai saprastu, k\u0101p\u0113c tas ir j\u0113ga, \u0146emiet v\u0113r\u0101, ka katrs enum veids tiek tulkots apak\u0161tip\u0101 Enum<\/tt> .<\/p>\n
\u0160eit ir izdom\u0101ts enum veids Kr\u0101sa<\/tt> :<\/p>\n enum Kr\u0101sa<\/b> {SARKANS, ZILS, ZA\u013bS}<\/tt><\/p><\/blockquote>\n
Kompilators to p\u0101rtulko \u0161\u0101d\u0101 klas\u0113:<\/p>\n
publisk\u0101 nosl\u0113guma klase Kr\u0101sa<\/b> pagarina Enum<Color><\/b> {<\/tt>
\n \u00a0 public static final Color[] value() { return (Color[])$VALUES.clone(); }<\/tt>
\n \u00a0 public static Color valueOf(virknes nosaukums) { ... }<\/tt> \u00a0 priv\u0101t\u0101 Kr\u0101sa(String s, int i) { super(s, i); }<\/tt><\/p>\n
\u00a0 publiska statiska gala Kr\u0101sa SARKANA;<\/tt>
\n \u00a0 publiska statisk\u0101 fin\u0101la Kr\u0101sa ZILA;<\/tt>
\n \u00a0 publiska statisk\u0101 gala Kr\u0101sa ZA\u013bA;<\/tt><\/p>\n
\u00a0 priv\u0101ts statisks gala Kr\u0101sa $VALUES[];<\/tt><\/p>\n
\u00a0 static {<\/tt>
\n \u00a0\u00a0\u00a0 SARKANS = jauna kr\u0101sa (\"SARKANS\", 0);<\/tt>
\n \u00a0\u00a0\u00a0 ZILS = new Color(\"ZILS\", 1);<\/tt>
\n \u00a0\u00a0\u00a0 ZA\u013bS = jauna kr\u0101sa (\"ZA\u013bA\", 2);<\/tt>
\n \u00a0\u00a0\u00a0 $V\u0112RT\u012aBAS = (jauna kr\u0101sa[] { SARKANS, ZILS, ZA\u013bS });<\/tt>
\n \u00a0 }<\/tt>
\n }<\/tt><\/p><\/blockquote>\n
Mantojumam ir t\u0101da ietekme, ka Kr\u0101sa<\/tt> tips manto visas taj\u0101 ieviest\u0101s metodes Enum<Color><\/tt> .\u00a0 Starp tiem ir sal\u012bdzin\u0101t Ar<\/tt> metodi.\u00a0 The Kr\u0101sa. sal\u012bdzin\u0101t Ar<\/tt> metodei, iesp\u0113jams, vajadz\u0113tu \u0146emt a Kr\u0101sa<\/tt> k\u0101 arguments.\u00a0 Lai tas notiktu klase Enum<\/tt> ir visp\u0101r\u012bgs un Enum.compareTo<\/tt> metode aiz\u0146em Enum<\/tt> tipa parametrs E <\/tt> k\u0101 arguments.\u00a0 Rezult\u0101t\u0101 ierakstiet Kr\u0101sa<\/tt> atvasin\u0101ts no Enum<Color><\/tt> manto a sal\u012bdzin\u0101t Ar<\/tt> metode, kas prasa a Kr\u0101sa<\/tt> k\u0101 un arguments, tie\u0161i t\u0101, k\u0101 vajadz\u0113tu.
\nJa m\u0113s sadal\u0101m deklar\u0101ciju “ Enum<E papla\u0161ina Enum<E>><\/tt> “M\u0113s redzam, ka \u0161im modelim ir vair\u0101ki aspekti.<\/p>\n
Pirmk\u0101rt, ir fakts, ka tipa parametra saist\u012bba ir pats tips: “ Enum<\/b> <E pagarina Enum<\/b> <E>><\/tt> “. Tas nodro\u0161ina, ka tikai tipa apak\u0161tipi Enum<\/tt> ir at\u013cauti k\u0101 tipa argumenti. (Teor\u0113tiski ierakstiet Enum<\/tt> var\u0113tu b\u016bt iemiesojum\u0101 pats par sevi, piem\u0113ram, in Enum<Enum><\/tt> , ta\u010du tas noteikti nav dom\u0101ts, un ir gr\u016bti iedom\u0101ties situ\u0101ciju, kur\u0101 \u0161\u0101da instanc\u0113 b\u016btu noder\u012bga.)<\/p>\n
Otrk\u0101rt, ir fakts, ka ar parametru saist\u012btais tips ir parametriz\u0113tais tips Enum <E><\/b> <\/tt> , kas izmanto tipa parametru E<\/tt> k\u0101 saist\u012bjuma tipa arguments. \u0160\u012b deklar\u0101cija nodro\u0161ina mantojuma attiec\u012bbu starp apak\u0161tipu un instanti\u0101ciju Enum<\/tt> ir formas X papla\u0161ina Enum<X><\/tt> “. Apak\u0161tips, piem\u0113ram, “ X papla\u0161ina Enum<Y><\/tt> ” nevar deklar\u0113t tipa argumenta d\u0113\u013c Y<\/tt> neb\u016btu robe\u017e\u0101s; tikai apak\u0161tipi Enum<X><\/tt> ir robe\u017e\u0101s.<\/p>\n
Tre\u0161k\u0101rt, ir fakts, ka Enum<\/tt> pirmk\u0101rt, ir visp\u0101r\u012bgs.\u00a0 Tas noz\u012bm\u0113, ka da\u017eas no klases metod\u0113m Enum<\/tt> \u0146emt argumentu vai atgriezt nezin\u0101ma tipa v\u0113rt\u012bbu (vai cit\u0101di b\u016bt atkar\u012bga no nezin\u0101ma veida). K\u0101 m\u0113s jau zin\u0101m, \u0161is nezin\u0101mais tips v\u0113l\u0101k b\u016bs apak\u0161tips X<\/tt> no Enum<X><\/tt> .\u00a0 T\u0101d\u0113j\u0101di parametriz\u0113taj\u0101 tip\u0101 Enum<X><\/tt> , \u0161\u012bs metodes ietver apak\u0161tipu X<\/tt> , un tie tiek mantoti apak\u0161tip\u0101 X<\/tt> .\u00a0 The sal\u012bdzin\u0101t Ar<\/tt> metode ir \u0161\u0101das metodes piem\u0113rs; tas tiek mantots no virsklases katr\u0101 apak\u0161klas\u0113, un katr\u0101 gad\u012bjum\u0101 tam ir apak\u0161klasei specifisks paraksts.<\/p>\n
Rezum\u0113jot, deklar\u0101cija “ Enum<E papla\u0161ina Enum<E>><\/tt> ” var at\u0161ifr\u0113t \u0161\u0101di: Enum<\/tt> ir visp\u0101r\u012bgs tips, ko var iemiesot tikai t\u0101 apak\u0161tipiem, un \u0161ie apak\u0161tipi p\u0101rmantos da\u017eas noder\u012bgas metodes, no kur\u0101m da\u017eas izmanto apak\u0161tipam specifiskus argumentus (vai cit\u0101di ir atkar\u012bgi no apak\u0161tipa).<\/p>\n
Kla\u0161u apak\u0161\u0113j\u0101s robe\u017eas tipa parametri<\/b><\/p>\n
Tipa parametriem var b\u016bt vair\u0101kas robe\u017eas, piem\u0113ram, in klases Box<T pagarina Number> {...}<\/tt> . Bet tipa parametram nevar b\u016bt zem\u0101kas robe\u017eas, tas ir, t\u0101da konstrukcija k\u0101 klases Box<T lieliski<\/b> Numurs> {...}<\/tt> nav at\u013cauts.\u00a0 K\u0101p\u0113c ne?\u00a0 Atbilde ir: tas ir bezj\u0113dz\u012bgi, jo tas jums neko nepirktu, ja tas b\u016btu at\u013cauts.\u00a0 Redz\u0113sim, k\u0101p\u0113c kla\u0161u apak\u0161\u0113j\u0101s robe\u017eas tipa parametri ir mulsino\u0161i, izp\u0113tot, ko noz\u012bm\u0113 tipa parametra aug\u0161\u0113j\u0101 robe\u017ea.<\/p>\n
Tipa parametra aug\u0161\u0113jai robe\u017eai ir tr\u012bs efekti:<\/p>\n
\n\n- Ierobe\u017eota instanc\u0113.<\/i> <\/b> Aug\u0161\u0113j\u0101 robe\u017ea ierobe\u017eo veidu kopu, ko var izmantot visp\u0101r\u012bg\u0101 tipa instanc\u0113m.\u00a0 Ja m\u0113s pasludin\u0101m a klases Box<T pagarina Number> {...} <\/tt> tad kompilators nodro\u0161in\u0101tu, ka tikai apak\u0161tipi Numurs<\/tt> var izmantot k\u0101 tipa argumentu.\u00a0 Tas ir, a Kaste<Number><\/tt> vai a Kaste<Long><\/tt> ir at\u013cauts, bet a Box<Object><\/tt> vai Box<String><\/tt> tiktu noraid\u012bts<\/li>\n<\/ol>\n<\/ol>\n
Piem\u0113rs (ierobe\u017eotai instanti\u0101cijai tipa parametra aug\u0161\u0113j\u0101s robe\u017eas d\u0113\u013c):
\n klases Box<T pagarina Number> {\u00a0<\/tt>
\n \u00a0\u00a0 priv\u0101t\u0101 T v\u0113rt\u012bba;\u00a0<\/tt>
\n \u00a0\u00a0 publisk\u0101 kaste(T t) { v\u0113rt\u012bba = t; }\u00a0<\/tt>
\n \u00a0\u00a0 ...<\/tt>
\n }\u00a0<\/tt> klases ieskaite {\u00a0<\/tt>
\n \u00a0\u00a0 public static void main(String[] args) {\u00a0<\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Box<Long> boxOfLong = jauns Box<Long>(0L);\u00a0\u00a0 \/\/ labi<\/b> <\/tt>
\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Box<String> boxOfString = jauns Box<String>(\"\"); \/\/ k\u013c\u016bda: virkne nav robe\u017e\u0101s<\/span> <\/b> <\/tt>
\n \u00a0\u00a0 }<\/tt>
\n }<\/tt><\/p>\n\n- Piek\u013cuve nestatiskajiem dal\u012bbniekiem. <\/i> <\/b> Aug\u0161\u0113j\u0101 robe\u017ea nodro\u0161ina piek\u013cuvi vis\u0101m publiskaj\u0101m nestatiskaj\u0101m metod\u0113m un aug\u0161\u0113j\u0101s robe\u017eas laukiem.\u00a0 \u012astenojot m\u016bsu klases Box<T pagarina Number> {...}<\/tt> m\u0113s varam izsaukt visas klas\u0113 defin\u0113t\u0101s publisk\u0101s nestatisk\u0101s metodes Numurs<\/tt> , piem\u0113ram, intValue()<\/tt> piem\u0113ram.\u00a0 Bez aug\u0161\u0113j\u0101s robe\u017eas kompilators noraid\u012btu jebkuru \u0161\u0101du izsauk\u0161anu. Piem\u0113rs (piek\u013cuve nestatiskiem dal\u012bbniekiem tipa parametra aug\u0161\u0113j\u0101s robe\u017eas d\u0113\u013c):<\/li>\n<\/ol>\n
klases Box<T pagarina Number> {\u00a0<\/tt>
\n \u00a0\u00a0 priv\u0101t\u0101 T v\u0113rt\u012bba;\u00a0<\/tt>
\n \u00a0\u00a0 publisk\u0101 kaste(T t) { v\u0113rt\u012bba = t; }\u00a0<\/tt>
\n \u00a0\u00a0 public int increment() { return value.intValue()+1; } \/\/ <= b\u016btu k\u013c\u016bda, ja numurs neb\u016btu saist\u012bts<\/b> <\/tt>
\n \u00a0\u00a0 ...<\/tt>