"Effective Java" 9, using Enummap instead of ordinal index

 PackageCn.xf.cp.ch02.item33;ImportJava.util.EnumMap;ImportJava.util.HashSet;ImportJava.util.Map;ImportJava.util.Set;Importorg.junit.Test;/*** Function: Ordinal index * Time: 4:24:48 * File: Herbold.java *@authorAdministrator **/ Public classherbold{ Public enumType {Annual, perennial, biennial}PrivateString name; Privatetype type; /*** Package Area Permissions *@paramname *@paramtype*/Herbold (String name, type type) { This. Name =name;  This. Type =type; } @Override PublicString toString () {returnname; }     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }     PublicType GetType () {returntype; }     Public voidsetType (Type type) { This. Type =type; }    }

Use the results of the ordinal and Enummap respectively:

 PackageCn.xf.cp.ch02.item33;ImportJava.util.EnumMap;ImportJava.util.HashSet;ImportJava.util.Map;ImportJava.util.Set;Importorg.junit.Test;ImportCn.xf.cp.ch02.item33.HerbOld.Type; Public classherbtest{@Test Public voidtes1t () {herbold garden[]=        { NewHerbold ("Basil", type.annual),NewHerbold ("Carroway", type.biennial),NewHerbold ("Dill", type.annual),NewHerbold ("Lavendar", type.perennial),NewHerbold ("Parsley", type.biennial),NewHerbold ("Rosemary", Type.perennial)}; //using the map, the key storage type, the value holds the collection, the Enummap is specifically used for enumeration keys in the mapMapNewEnummapclass); //Create a collection of all types         for(Herbold.type t:herbold.type.values ()) Herbsbytype.put (T,NewHashset());  for(Herbold H:garden) Herbsbytype.get (H.gettype ()). Add (h);    System.out.println (Herbsbytype); }
　　
@Test Public voidtest1 () {herbold garden[]=        { NewHerbold ("Basil", type.annual),NewHerbold ("Carroway", type.biennial),NewHerbold ("Dill", type.annual),NewHerbold ("Lavendar", type.perennial),NewHerbold ("Parsley", type.biennial),NewHerbold ("Rosemary", Type.perennial)}; //when using the collection of this class, we have three kinds of this type, so we want to separate the set, three sets represent annual, perennial,//biennial three types//Create a relative number of arrayssetNewset[herbold.type.values (). length]; //the corresponding set type creates the corresponding set set         for(inti = 0; i < herbsbytype.length; ++i) {Herbsbytype[i]=NewHashset(); }        //determines the position of the corresponding type collection based on the location of the enumeration type and adds the data to it         for(Herbold ho:garden) {//ordinal, this returns the position of the enumeration type at the time of declarationHerbsbytype[ho.gettype (). Ordinal ()].add (HO); }        //Traverse         for(inti = 0; i < herbsbytype.length; ++i) {//This is a running operation here.            /*** But here's a note: When you access an index that is indexed by an enumerated ordinal, you know exactly what type of int represents the enum, and you have to think about it, * How to correctly use an int corresponding to the set type is the corresponding * While int does not provide security for enumerated types. If you use the wrong value, the program will silently complete the unexpected work .*/System.out.printf ("%s:%s%n", HerbOld.Type.values () [i], herbsbytype[i]); }    }}

Ordinal:

Test1 ()

Using enummap,tes1t

"Effective Java" 9, using Enummap instead of ordinal index