27. Using Generic Collections

/*** Pet, Dog and Penguin parent class*/ Public Abstract classPet {protectedString name = "Anonymous";//Nickname    protected intHealth = 100;//Health Value    protected intLove = 0;//Degree of intimacy         Public Abstract voidEat ();//abstract method Eat (), responsible for the pet meal function.         /*** Non-parametric construction method. */     PublicPet () {}/*** A method for constructing a parameter. * @paramName Nickname*/     PublicPet (String name) { This. Name =name; }     PublicString GetName () {returnname; }     Public intGethealth () {returnHealth ; }     Public intGetlove () {returnLove ; }    /*** Output pet information. */     Public voidprint () {System.out.println ("The Confession of the pet: \ n My name is" + This. Name + ", health value is" + This. Health + ", and the intimacy of the host is" + This. Love + ". "); }}

/*** Doggy class, pet subclass. */ Public classDogextendsPet {PrivateString strain;//Variety    /*** A method for constructing a parameter. * @paramName Nickname *@paramStrain Varieties*/     PublicDog (string name, string strain) {Super(name);  This. Strain =strain; }     PublicString Getstrain () {returnstrain; }    /*** Override the Print method of the parent class. */     Public voidprint () {Super. print ();//Call the Print method of the parent classSystem.out.println ("I am a" + This. Strain + ". "); }    /*** To achieve a meal method. */     Public voideat () {Super. Health =Super. Health + 3; System.out.println ("Dog" +Super. Name + "enough to eat!" Health value increased by 3. "); }}

Importjava.util.ArrayList;Importjava.util.List;ImportCn.jbit.epet.poly.Dog;/*** Test for list application generics*/ Public classtestlist { Public Static voidMain (string[] args) {/*1. Create Multiple Dog objects*/Dog Ououdog=NewDog ("Europe", "Shirley"); Dog Yayadog=NewDog ("Asia-Asia", "Labrador"); Dog Meimeidog=NewDog ("Meimei", "Shelly Rui")); Dog Feifeidog=NewDog ("Feifei", "Labrador"); /*2. Create ArrayList collection objects and put multiple dog objects into them*/List<Dog> dogs =NewArraylist<dog> ();//tag Element typeDogs.add (Ououdog);        Dogs.add (Yayadog);        Dogs.add (Meimeidog); Dogs.add (2, Feifeidog);//add Feifeidog to a specified location//dogs.add ("Hello");//A compilation error occurred and the element type is not dog.         /*3. Display information for the third element*/Dog Dog3= Dogs.get (2);//no type casts requiredSystem.out.println ("The third dog's message is as follows:")); System.out.println (Dog3.getname ()+ "\ T" +Dog3.getstrain ()); /*4. Using the foreach statement to traverse the Dogs object*/System.out.println ("\ nthe information for all dogs is as follows:");  for(Dog dog:dogs) {//no type casts requiredSystem.out.println (Dog.getname () + "\ T" +Dog.getstrain ()); }       }}

ImportJava.util.HashMap;ImportJava.util.Iterator;ImportJava.util.Map;ImportJava.util.Set;ImportCn.jbit.epet.poly.Dog;/*** Test apply generics to map * */ Public classTestMap { Public Static voidMain (string[] args) {/*1. Create Multiple Dog objects*/Dog Ououdog=NewDog ("Europe", "Shirley"); Dog Yayadog=NewDog ("Asia-Asia", "Labrador"); Dog Meimeidog=NewDog ("Meimei", "Shelly Rui")); Dog Feifeidog=NewDog ("Feifei", "Labrador"); /*2. Create a Map collection object and put multiple dog objects into it*/Map<String,Dog> dogmap=NewHashmap<string,dog>();        Dogmap.put (Ououdog.getname (), Ououdog);        Dogmap.put (Yayadog.getname (), Yayadog);        Dogmap.put (Meimeidog.getname (), Meimeidog);        Dogmap.put (Feifeidog.getname (), Feifeidog); /*3. Output the information of all the dogs in the collection by Iterators*/System.out.println ("Using iterator traversal, all dogs ' nicknames and breeds were:"); Set<String> Keys=dogmap.keyset ();//Take out the collection of all keysIterator<string> It=keys.iterator ();//get Iterator Object         while(It.hasnext ()) {String key=it.next ();//Remove KeyDog Dog=dogmap.get (key);//remove the corresponding value according to keySystem.out.println (key+ "\ T" +Dog.getstrain ()); }        /*//Use the foreach statement to output information for all dogs in the collection for (String Key:keys) {dog dog=dogmap.get (key);            Remove the corresponding value according to key System.out.println (key+ "\ T" +dog.getstrain ()); }*/            }}

27. Using Generic Collections