java 內部類和閉包
阿新 • • 發佈:2017-11-18
ice end trac 定義 stat 常見 tostring change wan
內部類(inner class)
public class Outer{ private String name; class Inner{ public String getOuterName(){ return Outer.this.name; } public void setOuterName(String name){ Outer.this.name = name; } } public static void main(String[] args){ Outer outer = new Outer(); Outer.Inner inner = outer.new Inner(); inner.setOuterName("wangtengfei"); System.out.println(inner.getOuterName()); } }
局部內部類
public class Outer{ private String name; private String sexual = "male"; class Inner1{ public String getOuterName(){ return Outer.this.name; } public void setOuterName(String name){ Outer.this.name = name; } } public void updateName(final String name,final String sexual){ class Inner2{ public void changeOuterInfo(){ Outer.this.name = name; Outer.this.sexual = sexual; } } Inner2 inner2 = new Inner2(); inner2.changeOuterInfo(); } public String getSexual(){ return sexual; } public static void main(String[] args){ Outer outer = new Outer(); Outer.Inner1 inner = outer.new Inner1(); inner.setOuterName("wangtengfei"); System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual()); outer.updateName("Iris","female"); System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual()); } }
靜態內部類
public class Outer{ private String name; private String sexual = "male"; public static int count; public Outer(){ count++; } class Inner1{ public String getOuterName(){ return Outer.this.name; } public void setOuterName(String name){ Outer.this.name = name; } } public void updateName(final String name,final String sexual){ class Inner2{ public void changeOuterInfo(){ Outer.this.name = name; Outer.this.sexual = sexual; } } Inner2 inner2 = new Inner2(); inner2.changeOuterInfo(); } public String getSexual(){ return sexual; } public static class Inner3{ public String getOuterInstanceCount(){ return "there are "+Outer.count+" Outer instances have been created"; } } public static void main(String[] args){ Outer outer = new Outer(); Outer.Inner1 inner = outer.new Inner1(); inner.setOuterName("wangtengfei"); System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual()); outer.updateName("Iris","female"); System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual()); Inner3 inner3 = new Inner3(); System.out.println(inner3.getOuterInstanceCount()); } }
匿名內部類
public class Outer{
private String name;
private String sexual = "male";
public static int count;
public Outer(){
count++;
}
class Inner1{
public String getOuterName(){
return Outer.this.name;
}
public void setOuterName(String name){
Outer.this.name = name;
}
}
public void updateName(final String name,final String sexual){
class Inner2{
public void changeOuterInfo(){
Outer.this.name = name;
Outer.this.sexual = sexual;
}
}
Inner2 inner2 = new Inner2();
inner2.changeOuterInfo();
}
public String getSexual(){
return sexual;
}
public static class Inner3{
public String getOuterInstanceCount(){
return "there are "+Outer.count+" Outer instances have been created";
}
}
public void showTime(){
Thread t = new Thread(new Runnable() {
public void run() {
int time = 60;
int i = 0;
while(i< time){
System.out.println(Thread.currentThread().toString());
System.out.println((new Date(System.currentTimeMillis())).toString());
i+=5;
try {
Thread.sleep(5*1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});
ExecutorService executorService = Executors.newCachedThreadPool();
executorService.execute(t);
executorService.execute(t);
}
public static void main(String[] args){
Outer outer = new Outer();
Outer.Inner1 inner = outer.new Inner1();
inner.setOuterName("wangtengfei");
System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());
outer.updateName("Iris","female");
System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());
Inner3 inner3 = new Inner3();
System.out.println(inner3.getOuterInstanceCount());
outer.showTime();
System.out.println("main process end!");
}
}
回調(callbacks)和閉包(closure)
函數式編程中常見的概念,內部作用域中調用定義它的外部作用域中的成員或者方法。示例,在局部內部類Inner2的changeOuterInfo()方法中調用外部Outer類的showTime()方法,註意調用方式(Outer.this.showTime())
public class Outer{
private String name;
private String sexual = "male";
public static int count;
public Outer(){
count++;
}
class Inner1{
public String getOuterName(){
return Outer.this.name;
}
public void setOuterName(String name){
Outer.this.name = name;
}
}
public void updateName(final String name,final String sexual){
class Inner2{
public void changeOuterInfo(){
Outer.this.name = name;
Outer.this.sexual = sexual;
Outer.this.showTime();
}
}
Inner2 inner2 = new Inner2();
inner2.changeOuterInfo();
}
public String getSexual(){
return sexual;
}
public static class Inner3{
public String getOuterInstanceCount(){
return "there are "+Outer.count+" Outer instances have been created";
}
}
public void showTime(){
Thread t = new Thread(new Runnable() {
public void run() {
int time = 60;
int i = 0;
while(i< time){
System.out.println(Thread.currentThread().toString());
System.out.println((new Date(System.currentTimeMillis())).toString());
i+=5;
try {
Thread.sleep(5*1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});
ExecutorService executorService = Executors.newCachedThreadPool();
executorService.execute(t);
executorService.execute(t);
}
public static void main(String[] args){
Outer outer = new Outer();
Outer.Inner1 inner = outer.new Inner1();
inner.setOuterName("wangtengfei");
System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());
outer.updateName("Iris","female");
System.out.println("Name:"+inner.getOuterName()+",sexual:"+outer.getSexual());
Inner3 inner3 = new Inner3();
System.out.println(inner3.getOuterInstanceCount());
// outer.showTime();
System.out.println("main process end!");
}
}
java 內部類和閉包