Attr的visitNewClass()方法解读
在visitNewClass()方法中有如下注释：
We are seeing an anonymous class instance creation.
In this case, the class instance creation expression
E.new <typeargs1>C<typargs2>(args) { ... }
is represented internally as
E . new <typeargs1>C<typargs2>(args) ( class <empty-name> { ... } ) .
This expression is then *transformed* as follows:
(1) add a STATIC flag to the class definition if the current environment is static
(2) add an extends or implements clause
(3) add a constructor.
For instance, if C is a class, and ET is the type of E, the expression
E.new <typeargs1>C<typargs2>(args) { ... }
is translated to (where X is a fresh name and typarams is the
parameter list of the super constructor):
new <typeargs1>X(<*nullchk*>E, args)
where
X extends C<typargs2> {
<typarams> X(ET e, args) {
e.<typeargs1>super(args)
}
...
}
举个例子，如下：
class E{
class C<T1>{
// C的构造函数
public <T2> C(){ }
public void t(){
E e = new E();
e.new <String>C<Integer>(){};
}
}
}
按如上的描述，应该被改写为：
class E{
class C<T1>{
// C的构造函数
public <T2> C(){ }
public void t(){
E e = new E();
new <String>X(e); // 更改为了这样的形式
}
}
}
class X extends E.C<Integer>{
<T2> X(E e){
e.<T2>super();
}
}
传入visitNewClass()方法的tree参数如下截图。
通过调用visitNewClass()方法后，e.new <String>C<Integer>(){}方法被改写为：
new <String>C<Integer>(e<*nullchk*>){
<T2 extends java.lang.Object>(com.test19.E x0) {
x0.<T2>super();
}
}
编译后生成3个Class文件，如下：
（1）E.class，通过调用Attr类的visitNewClass()方法后，e.new <String>C<Integer>(){}方法被改写为：
class E {
E() {
super();
}
class C<T1> {
public <T2>C() {
super();
}
public void t() {
E e = new E();
new <String>C<Integer>(e<*nullchk*>){
<T2 extends .java.lang.Object>(.com.test19.E x0) {
x0.<T2>super();
}
};
}
}
}
最终的字节码如下：
class com.test19.E
SourceFile: "Test07.java"
InnerClasses:
#5= #4 of #2; //C=class com/test19/E$C of class com/test19/E
minor version: 0
major version: 51
flags: ACC_SUPER
Constant pool:
#1 = Methodref #3.#16 // java/lang/Object."<init>":()V
#2 = Class #17 // com/test19/E
#3 = Class #18 // java/lang/Object
#4 = Class #19 // com/test19/E$C
#5 = Utf8 C
#6 = Utf8 InnerClasses
#7 = Utf8 <init>
#8 = Utf8 ()V
#9 = Utf8 Code
#10 = Utf8 LineNumberTable
#11 = Utf8 LocalVariableTable
#12 = Utf8 this
#13 = Utf8 Lcom/test19/E;
#14 = Utf8 SourceFile
#15 = Utf8 Test07.java
#16 = NameAndType #7:#8 // "<init>":()V
#17 = Utf8 com/test19/E
#18 = Utf8 java/lang/Object
#19 = Utf8 com/test19/E$C
{
com.test19.E();
flags:
Code:
stack=1, locals=1, args_size=1
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: return
LineNumberTable:
line 4: 0
line 5: 4
LocalVariableTable:
Start Length Slot Name Signature
0 5 0 this Lcom/test19/E;
}
（2）E$C通过调用desugar类后如下：
class E$C {
/*synthetic*/ final E this$0;
public E$C(/*synthetic*/ final E this$0) {
this.this$0 = this$0;
super();
}
public void t() {
E e = new E();
new <String>E$C$1(this, e<*nullchk*>);
}
}
最终的字节码如下：
class com.test19.E$C<T1 extends java.lang.Object> extends java.lang.Object
Signature: #29 // <T1:Ljava/lang/Object;>Ljava/lang/Object;
SourceFile: "Test07.java"
InnerClasses:
#10= #8 of #3; //C=class com/test19/E$C of class com/test19/E
#5; //class com/test19/E$C$1
minor version: 0
major version: 51
flags: ACC_SUPER
Constant pool:
#1 = Fieldref #8.#32 // com/test19/E$C.this$0:Lcom/test19/E;
#2 = Methodref #9.#33 // java/lang/Object."<init>":()V
#3 = Class #34 // com/test19/E
#4 = Methodref #3.#33 // com/test19/E."<init>":()V
#5 = Class #35 // com/test19/E$C$1
#6 = Methodref #9.#36 // java/lang/Object.getClass:()Ljava/lang/Class;
#7 = Methodref #5.#37 // com/test19/E$C$1."<init>":(Lcom/test19/E$C;Lcom/test19/E;)V
#8 = Class #38 // com/test19/E$C
#9 = Class #39 // java/lang/Object
#10 = Utf8 C
#11 = Utf8 InnerClasses
#12 = Utf8
#13 = Utf8 this$0
#14 = Utf8 Lcom/test19/E;
#15 = Utf8 <init>
#16 = Utf8 (Lcom/test19/E;)V
#17 = Utf8 Code
#18 = Utf8 LineNumberTable
#19 = Utf8 LocalVariableTable
#20 = Utf8 this
#21 = Utf8 Lcom/test19/E$C;
#22 = Utf8 LocalVariableTypeTable
#23 = Utf8 Lcom/test19/E$C<TT1;>;
#24 = Utf8 Signature
#25 = Utf8 <T2:Ljava/lang/Object;>()V
#26 = Utf8 t
#27 = Utf8 ()V
#28 = Utf8 e
#29 = Utf8 <T1:Ljava/lang/Object;>Ljava/lang/Object;
#30 = Utf8 SourceFile
#31 = Utf8 Test07.java
#32 = NameAndType #13:#14 // this$0:Lcom/test19/E;
#33 = NameAndType #15:#27 // "<init>":()V
#34 = Utf8 com/test19/E
#35 = Utf8 com/test19/E$C$1
#36 = NameAndType #40:#41 // getClass:()Ljava/lang/Class;
#37 = NameAndType #15:#42 // "<init>":(Lcom/test19/E$C;Lcom/test19/E;)V
#38 = Utf8 com/test19/E$C
#39 = Utf8 java/lang/Object
#40 = Utf8 getClass
#41 = Utf8 ()Ljava/lang/Class;
#42 = Utf8 (Lcom/test19/E$C;Lcom/test19/E;)V
{
final com.test19.E this$0;
flags: ACC_FINAL, ACC_SYNTHETIC
public <T2 extends java/lang/Object> com.test19.E$C();
flags: ACC_PUBLIC
Code:
stack=2, locals=2, args_size=2
0: aload_0
1: aload_1
2: putfield #1 // Field this$0:Lcom/test19/E;
5: aload_0
6: invokespecial #2 // Method java/lang/Object."<init>":()V
9: return
LineNumberTable:
line 7: 0
LocalVariableTable:
Start Length Slot Name Signature
0 10 0 this Lcom/test19/E$C;
LocalVariableTypeTable:
Start Length Slot Name Signature
0 10 0 this Lcom/test19/E$C<TT1;>;
Signature: #25 // <T2:Ljava/lang/Object;>()V
public void t();
flags: ACC_PUBLIC
Code:
stack=5, locals=2, args_size=1
0: new #3 // class com/test19/E
3: dup
4: invokespecial #4 // Method com/test19/E."<init>":()V
7: astore_1
8: new #5 // class com/test19/E$C$1
11: dup
12: aload_0
13: aload_1
14: dup
15: invokevirtual #6 // Method java/lang/Object.getClass:()Ljava/lang/Class;
18: pop
19: invokespecial #7 // Method com/test19/E$C$1."<init>":(Lcom/test19/E$C;Lcom/test19/E;)V
22: pop
23: return
LineNumberTable:
line 10: 0
line 11: 8
line 12: 23
LocalVariableTable:
Start Length Slot Name Signature
0 24 0 this Lcom/test19/E$C;
8 16 1 e Lcom/test19/E;
LocalVariableTypeTable:
Start Length Slot Name Signature
0 24 0 this Lcom/test19/E$C<TT1;>;
}
（3）E$C$1通过调用desugar类后代码如下：
class E$C$1 extends com.test19.E$C {
/*synthetic*/ final E$C this$1;
E$C$1(/*synthetic*/ final E$C this$1, com.test19.E x0) {
this.this$1 = this$1;
<T2>super(x0<*nullchk*>);
}
}
最终编译后的字节码如下：
class com.test19.E$C$1 extends com.test19.E$C<java.lang.Integer>
Signature: #23 // Lcom/test19/E$C<Ljava/lang/Integer;>;
SourceFile: "Test07.java"
EnclosingMethod: #5.#27 // com.test19.E$C.t
InnerClasses:
#7= #5 of #33; //C=class com/test19/E$C of class com/test19/E
#4; //class com/test19/E$C$1
minor version: 0
major version: 51
flags: ACC_SUPER
Constant pool:
#1 = Fieldref #4.#28 // com/test19/E$C$1.this$1:Lcom/test19/E$C;
#2 = Methodref #29.#30 // java/lang/Object.getClass:()Ljava/lang/Class;
#3 = Methodref #5.#31 // com/test19/E$C."<init>":(Lcom/test19/E;)V
#4 = Class #32 // com/test19/E$C$1
#5 = Class #34 // com/test19/E$C
#6 = Utf8 this$1
#7 = Utf8 C
#8 = Utf8 InnerClasses
#9 = Utf8 Lcom/test19/E$C;
#10 = Utf8 <init>
#11 = Utf8 (Lcom/test19/E$C;Lcom/test19/E;)V
#12 = Utf8 Code
#13 = Utf8 LineNumberTable
#14 = Utf8 LocalVariableTable
#15 = Utf8 this
#16 = Utf8
#17 = Utf8 Lcom/test19/E$C$1;
#18 = Utf8 x0
#19 = Utf8 Lcom/test19/E;
#20 = Utf8 LocalVariableTypeTable
#21 = Utf8 Lcom/test19/E$C.1;
#22 = Utf8 Signature
#23 = Utf8 Lcom/test19/E$C<Ljava/lang/Integer;>;
#24 = Utf8 SourceFile
#25 = Utf8 Test07.java
#26 = Utf8 EnclosingMethod
#27 = NameAndType #35:#36 // t:()V
#28 = NameAndType #6:#9 // this$1:Lcom/test19/E$C;
#29 = Class #37 // java/lang/Object
#30 = NameAndType #38:#39 // getClass:()Ljava/lang/Class;
#31 = NameAndType #10:#40 // "<init>":(Lcom/test19/E;)V
#32 = Utf8 com/test19/E$C$1
#33 = Class #41 // com/test19/E
#34 = Utf8 com/test19/E$C
#35 = Utf8 t
#36 = Utf8 ()V
#37 = Utf8 java/lang/Object
#38 = Utf8 getClass
#39 = Utf8 ()Ljava/lang/Class;
#40 = Utf8 (Lcom/test19/E;)V
#41 = Utf8 com/test19/E
{
final com.test19.E$C this$1;
flags: ACC_FINAL, ACC_SYNTHETIC
com.test19.E$C$1(com.test19.E$C, com.test19.E);
flags:
Code:
stack=3, locals=3, args_size=3
0: aload_0
1: aload_1
2: putfield #1 // Field this$1:Lcom/test19/E$C;
5: aload_0
6: aload_2
7: dup
8: invokevirtual #2 // Method java/lang/Object.getClass:()Ljava/lang/Class;
11: pop
12: invokespecial #3 // Method com/test19/E$C."<init>":(Lcom/test19/E;)V
15: return
LineNumberTable:
line 11: 0
LocalVariableTable:
Start Length Slot Name Signature
0 16 0 this Lcom/test19/E$C$1;
0 16 2 x0 Lcom/test19/E;
LocalVariableTypeTable:
Start Length Slot Name Signature
0 16 0 this Lcom/test19/E$C.1;
}
Attr的visitNewClass()方法解读的更多相关文章
- jQuery操纵DOM元素属性 attr()和removeAtrr()方法使用详解
jQuery操纵DOM元素属性 attr()和removeAtrr()方法使用详解 jQuery中操纵元素属性的方法: attr(): 读或者写匹配元素的属性值. removeAttr(): 从匹配的 ...
- jquery中dom元素的attr和prop方法的理解
一.背景 在编写使用高版本[ jQuery 1.6 开始新增了一个方法 prop()]的jquery插件进行编写js代码的时候,经常不知道dom元素的attr和prop方法到底有什么区别?各自有什么应 ...
- input是否checked与使用jquery的attr或prop方法无关
最近在项目中有这样一个需求,用户在下单时可以选择优惠券,也可取消选择,并且可以多次选择,取消. 这是一个典型的input标签checked功能,博主使用radio元素实现此需求,但是优惠券只能选中,不 ...
- Connection 对象简介 方法解读 JDBC简介（四）
通过驱动管理器DriverManager的getConnection方法,可以创建到指定URL的连接 Connection conn = DriverManager.getConnection ...
- jQuery .attr()和.removeAttr()方法操作元素属性示例
今天主要和大家一起分享一下如何使用jQuery的.attr()和.removeAttr()方法读取,添加,修改,删除元素的属性.大家在平时的Web页面制作中都有碰到如何动态的获取元素的属性和属性值,或 ...
- jQuery中attr和prop方法的区别
jQuery中attr和prop方法的区别。 http://my.oschina.net/bosscheng/blog/125833 http://www.javascript100.com/?p=8 ...
- $().attr()的使用方法 && $().html()与$().text()的差别
<1>$().attr()的使用方法 </pre><pre class="html" name="code"><htm ...
- Java安全之原生readObject方法解读
Java安全之原生readObject方法解读 0x00 前言 在上篇文章分析shiro中,遇到了Shiro重写了ObjectInputStream的resolveClass导致的一些基于Invoke ...
- jQuery 中 attr() 和 prop() 方法的区别
前几天,有人给 Multiple Select 插件 提了问题: setSelects doesn't work in Firefox when using jquery 1.9.0 一直都在用 jQ ...
随机推荐
- MFCC
在语音识别研究领域,音频特征的选择至关重要.在这里介绍一种非常成功的音频特征——Mel Frequency Cepstrum Coefficient(MFCC),中文名字为梅尔频率倒谱系数.MFCC特 ...
- pyquery 安装
取得网页源代码,导入pyquery库 pip3 install pyquery 如果报错的话:python安装pyquery报错error: 'libxml/xmlversion.h' f ...
- day27(反射之内省机制实现BeanUtils)
使用内省方式来实现beanUtils往对象里面存值 public class BeanInfoUtil2 { public static void setPropertyByIntrospector( ...
- （区间dp + 记忆化搜索)Treats for the Cows （POJ 3186）
http://poj.org/problem?id=3186 Description FJ has purchased N (1 <= N <= 2000) yummy treats ...
- android 线程中断的处理
android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@4 ...
- hdu 1695 GCD 【莫比乌斯函数】
题目大意:给你 a , b , c , d , k 五个值 (题目说明了 你可以认为 a=c=1) x 属于 [1,b] ,y属于[1,d] 让你求有多少对这样的 (x,y)满足gcd(x,y)= ...
- TryEnterCriticalSection___Delphi
VOID EnterCriticalSection:非阻塞函数.将当前线程对指定临界区的引用计数减1:在使用计数变为零时,另一等待此临界区的一个线程将被唤醒. BOOL TryEnterCritica ...
- Tencent interview
1.常见的聚类算法 1):划分法:k-means 2):基于密度的方法: 2.EM 算法 EM算法是在概率模型中寻找参数的最大似然估计或者最大后验概率的算法,其中概率模型依赖于无法观测的隐藏变量.EM ...
- mysql命令行客户端结果分页浏览
转载请注明出处:http://xiezhenye.com/2008/06/mysql%e5%91%bd%e4%bb%a4%e8%a1%8c%e5%ae%a2%e6%88%b7%e7%ab%af%e7% ...
- 记Asp.Net Core Swagger 使用 并带域接口处理
引用作者原话:Asp.Net的WebApi中使用Swagger作为说明和测试的页面是非常不错的,比起WebApiTestClient来至少在界面上的很大的提升.但是使用Swagger时如果只是一般的控 ...