final String signature, final String superName,
final String[] interfaces) {
String enhancedName = name + "$EnhancedByASM"; //改變類命名
enhancedSuperName = name; //改變父類，這里是”Account”
super.visit(version, access, enhancedName, signature,
enhancedSuperName, interfaces);
}
改進 visitMethod 方法，增加對構造函數的處理：
public MethodVisitor visitMethod(final int access, final String name,
final String desc, final String signature, final String[] exceptions) {
MethodVisitor mv = cv.visitMethod(access, name, desc, signature, exceptions);
MethodVisitor wrappedMv = mv;
if (mv != null) {
if (name.equals("operation")) {
wrappedMv = new AddSecurityCheckMethodAdapter(mv);
} else if (name.equals("<init>")) {
wrappedMv = new ChangeToChildConstructorMethodAdapter(mv,
enhancedSuperName);
}
}
return wrappedMv;
}
這里 ChangeToChildConstructorMethodAdapter 將負責把 Account 的構造函數改造成其子類 Account$EnhancedByASM 的構造函數
Account$EnhancedByASM 的構造函數：
class ChangeToChildConstructorMethodAdapter extends MethodAdapter {
private String superClassName;
public ChangeToChildConstructorMethodAdapter(MethodVisitor mv,
String superClassName) {
super(mv);
this.superClassName = superClassName;
}
public void visitMethodInsn(int opcode, String owner, String name,
String desc) {
//調用父類的構造函數時
if (opcode == Opcodes.INVOKESPECIAL && name.equals("<init>")) {
owner = superClassName;
}
super.visitMethodInsn(opcode, owner, name, desc);//改寫父類為superClassName
}
}
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