ACDK基于C++的模型(基本类型、接口、对象类,数组,异常,枚举和命名空间)组织了自己的类型模型。
1、基本模型
基本类型 Object对象封装 位数(bit)
bool Boolean 8
char Character 8
uc2char UnicodeCharacter 16
uc4char UnicodeCharacter 23
byte Byte 8
short Short 16
int Integer 32
jlong Long 64
float Float 32
double Double 64
2、Enum类型
使用C++的enum,假如需要考虑ACDK的元编译,需要使用宏:ACDK_DECL_ENUM,用来提供元信息。动态库需要导出类型的时候,使用ACDK_DEF_LIB_ENUM。不牵扯到元信息的Enum类型可以在定义的时候使用foreign关键字。
3、对象类型
必须直接或者间接从Object派生
// declare the R-type RLegalAcdkClass
// and the Array type LegalAcdkClassArray and RLegalAcdkClassArray
ACDK_DECL_CLASS(LegalAcdkClass);
// The class itself:
class LegalAcdkClass : extends acdk::lang::Object // extend the Object class
{
ACDK_WITH_METAINFO(LegalAcdkClass); // optional, for class information see Metainfo
private:
RString message;
public:
// constructor
LegalAcdkClass() : Object() , message("")
{
}
// a method
RString getMessage()
{
return message;
}
};
不能多继承类,但是可以提供一种更好的办法就是多继承接口。
// declare the R-type RLegalAcdkClass
// and the Array type LegalAcdkClassArray and RLegalAcdkClassArray
ACDK_DECL_CLASS(LegalAcdkClass);
// The class itself:
class LegalAcdkClass : extends acdk::lang::Object // extend the Object class
, implements acdk::lang::Comparable // implements the interface
{
ACDK_WITH_METAINFO(LegalAcdkClass) // optional, for class information see Metainfo
private:
RString message;
public:
// implement the Comparable interface method
int compareTo(IN(RObject) other)
{
return getMessage()->compareTo(RLegalAcdkClass(other)->getMessage());
}
RString getMessage() { return message; }
};
Class信息
RStringBuffer sb1 = new StringBuffer("ACDK");
RStringBuffer sb2 = new StringBuffer("JAVA");
RClass cls1 = sb1->getClass();
RClass cls2 = sb2->getClass();
assert(cls1 == cls2); // always true
你可以定义不符合acdk规范的类型已经结构等,但是会失去acdk提供的一些特性。
ACDK的异常捕获需要注意:
void foo()
{
try {
} catch (acdk::io::RIOException ex) {
// handle here type of IOException.
} catch (RThrowable ex) {
// handle all other ACDK exceptions
}
/**//* DONT DO THAT
otherwise Nullpointer exception will not handled properly
} catch () {
// this are not ACDK exception
// for example std::exception, if you use STL
}
*/
}
方法参数缺省传递方式是:
a、基本类型(int,float,char,etc)按值传递
b、enum按值
c、类和接口按引用传递
d、数组按引用传递
参数的in,out,inout
void foo(IN(RStringBuffer) buffer, int len)
{
//buffer = new StringBuffer(); // caller not be effected, RStringBuffer isn't changed
buffer->append("asdf"); // caller be effected.
len = 42; // caller not be effected
}
// is equivalent to
//void foo(RStringBuffer buffer, int len);
void use_foo()
{
RStringBuffer sb = new StringBuffer("");
RStringBuffer sbs = sb;
int value = 1000;
foo(sb, value);
//value == 1000 && sb == sbs
// sb->toString() == "ACDK"
}
in参数确保对象引用不会变化;可以传递栈对象
void foo(OUT(RStringBuffer) buffer, OUT(int) len)
{
// buffer is unitialized here
buffer = new StringBuffer(1024);
// buffer is now initialed;
buffer->append("ACDK");
len = buffer->length();
}
RString use_foo()
{
RStringBuffer sb;
int len;
foo(sb, len);
System::out->println("Buffer is [" + sb->toString() + "] len = " + len);
return sb->toString();
}
使用out参数,按照引用传参,可以修改传入参数,但是对于进程间不可以传递栈对象。
posted on 2007-12-25 12:24
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