/*
* 有泛型的情况
* 使得程序具有更好的可读性和安全性
*/
private static void test1() throws Exception {
// 代码更具有可读性.
Generic<String> bc = new Generic();
String s = "OK";
File file = new File("e:/1.txt");
// 问题:在添加元素时,会检查错误,只可以向数组列表中添加指定类的对象.
bc.add(s);
// 由于加入的元素不是String类型,故报错.
// bc.add(file);//error The method add(String) in the type Generic<String> is not applicable
// for the arguments (File)
/*
* 不用强制转换
* 擦除get的返回类型后将返回Object类型.编译器自动插入String的强制类型转换.
* 也就说,编译器把这个方法调用翻译为两条虚拟机指令:
* 1.对原始方法get的调用.
* 2.将返回的Object类型强制转换为String类型.
*/
String s1 = bc.get(0);
}
/**
* An <b>opaque</b> class representing members of its enclosing <b>opaque</b> type.
*
* <p>Note that, this class is <b>opaque</b> but its constructors are all <b>internal</b>. This
* class and the subclasses of this class are used to declare either <b>opaque</b> <tt>public</tt>
* instance fields of the opaque type {@link js.Var.Member} or the <b>opaque</b> <tt>public</tt>
* static fields of other <b>opaque</b> types while their constructors are used to define the
* fields inside <b>opaque</b> classes. Under either circumstance, the field names must be exactly
* same as the member names, as the <b>opaque</b> fields of <b>opaque</b> types are resolved by
* re-compilers directly based on the field names.
*
* @author <a href="mailto:[email protected]">J.J.Liu (Jianjun Liu)</a> at <a
* href="http://www.jscripter.org" target="_blank">http://www.jscripter.org</a>
* @javascript <b>Opaque</b> types can be resolved but no class objects for them can be created in
* the target codes. Re-compilers must exit with error on operations accessing that kind of
* class objects. Re-compilers must resolve an <b>opaque</b> instance field declared by this
* class in {@link js.Var.Member} or its subclasses to the JavaScript identifier:
* <pre>q.m</pre>
* where <tt>m</tt> is the identifier of the field name and <tt>q</tt> is the identifier
* resolved from the instance of the enclosing member. Re-compilers must resolve an
* <b>opaque</b> static field declared by this class in <b>opaque</b> types other than {@link
* js.Var.Member} and its subclasses to the JavaScript identifier:
* <pre>m</pre>
* where <tt>m</tt> is the identifier of the field name. And re-compilers must report error on
* the access to <b>opaque</b> fields declared by this class under any other circumstances.
*/
public static class Member extends JsGlobal.RangeError.Prototype.Member {
/**
* Internally constructs a member based on a qualifying member.
*
* <p>This constructor is <b>internal</b> and only called inside of <b>opaque</b> or
* <b>internal</b> classes or class members.
*
* <p>Note that, this constructor is <b>internal</b> but its declaring class is <b>opaque</b>.
* This constructor is used to define <b>opaque</b> instance fields declared in the declaring
* class of this constructor itself or its subclasses. Under this circumstance, the field names
* must be exactly same as the member names, as the <b>opaque</b> instance fields of the
* <b>opaque</b> type {@link js.Var.Member} or its subclasses are resolved by re-compilers
* directly to their names appending to the name resolved from the specified qualifying member
* with a dot in between.
*
* @param q A qualifying member
* @param mid The ID of the member to construct
* @since 1.0
* @javascript Re-compilers must report error on the invocation to an <b>internal</b>
* constructor.
*/
public Member(JsObject.Member q, Mid mid) {
super(q, mid);
}
/**
* Internally constructs a member without a qualifying member.
*
* <p>This constructor is <b>internal</b> and only called inside of <b>opaque</b> or
* <b>internal</b> classes or class members.
*
* <p>Note that, this constructor is <b>internal</b> but its declaring class is <b>opaque</b>.
* This constructor is used to define <b>opaque</b> static fields, declared in <b>opaque</b>
* types other than the declaring class of this constructor itself and its subclasses. Under
* this circumstance, the field names must be exactly same as the member names, as the
* <b>opaque</b> static fields of <b>opaque</b> types are generally resolved by re-compilers
* directly to identifiers of their names.
*
* @param mid The ID of the member to construct
* @since 1.0
* @javascript Re-compilers must report error on the invocation to an <b>internal</b>
* constructor.
*/
public Member(Mid mid) {
super(mid);
}
/**
* Evaluates the property, represented by the current member instance, of the argument object.
*
* @param o The argument object
* @return The value of the current member based on the object argument.
* @since 1.0
* @javascript Re-compilers must convert the instance invocation of this method into the
* JavaScript expression:
* <pre>o.m</pre>
* where <tt>m</tt> is the identifier name resolved from the current member instance of the
* invocation.
*/
@Override
public JsRangeError with(ObjectLike o) {
return new JsRangeError(super.with(o));
}
/**
* An <b>opaque</b> instance field defining a sub-member that is named by the name of this
* field, qualified by the current member instance of the field, and to access the property of
* the name on an object.
*
* <p>The <tt>constructor</tt> property of an object is a reference to the function that was the
* constructor for that object.
*
* <p>A common use of the <tt>constructor</tt> property is to determine the type of unknown
* objects. Given an unknown value, you can use the {@link js.Js#typeof(Object)} operation to
* determine whether it is a primitive value or an object. If it is an object, you can use the
* <tt>constructor</tt> property to determine what type of object it is.
*
* <p>Note, however, that while this technique works for the objects built into core JavaScript,
* it is not guaranteed to work with host objects such as the <tt>window</tt> object of
* client-side JavaScript. The default implementation of the <tt>toString()</tt> method provides
* another way to determine the type of an unknown object.
*
* @since 1.0
* @javascript Re-compilers must resolve the member of this instance field to the identifier of
* the field name appending to the identifier resolved from its qualifying member with a dot
* in between.
*/
public final JsFunction.Member<JsRangeError> constructor =
new JsFunction.Member<JsRangeError>(
this, Members.constructor, Generic.get(JsRangeError.class));
}
/**
* An <b>opaque</b> class representing JavaScript <tt>RangeError</tt>.
*
* <p>An instance of the this class is thrown when a numeric value is not in its legal range. For
* example, setting the length of an array to a negative number causes a <tt>RangeError</tt> to be
* thrown.
*
* <p>In JS, to throw a value or object as a <tt>RuntimeException</tt>, see {@link
* js.Js#err(Object)}.
*
* @author <a href="mailto:[email protected]">J.J.Liu (Jianjun Liu)</a> at <a
* href="http://www.jscripter.org" target="_blank">http://www.jscripter.org</a>
* @see js.Js#err(Object)
* @javascript <b>Opaque</b> types can be resolved but no class objects for them can be generated
* into the target codes. Re-compilers must exit with error on the operations of accessing that
* kind of class objects. The <tt>checkcast</tt> operation to the class literal of this
* interface must be ignored and <tt>instanceof</tt> to it always <tt>true</tt>.
*/
public class JsRangeError extends JsGlobal.RangeError.Prototype {
/**
* An <b>opaque</b> class representing members of its enclosing <b>opaque</b> type.
*
* <p>Note that, this class is <b>opaque</b> but its constructors are all <b>internal</b>. This
* class and the subclasses of this class are used to declare either <b>opaque</b> <tt>public</tt>
* instance fields of the opaque type {@link js.Var.Member} or the <b>opaque</b> <tt>public</tt>
* static fields of other <b>opaque</b> types while their constructors are used to define the
* fields inside <b>opaque</b> classes. Under either circumstance, the field names must be exactly
* same as the member names, as the <b>opaque</b> fields of <b>opaque</b> types are resolved by
* re-compilers directly based on the field names.
*
* @author <a href="mailto:[email protected]">J.J.Liu (Jianjun Liu)</a> at <a
* href="http://www.jscripter.org" target="_blank">http://www.jscripter.org</a>
* @javascript <b>Opaque</b> types can be resolved but no class objects for them can be created in
* the target codes. Re-compilers must exit with error on operations accessing that kind of
* class objects. Re-compilers must resolve an <b>opaque</b> instance field declared by this
* class in {@link js.Var.Member} or its subclasses to the JavaScript identifier:
* <pre>q.m</pre>
* where <tt>m</tt> is the identifier of the field name and <tt>q</tt> is the identifier
* resolved from the instance of the enclosing member. Re-compilers must resolve an
* <b>opaque</b> static field declared by this class in <b>opaque</b> types other than {@link
* js.Var.Member} and its subclasses to the JavaScript identifier:
* <pre>m</pre>
* where <tt>m</tt> is the identifier of the field name. And re-compilers must report error on
* the access to <b>opaque</b> fields declared by this class under any other circumstances.
*/
public static class Member extends JsGlobal.RangeError.Prototype.Member {
/**
* Internally constructs a member based on a qualifying member.
*
* <p>This constructor is <b>internal</b> and only called inside of <b>opaque</b> or
* <b>internal</b> classes or class members.
*
* <p>Note that, this constructor is <b>internal</b> but its declaring class is <b>opaque</b>.
* This constructor is used to define <b>opaque</b> instance fields declared in the declaring
* class of this constructor itself or its subclasses. Under this circumstance, the field names
* must be exactly same as the member names, as the <b>opaque</b> instance fields of the
* <b>opaque</b> type {@link js.Var.Member} or its subclasses are resolved by re-compilers
* directly to their names appending to the name resolved from the specified qualifying member
* with a dot in between.
*
* @param q A qualifying member
* @param mid The ID of the member to construct
* @since 1.0
* @javascript Re-compilers must report error on the invocation to an <b>internal</b>
* constructor.
*/
public Member(JsObject.Member q, Mid mid) {
super(q, mid);
}
/**
* Internally constructs a member without a qualifying member.
*
* <p>This constructor is <b>internal</b> and only called inside of <b>opaque</b> or
* <b>internal</b> classes or class members.
*
* <p>Note that, this constructor is <b>internal</b> but its declaring class is <b>opaque</b>.
* This constructor is used to define <b>opaque</b> static fields, declared in <b>opaque</b>
* types other than the declaring class of this constructor itself and its subclasses. Under
* this circumstance, the field names must be exactly same as the member names, as the
* <b>opaque</b> static fields of <b>opaque</b> types are generally resolved by re-compilers
* directly to identifiers of their names.
*
* @param mid The ID of the member to construct
* @since 1.0
* @javascript Re-compilers must report error on the invocation to an <b>internal</b>
* constructor.
*/
public Member(Mid mid) {
super(mid);
}
/**
* Evaluates the property, represented by the current member instance, of the argument object.
*
* @param o The argument object
* @return The value of the current member based on the object argument.
* @since 1.0
* @javascript Re-compilers must convert the instance invocation of this method into the
* JavaScript expression:
* <pre>o.m</pre>
* where <tt>m</tt> is the identifier name resolved from the current member instance of the
* invocation.
*/
@Override
public JsRangeError with(ObjectLike o) {
return new JsRangeError(super.with(o));
}
/**
* An <b>opaque</b> instance field defining a sub-member that is named by the name of this
* field, qualified by the current member instance of the field, and to access the property of
* the name on an object.
*
* <p>The <tt>constructor</tt> property of an object is a reference to the function that was the
* constructor for that object.
*
* <p>A common use of the <tt>constructor</tt> property is to determine the type of unknown
* objects. Given an unknown value, you can use the {@link js.Js#typeof(Object)} operation to
* determine whether it is a primitive value or an object. If it is an object, you can use the
* <tt>constructor</tt> property to determine what type of object it is.
*
* <p>Note, however, that while this technique works for the objects built into core JavaScript,
* it is not guaranteed to work with host objects such as the <tt>window</tt> object of
* client-side JavaScript. The default implementation of the <tt>toString()</tt> method provides
* another way to determine the type of an unknown object.
*
* @since 1.0
* @javascript Re-compilers must resolve the member of this instance field to the identifier of
* the field name appending to the identifier resolved from its qualifying member with a dot
* in between.
*/
public final JsFunction.Member<JsRangeError> constructor =
new JsFunction.Member<JsRangeError>(
this, Members.constructor, Generic.get(JsRangeError.class));
}
/**
* Casts an <b>opaque</b> object to the current <b>opaque</b> type by wrapping it with the
* wrapping constructor.
*
* @param var The argument of an <b>opaque</b> object.
* @since 1.0
* @javascript Re-compilers must ignore the construction operation of this constructor, that is,
* replacing it with its only argument.
*/
public JsRangeError(JsObject var) {
super(var);
}
/**
* An <b>opaque</b> static field defining a member that is named by the field name without a
* qualifying member and to access the property of the name on an object.
*
* <p>The <tt>constructor</tt> property of an object is a reference to the function that was the
* constructor for that object.
*
* <p>A common use of the <tt>constructor</tt> property is to determine the type of unknown
* objects. Given an unknown value, you can use the {@link js.Js#typeof(Object)} operation to
* determine whether it is a primitive value or an object. If it is an object, you can use the
* <tt>constructor</tt> property to determine what type of object it is.
*
* <p>Note, however, that while this technique works for the objects built into core JavaScript,
* it is not guaranteed to work with host objects such as the <tt>window</tt> object of
* client-side JavaScript. The default implementation of the <tt>toString()</tt> method provides
* another way to determine the type of an unknown object.
*
* @since 1.0
* @javascript Re-compilers must resolve the member of this static field to the identifier of the
* field name.
*/
public static final JsFunction.Member<JsRangeError> constructor =
new JsFunction.Member<JsRangeError>(Members.constructor, Generic.get(JsRangeError.class));
/**
* Returns the primitive value associated with the current instance, if there is one. This
* invocation simply returns the instance itself for the current instance is an object and there
* is no primitive value for it.
*
* @return The current object itself.
* @since 1.0
* @javascript Re-compilers must convert the instance invocation of this method directly into a
* JavaScript invocation on its current object instance without changing the method name, but
* expanding variable arguments, if any, into comma-separated values.
*/
@Override
public JsRangeError valueOf() {
return new JsRangeError((JsObject) var().valueOf());
}
}