在Rhino中将宿主对象返回JavaScript的最佳方法是什么?我有两个这样的课程:
public class Hosted extends org.mozilla.javascript.ScriptableObject {
private static final long serialVersionUID = 1;
public Hosted() {}
public void jsConstructor() {}
public String getClassName() {
return "Hosted";
}
public Member jsGet_member() {
Member m = new Member();
m.defineFunctionProperties(new String[] { "toString" }, m.getClass(), DONTENUM);
return m;
}
}
public class Member extends org.mozilla.javascript.ScriptableObject {
private static final long serialVersionUID = 2;
public Member() {}
public void jsConstructor() {}
public String getClassName() {
return "Member";
}
public String toString() {
return "called toString()";
}
}
从我可以调用toString方法的意义上讲,它是有效的,但是成员对象的行为不符合我的预期:
js> defineClass("Hosted");
js> defineClass("Member");
js> var h = new Hosted();
js> h.toString();
[object Hosted]
js> h instanceof Hosted;
true
js> h.__proto__;
[object Hosted]
js>
js> var m = h.member;
js> m.toString();
called toString()
js> m instanceof Member; // Should be true
false
js> m.__proto__; // Should be [object Member]
null
如果我调用Object.prototype.toString,它会说这是一个Member对象:
js> Object.prototype.toString.call(m);
[object Member]
我试过调用m.setPrototype和Context.javaToJS.
解决方法:
public Scriptable jsGet_member() {
Scriptable scope = ScriptableObject.getTopLevelScope(this);
Member m = new Member();
m.setParentScope(scope);
// defineClass("Member") must have previously been called.
m.setPrototype(ScriptableObject.getClassPrototype(scope, "Member"));
m.defineFunctionProperties(new String[] { "toString" },
m.getClass(), DONTENUM);
return m;
}
js> defineClass("Member")
js> defineClass("Hosted")
js> var h = new Hosted();
js> var m = h.member;
js> m.toString();
called toString()
js> m instanceof Member;
true
js> m.__proto__;
[object Member]
编辑:该方法也可以编写为:
public Scriptable jsGet_member() {
Scriptable scope = ScriptableObject.getTopLevelScope(this);
Context cx = Context.getCurrentContext();
Member m = (Member)cx.newObject(scope, "Member");
m.defineFunctionProperties(new String[] { "toString" },
m.getClass(), DONTENUM);
return m;
}
它将调用Member.jsConstructor;可能还有其他差异.