When creating object from static method: Cannot find default value for object

[Matt Bateman]

I'm using Rhino 1.7.6 with JDK 8. I want to create an object in javascript using a static method on another object. When I try to call any functions on the created object, I get "Cannot find default value for object".

The javascript:

var user = UserService.getUser(123);

java.lang.System.out.println(user);
java.lang.System.out.println(user.getEmail());

Calling "println" with the "user" object correctly calls the "toString" method on the object. Calling "getEmail" throws the above mentioned error.

If I do this:

var user = new User();
java.lang.System.out.println(user.getEmail());

it works just fine.

So it seems to me that I'm not doing something right when creating the "user" object via the static method on UserService. Any suggestions?

The bootstrap code:

String source = "sdi.js";

Context ctx = Context.enter();

try (Reader in = new FileReader(source)) {

    ctx.setLanguageVersion(Context.VERSION_1_8);

    Scriptable scope = ctx.initStandardObjects();

    ScriptableObject.defineClass(scope, UserService.class);

    ScriptableObject.defineClass(scope, User.class);

    Object ob = ctx.evaluateReader(scope, in, source, 1, null);

}

finally {

    Context.exit();

}

The User code:

public class User extends ScriptableObject {

    private int mId;

    private String mEmail;

    private String mUsername;

    @JSConstructor

    public User() {}

    @JSConstructor

    public User(int id, String email, String username) {

        mId = id;

        mEmail = email;

        mUsername = username;

    }

    @Override

    public String getClassName() {

        return "User";

    }

    @JSFunction

    public int getId() {

        return mId;

    }

    public void setId(int id) {

        mId = id;

    }

    @JSFunction

    public String getEmail() {

        return mEmail;

    }

    public void setEmail(String email) {

        mEmail = email;

    }

    @JSFunction

    public String getUsername() {

        return mUsername;

    }

    public void setUsername(String name) {

        mUsername = name;

    }

    @Override

    public String toString() {

        StringBuilder buf = new StringBuilder();

        buf.append("[ id = '").append(mId).append("', email = '").append(mEmail).append("', user = '").append(mUsername).append("' ]");

        return buf.toString();

    }

}

The "UserService" code:

public class UserService extends ScriptableObject {

    @JSConstructor

    public UserService() {}

    @Override

    public String getClassName() {

        return "UserService";

    }

    @JSStaticFunction

    public static User getUser(int id) {

        return new User(id, "f...@bar.com", "matt");

    }

}

[Evgeny Shepelyuk]

You should create new instance using Context.newObject.
See http://www-archive.mozilla.org/rhino/apidocs/org/mozilla/javascript/Context.html#newObject(org.mozilla.javascript.Scriptable, java.lang.String, java.lang.Object[])

[Matt Bateman]

It took some time for me to figure out what you suggested but I did and it works. For anyone else that finds this post the solution was to create the new object using the Context instance inside the java code. I changed the "UserService" code to the below and it worked nicely.

Scriptable s = mCtx.newObject(mScope, "User");

User user = (User) s;

user.setId(id);

user.setEmail("f...@bar.com");

user.setUsername("matt");

return user;

[Evgeny Shepelyuk]

In fact, I believe you could achieve the same by no implementing Rhino Host objects, i.e. without extending Scriptable and annotating method.

But instead try to create simple java classes and use them directly in your script.

вівторок, 5 травня 2015 р. 01:44:40 UTC+3 користувач Matt Bateman написав: