PrimitiveWrapFactory.java

/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

import org.mozilla.javascript.Context;
import org.mozilla.javascript.Scriptable;
import org.mozilla.javascript.WrapFactory;

/**
 * An example WrapFactory that can be used to avoid wrapping of Java types that can be converted to
 * ECMA primitive values. So java.lang.String is mapped to ECMA string, all java.lang.Numbers are
 * mapped to ECMA numbers, and java.lang.Booleans are mapped to ECMA booleans instead of being
 * wrapped as objects. Additionally java.lang.Character is converted to ECMA string with length 1.
 * Other types have the default behavior.
 *
 * <p>Note that calling "new java.lang.String('foo')" in JavaScript with this wrap factory enabled
 * will still produce a wrapped Java object since the WrapFactory.wrapNewObject method is not
 * overridden.
 *
 * <p>The PrimitiveWrapFactory is enabled on a Context by calling setWrapFactory on that context.
 */
public class PrimitiveWrapFactory extends WrapFactory {

    @Override
    public Object wrap(Context cx, Scriptable scope, Object obj, Class<?> staticType) {
        if (obj instanceof String || obj instanceof Number || obj instanceof Boolean) {
            return obj;
        } else if (obj instanceof Character) {
            char[] a = {((Character) obj).charValue()};
            return new String(a);
        }
        return super.wrap(cx, scope, obj, staticType);
    }
}