SoloMapComponentReplacePolicy.java 文件源码

/**
 * @return true if the object can be added to the MapHandler, and
 *         will have removed the previous duplicate from the
 *         MapHandler.
 */
public boolean canAdd(BeanContextSupport bc, Object obj)
        throws MultipleSoloMapComponentException {

    if (obj == null) {
        return false;
    }

    // At first we just added the new item, but we should remove
    // the previous one, too.
    if (obj instanceof SoloMapComponent) {
        Class firstClass = obj.getClass();
        for (Iterator it = bc.iterator(); it.hasNext();) {
            Object someObj = it.next();
            if (someObj instanceof SoloMapComponent) {
                Class secondClass = someObj.getClass();

                if (firstClass == secondClass
                        || firstClass.isAssignableFrom(secondClass)
                        || secondClass.isAssignableFrom(firstClass)) {

                    bc.remove(someObj);
                    break;
                }
            }
        }
    }

    return true;
}