private String contrast() {
        final ResourceDO before = (ResourceDO) getBefore();
        Objects.requireNonNull(before);
        final ResourceDO after = (ResourceDO) getAfter();
        Objects.requireNonNull(after);
        if (Objects.equals(before, after)) {
            return "it no change";
        }
        final StringBuilder builder = new StringBuilder();
        if (!Objects.equals(before.getName(), after.getName())) {
            builder.append(String.format("name[%s => %s] ", before.getName(), after.getName()));
        }
        if (!Objects.equals(before.getComponent(), after.getComponent())) {
            builder.append(String.format("component[%s => %s] ", before.getComponent(), after.getComponent()));
        }
        if (!Objects.equals(before.getIcon(), after.getIcon())) {
            builder.append(String.format("match icon[%s => %s] ", before.getIcon(), after.getIcon()));
        }
        if (!Objects.equals(before.getTitle(), after.getTitle())) {
            builder.append(String.format("title[%s => %s] ", before.getTitle(), after.getTitle()));
        }
        if (!Objects.equals(before.getSort(), after.getSort())) {
            builder.append(String.format("sort[%s => %s] ", before.getSort(), after.getSort()));
        }
        if (!Objects.equals(before.getPerms(), after.getPerms())) {
            builder.append(String.format("perms[%s => %s] ", before.getPerms(), after.getPerms()));
        }
        return builder.toString();
    }
Create a new {@code ResourceChangedEvent}.operator is unknown.

@param source   Current rule state
@param before   Before the change rule state
@param type     event type
@param operator operator
shenyu-admin/src/main/java/org/apache/shenyu/admin/model/event/resource/ResourceChangedEvent.java