webservices/server-integration/src/main/java/org/jboss/as/webservices/util/ASHelper.java
public static <A> A getRequiredAttachment(final DeploymentUnit unit, final AttachmentKey<A> key) {
        final A value = unit.getAttachment(key);
        if (value == null) {
            throw new IllegalStateException();
        }

        return value;
    }
public static <A> A getRequiredAttachment(final DeploymentUnit unit, final AttachmentKey<A> key) {
        final A value = unit.getAttachment(key);
        if (value == null) {
            throw new IllegalStateException();
        }

        return value;
    }
Returns required attachment value from deployment unit.

@param <A> expected value
@param unit deployment unit
@param key attachment key
@return required attachment
@throws IllegalStateException if attachment value is null