public void serializeForUpdate(QueryMetadata md, Map<Path<?>, Expression<?>> updates) {
        append(UPDATE);
        handleJoinTarget(md.getJoins().get(0));
        append(SET);
        boolean first = true;
        for (Map.Entry<Path<?>, Expression<?>> entry : updates.entrySet()) {
            if (!first) {
                append(", ");
            }
            handle(entry.getKey());
            append(" = ");
            handle(entry.getValue());
            first = false;
        }
        if (md.getWhere() != null) {
            append(WHERE).handle(md.getWhere());
        }
    }
{@code JPQLSerializer} serializes Querydsl expressions into JPQL syntax.

@author tiwe
querydsl-jpa/src/main/java/com/querydsl/jpa/JPQLSerializer.java