public static <ENTITY> long countHelper(
        final SqlStreamOptimizerInfo<ENTITY> info,
        final SqlStreamTerminator<ENTITY> sqlStreamTerminator,
        final Pipeline pipeline,
        final LongSupplier fallbackSupplier
    ) {
        requireNonNull(info);
        requireNonNull(sqlStreamTerminator);
        requireNonNull(pipeline);
        requireNonNull(fallbackSupplier);

        // Can we count it directly (with no sub-select query)?
        if (pipeline.stream().allMatch(PRESERVE_SIZE)) {
            return info.getCounter().applyAsLong(info.getSqlSelectCount(), emptyList());
        } else {

            final Pipeline optimizedPipeline = sqlStreamTerminator.optimize(pipeline);
            // Can we count using a sub-select query?
            if (optimizedPipeline.stream().allMatch(PRESERVE_SIZE)) {
                final AsynchronousQueryResult<ENTITY> asynchronousQueryResult = sqlStreamTerminator.getAsynchronousQueryResult();
                final StringBuilder sql = new StringBuilder()
                    .append("SELECT COUNT(*) FROM (")
                    .append(asynchronousQueryResult.getSql())
                    .append(")");

                if (info.getDbmsType().getSubSelectAlias() == SubSelectAlias.REQUIRED) {
                    sql.append(" AS A");
                }
                @SuppressWarnings("unchecked")
                final List<Object> values = (List<Object>) asynchronousQueryResult.getValues();
                return info.getCounter().applyAsLong(sqlStreamTerminator.attachTraceData(sql.toString()), values);
            } else {
                // Iterate over all materialized ENTITIES....
                return fallbackSupplier.getAsLong();
            }
        }
    }
Optimizer for count operations.

@param <ENTITY> the entity type
@param info about the stream optimizer
@param sqlStreamTerminator that called us
@param pipeline the pipeline
@param fallbackSupplier a fallback supplier should every item be size
retaining
@return the number of rows
runtime-parent/runtime-core/src/main/java/com/speedment/runtime/core/internal/component/sql/override/optimized/util/CountUtil.java