Struct ConditionalDispenser 

pub struct ConditionalDispenser { /* private fields */ }

Wraps an inner OpDispenser with a conditional check.

Evaluates a named field in ResolvedFields before executing. If the field is falsy (0, 0.0, false, empty string, None), the op is skipped — no inner execution, no adapter call. Returns OpResult::skipped().

The condition Polydat name is resolved at init time via ScopeFixture::register_pull and read at cycle time through the stored PullHandle against ExecCtx::pulls.

Implementations

impl ConditionalDispenser

pub fn wrap( inner: Arc<dyn OpDispenser>, condition_field: &str, metrics: Arc<ActivityMetrics>, fx: &mut ScopeFixture, ) -> Result<Arc<dyn OpDispenser>, String>

Wrap an inner dispenser with a condition check, registering condition_field into the supplied scope fixture so the per-cycle read goes through the canonical PullPlan path (SRD 32 §“Init-Time Fixture and Consumer Self-Registration”).

Errors if the kernel doesn’t know condition_field.

Trait Implementations

impl OpDispenser for ConditionalDispenser

fn execute<'a>( &'a self, cycle: u64, ctx: &'a ExecCtx<'a>, ) -> Pin<Box<dyn Future<Output = Result<OpResult, ExecutionError>> + Send + 'a>>

Execute an operation for the given cycle.

fn inner_dispenser(&self) -> Option<&dyn OpDispenser>

Returns the wrapped dispenser when this is a wrapper, None when this is a leaf (the adapter’s base dispenser — e.g. CQL raw / prepared / batch, HTTP, stdout, plotter, …).

fn describe(&self) -> Option<String>

One-line description of the op this dispenser represents — typically the statement text / request shape with bind-point placeholders left unresolved ({table}, {key}, ?, …).

fn describe_resolved(&self, wires: &dyn WireSource) -> Option<String>

Render the actual op the dispenser would fire for the given cycle — the dryrun-equivalent view of the statement after every bind point is interpolated.

fn canonical_kernel(&self) -> Option<&Arc<dyn Kernel>>

SRD-68 invariant I-3 — the dispenser’s canonical Polydat Kernel, established at construction by map_op from its parent — the parent itself, or a kernel bound under it. Any engine: the executor finds the program to bind per fiber by program_id. Returns None for dispensers that don’t own a kernel (adapters with no Polydat needs, or wrappers that delegate to an inner dispenser).

fn adapter_metrics(&self) -> Vec<(String, Labels, MetricValue)>

Snapshot adapter-specific metrics for inclusion in the capture snapshot.

fn status_counters(&self) -> Vec<(&str, u64)>

Adapter-specific status line entries (cumulative, non-destructive read).

fn rows_per_op(&self) -> usize

The op’s uniform per-invocation cursor consumption — how many consecutive wire ordinals one execute call reads and covers.

impl WrappingDispenser for ConditionalDispenser

Test whether a resolved field value is truthy.