Module com.darkcollective.relix.semantic

Package com.darkcollective.relix.semantic.internal

Class LogicalPlanJson

java.lang.Object

com.darkcollective.relix.semantic.internal.LogicalPlanJson

public final class LogicalPlanJson
extends Object

Serializes a logical relational-algebra tree to JSON, annotating every node with its inferred Schema.

This is the machine-readable counterpart to IrReport's ASCII expression trees: it walks the same RelNode structure (reusing IrReport.baseLabel(com.darkcollective.relix.ast.RelNode, com.darkcollective.relix.symbol.table.SymbolTable) and IrReport.nodeChildren(com.darkcollective.relix.ast.RelNode)) but emits a structured tree suitable for tooling — the playground's AST panel, and any consumer wanting schema-bearing output.

Node shape

Each node is a JSON object:

 {
   "op": "Selection",            // RelNode type, "Node" suffix stripped
   "label": "σ amount > 100",    // human-readable operator form (no [mat] tag)
   "schema": { "open": false,    // inferred output schema, or null if unknown
               "columns": [ { "name": "amount", "type": "N" }, … ] },
   "materialization": "stream",  // stream | bag | set | sort
   "children": [ … ]             // child node objects, left-to-right
 }
 

Leaf RelationNodes additionally carry "relation" (the relation name) and "kind" (its symbol kind code, e.g. "SRC", or "?" when unresolved).

Schema encoding

• null — no schema was inferred for the node (its subtree failed to resolve), or the inference placeholder is present.
• { "open": true, "columns": [] } — an open (schema-on-read) relation whose columns resolve dynamically at runtime.
• { "open": false, "columns": [ … ] } — a closed, fully-typed schema.

Column types use the same one-letter codes as IrReport: Number, String, Boolean, ?=any.

Method Summary

Modifier and Type	Method	Description
static String	toJson(RelNode root, SymbolTable table, SchemaAnnotations schemas)	Serializes the tree rooted at root to a standalone JSON string.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

toJson

public static String toJson(RelNode root,
 SymbolTable table,
 SchemaAnnotations schemas)

Serializes the tree rooted at root to a standalone JSON string.

Parameters:

root - the root RA node; must not be null

table - the symbol table, for leaf relation kinds; must not be null

schemas - the inferred schema annotations; must not be null

Returns:

the JSON document for the tree