spring-projects/spring-ai · error · UnsupportedOperationException

Not supported expression type:

Error message

Not supported expression type:

What it means

getOperationSymbol's default branch throws UnsupportedOperationException for any Filter.ExpressionType not explicitly mapped to a Weaviate GraphQL where-filter operator (EQ, NE, LT, LTE, GT, GTE; IN/NIN are handled separately). It means the expression contains an operator Weaviate's filter syntax cannot express.

Solutions

  1. Rewrite the filter using supported operators: EQ, NE, LT, LTE, GT, GTE, and IN/NIN (auto-expanded).
  2. Upgrade spring-ai-weaviate-store in case support for the operator was added in a newer version.
  3. Pre-check expression types per store and route unsupported filters to a store that supports them or fail fast with a clear message.

Example fix

// before
var expr = new Filter.Expression(Filter.ExpressionType.CONTAINS, new Key("text"), new Value("ai"));
// after
var expr = new Filter.Expression(Filter.ExpressionType.EQ, new Key("text"), new Value("ai"));
Defensive patterns

Strategy: validation

Validate before calling

Set<Filter.ExpressionType> WEAVIATE_SUPPORTED = Set.of(EQ, NE, LT, LTE, GT, GTE, IN, NIN); if (!WEAVIATE_SUPPORTED.contains(expr.type())) throw new IllegalArgumentException("Weaviate cannot filter on " + expr.type());

Try / catch

try { vectorStore.similaritySearch(req); } catch (UnsupportedOperationException e) { if (e.getMessage().startsWith("Not supported expression type")) { /* rewrite filter with supported operators */ } else throw e; }

Prevention

When it happens

Trigger: Passing a Filter.Expression with an unmapped type (any operator outside the switch cases) through WeaviateVectorStore similaritySearch or directly into WeaviateFilterExpressionConverter.

Common situations: Newer Spring AI Filter.ExpressionType values appearing after a library upgrade without a matching converter update; generic filter code shared across stores passing operators only some stores support.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of spring-projects/spring-ai@98a7beda4f (2026-09-11). Data as JSON: /api/errors/6b5bf44f836be287. Report an issue: GitHub.

Appendix: source

Thrown at vector-stores/spring-ai-weaviate-store/src/main/java/org/springframework/ai/vectorstore/weaviate/WeaviateFilterExpressionConverter.java:122

			this.convertOperand(exp.right(), context);
		}
	}

	private String getOperationSymbol(Expression exp) {
		return switch (exp.type()) {
			case AND -> "operator:And \n";
			case OR -> "operator:Or \n";
			case EQ -> "operator:Equal \n";
			case NE -> "operator:NotEqual \n";
			case LT -> "operator:LessThan \n";
			case LTE -> "operator:LessThanEqual \n";
			case GT -> "operator:GreaterThan \n";
			case GTE -> "operator:GreaterThanEqual \n";
			case IN -> throw new IllegalStateException(
					"The 'IN' operator should have been transformed into chain of OR/EQ expressions.");
			case NIN -> throw new IllegalStateException(
					"The 'NIN' operator should have been transformed into chain of AND/NEQ expressions.");
			default -> throw new UnsupportedOperationException("Not supported expression type:" + exp.type());
		};
	}

	@Override
	protected void doKey(Key key, StringBuilder context) {
		var identifier = (hasOuterQuotes(key.key())) ? removeOuterQuotes(key.key()) : key.key();
		context.append("path:[");
		emitJsonValue(withMetaPrefix(identifier), context);
		context.append("] \n");
	}

	public String withMetaPrefix(String identifier) {
		if (SYSTEM_IDENTIFIERS.contains(identifier)) {
			return identifier;
		}

		if (this.allowedIdentifierNames.contains(identifier)) {
			return this.metaFieldPrefix + identifier;

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