spring-projects/spring-ai · error · UnsupportedOperationException

Not supported expression type:

Error message

Not supported expression type: 

What it means

S3VectorFilterSearchExpressionConverter.getOperationSymbol throws UnsupportedOperationException when a Filter.ExpressionType has no S3 Vectors operator mapping. Only AND, NOT, OR, EQ, NE, LT, LTE, GT, GTE, NIN, IN are supported; anything else (e.g. types added in newer Spring AI versions) falls through to the default branch.

Source

Thrown at vector-stores/spring-ai-s3-vector-store/src/main/java/org/springframework/ai/vectorstore/s3/S3VectorFilterSearchExpressionConverter.java:59

	public S3VectorFilterSearchExpressionConverter() {
		this.dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
		this.dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
	}

	private String getOperationSymbol(Filter.ExpressionType exp) {
		return switch (exp) {
			case AND -> "$and";
			case NOT -> "$not";
			case OR -> "$or";
			case EQ -> "$eq";
			case NE -> "$ne";
			case LT -> "$lt";
			case LTE -> "$lte";
			case GT -> "$gt";
			case GTE -> "$gte";
			case NIN -> "$nin";
			case IN -> "$in";
			default -> throw new UnsupportedOperationException("Not supported expression type: " + exp);
		};
	}

	@Override
	public Document convertExpression(Filter.Expression expression) {
		String operationType = getOperationSymbol(expression.type());
		switch (expression.type()) {
			case EQ:
			case NE:
			case GTE:
			case GT:
			case LTE:
			case LT:
				return Document.fromMap(Map.of(((Filter.Key) expression.left()).key(), Document
					.fromMap(Map.of(operationType, wrapValue(Objects.requireNonNull(expression.right()))))));

			case IN:
			case NIN:

View on GitHub (pinned to 98a7beda4f)

Solutions

1. Rewrite the filter using only supported operators: EQ, NE, LT, LTE, GT, GTE, IN, NIN, AND, OR, NOT.
2. Emulate unsupported semantics: replace ISNULL/ISNOTNULL with NE/EQ against null or a sentinel metadata field.
3. Check your Spring AI version and upgrade, since newer releases expand the supported operator set.
4. If the type is legitimately needed, implement a custom S3VectorFilterExpressionConverter and register it with the S3VectorStore builder.

Example fix

// before
new Filter.Expression(Filter.ExpressionType.ISNULL, new Filter.Key("notes"), null)
// after
new Filter.Expression(Filter.ExpressionType.EQ, new Filter.Key("notes"), new Filter.Value(null))

private static final Set<Filter.ExpressionType> SUPPORTED = Set.of(AND, NOT, OR, EQ, NE, LT, LTE, GT, GTE, NIN, IN);
if (!SUPPORTED.contains(expr.type())) throw new IllegalArgumentException("Unsupported for S3: " + expr.type());

try { store.similaritySearch(req); } catch (UnsupportedOperationException e) { log.warn("Filter uses unsupported operator: {}", e.getMessage()); }

When it happens

Trigger: Calling S3VectorStore similaritySearch with a SearchRequest filter expression whose Filter.ExpressionType is not in the switch (e.g. ISNULL/ISNOTNULL, or an enum constant from a newer Spring AI release), which reaches getOperationSymbol via convertExpression.

Common situations: Upgrading Spring AI and using new filter operators against the S3 vector store before converter support was added; hand-constructing Filter.Expression objects with exotic types; copying filters built for another store (e.g. PgVector) that supports more operators.

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

• Unsupported operator:
• Not supported expression type:
• Unsupported Number type:
• Unsupported operand type:
• Expression of type %s requires a left operand

AI-assisted analysis of spring-projects/spring-ai@98a7beda4f (2026-09-11). Data as JSON: /api/errors/e1985d9c9fa57445. Report an issue: GitHub.