AbstractJackson2Decoder#decodeToMono support non-blocking parsing

spring-web/src/main/java/org/springframework/http/codec/cbor/Jackson2CborDecoder.java

@@ -23,9 +23,13 @@
 import org.jspecify.annotations.Nullable;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.util.context.ContextView;
 
 import org.springframework.core.ResolvableType;
+import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.http.MediaType;
 import org.springframework.http.codec.json.AbstractJackson2Decoder;
 import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
@@ -58,4 +62,15 @@ public Flux<Object> decode(Publisher<DataBuffer> input, ResolvableType elementTy
 		throw new UnsupportedOperationException("Does not support stream decoding yet");
 	}
 
+	@Override
+	public Mono<Object> decodeToMono(Publisher<DataBuffer> input, ResolvableType elementType, @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
+		return Mono.deferContextual(contextView -> {
+
+			Map<String, Object> hintsToUse = contextView.isEmpty() ? hints :
+					Hints.merge(hints, ContextView.class.getName(), contextView);
+
+			return DataBufferUtils.join(input, this.getMaxInMemorySize()).flatMap(dataBuffer ->
+					Mono.justOrEmpty(decode(dataBuffer, elementType, mimeType, hintsToUse)));
+		});
+	}
 }

spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Decoder.java

@@ -128,6 +128,10 @@ public boolean canDecode(ResolvableType elementType, @Nullable MimeType mimeType
 	public Flux<Object> decode(Publisher<DataBuffer> input, ResolvableType elementType,
 			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
 
+		return decodeToFlux(input, elementType, mimeType, hints, null);
+	}
+
+	private Flux<Object> decodeToFlux(Publisher<DataBuffer> input, ResolvableType elementType, @Nullable MimeType mimeType, @Nullable Map<String, Object> hints,@Nullable Boolean tokenizeArrays) {
 		ObjectMapper mapper = selectObjectMapper(elementType, mimeType);
 		if (mapper == null) {
 			return Flux.error(new IllegalStateException("No ObjectMapper for " + elementType));
@@ -138,8 +142,10 @@ public Flux<Object> decode(Publisher<DataBuffer> input, ResolvableType elementTy
 			forceUseOfBigDecimal = true;
 		}
 
-		boolean tokenizeArrays = (!elementType.isArray() &&
-				!Collection.class.isAssignableFrom(elementType.resolve(Object.class)));
+		if (tokenizeArrays == null) {
+			tokenizeArrays = (!elementType.isArray() &&
+					!Collection.class.isAssignableFrom(elementType.resolve(Object.class)));
+		}
 
 		Flux<DataBuffer> processed = processInput(input, elementType, mimeType, hints);
 		Flux<TokenBuffer> tokens = Jackson2Tokenizer.tokenize(processed, mapper.getFactory(), mapper,
@@ -188,15 +194,7 @@ protected Flux<DataBuffer> processInput(Publisher<DataBuffer> input, ResolvableT
 	@Override
 	public Mono<Object> decodeToMono(Publisher<DataBuffer> input, ResolvableType elementType,
 			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
-
-		return Mono.deferContextual(contextView -> {
-
-			Map<String, Object> hintsToUse = contextView.isEmpty() ? hints :
-					Hints.merge(hints, ContextView.class.getName(), contextView);
-
-			return DataBufferUtils.join(input, this.maxInMemorySize).flatMap(dataBuffer ->
-					Mono.justOrEmpty(decode(dataBuffer, elementType, mimeType, hintsToUse)));
-		});
+		return decodeToFlux(input, elementType, mimeType, hints, false).singleOrEmpty();
 	}
 
 	@Override

spring-web/src/main/java/org/springframework/http/codec/json/Jackson2Tokenizer.java

@@ -206,6 +206,9 @@ private boolean isTopLevelArrayToken(JsonToken token) {
 
 	private void assertInMemorySize(int currentBufferSize, List<TokenBuffer> result) {
 		if (this.maxInMemorySize >= 0) {
+			if (currentBufferSize > this.maxInMemorySize) {
+				raiseLimitException();
+			}
 			if (!result.isEmpty()) {
 				this.byteCount = 0;
 			}