wip

1 files changed, 31 insertions, 0 deletions

diff --git a/src/main/java/moe/nea/pcj/json/JsonCodec.java b/src/main/java/moe/nea/pcj/json/JsonCodec.java
new file mode 100644
index 0000000..65f4a5e
--- /dev/null
+++ b/src/main/java/moe/nea/pcj/json/JsonCodec.java
@@ -0,0 +1,31 @@
+package moe.nea.pcj.json;
+
+import moe.nea.pcj.Codec;
+import moe.nea.pcj.Result;
+
+public interface JsonCodec<T, Format> extends Codec<
+		T, Format, JsonLikeOperations<Format>,
+		JsonLikeError, JsonLikeError> {
+
+	default MapCodec<T, Format> fieldOf(String key) {
+		return new MapCodec<>() {
+			@Override
+			public Result<T, JsonLikeError> decode(RecordView<Format> record, JsonLikeOperations<Format> ops) {
+				return record.get(key)
+				             .map(element -> Result.<T, JsonLikeError>cast(
+						             JsonCodec.this.decode(element, ops)
+						                           .mapError(it -> new AtField(key, it))))
+				             .orElseGet(() -> Result.fail(new MissingKey(key)));
+			}
+
+			@Override
+			public Result<RecordBuilder<Format>, JsonLikeError> encode(T value, JsonLikeOperations<Format> ops) {
+				var record = ops.createObject();
+				return Result.<Format, JsonLikeError>cast(JsonCodec.this.encode(value, ops))
+				             .<JsonLikeError>mapError(it -> new AtField(key, it))
+				             .flatMap(json -> Result.cast(record.add(key, json).map(unit -> record)));
+			}
+
+		};
+	}
+}