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Diffstat (limited to 'src/main/scala/cc/spray/json/AdditionalFormats.scala')
-rw-r--r-- | src/main/scala/cc/spray/json/AdditionalFormats.scala | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/src/main/scala/cc/spray/json/AdditionalFormats.scala b/src/main/scala/cc/spray/json/AdditionalFormats.scala new file mode 100644 index 0000000..62a30e7 --- /dev/null +++ b/src/main/scala/cc/spray/json/AdditionalFormats.scala @@ -0,0 +1,62 @@ +/* + * Original implementation (C) 2009-2011 Debasish Ghosh + * Adapted and extended in 2011 by Mathias Doenitz + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package cc.spray.json + +/** + * Provides additional JsonFormats and helpers + */ +trait AdditionalFormats { + + implicit object JsValueFormat extends JsonFormat[JsValue] { + def write(value: JsValue) = value + def read(value: JsValue) = value + } + + def formatFromWriter[T :JsonWriter] = new JsonFormat[T] { + def write(obj: T) = obj.toJson + def read(value: JsValue) = throw new RuntimeException("JsonFormat constructed from JsonWriter can't read from JSON") + } + + def formatFromReader[T :JsonReader] = new JsonFormat[T] { + def write(obj: T) = throw new RuntimeException("JsonFormat constructed from JsonReader can't write JSON") + def read(value: JsValue) = value.fromJson[T] + } + + /** + * Lazy wrapper around serialization. Useful when you want to serialize (mutually) recursive structures. + */ + def lazyFormat[T](format: => JsonFormat[T]) = new JsonFormat[T]{ + lazy val delegate = format; + def write(x: T) = delegate.write(x); + def read(value: JsValue) = delegate.read(value); + } + + /** + * Wraps an existing JsonReader with Exception protection. + */ + def safeReader[A :JsonReader] = new JsonReader[Either[Exception, A]] { + def read(json: JsValue) = { + try { + Right(json.fromJson) + } catch { + case e: Exception => Left(e) + } + } + } + +}
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