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/*
* 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
}
class DelegatingFormat[T](delegate: JsonFormat[T]) extends JsonFormat[T] {
def write(obj: T) = delegate.write(obj)
def read(json: JsValue) = delegate.read(json)
}
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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