/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 com.google.wave.api.impl;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;
import com.google.wave.api.OperationRequest;
import com.google.wave.api.JsonRpcConstant.ParamsProperty;
import com.google.wave.api.JsonRpcConstant.RequestProperty;
import com.google.wave.api.OperationRequest.Parameter;
import java.lang.reflect.Type;
import java.util.Map.Entry;
/**
* Custom serializer and deserializer that serializes and deserializes an
* {@link OperationRequest}.
*
* @author mprasetya@google.com (Marcel Prasetya)
*/
public class OperationRequestGsonAdaptor implements JsonSerializer<OperationRequest>,
JsonDeserializer<OperationRequest> {
/**
* A namespace that should be prepended to the operation method during
* serialization.
*/
private final String operationNamespace;
/**
* Constructor.
*/
public OperationRequestGsonAdaptor() {
this("");
}
/**
* Constructor.
*
* @param operationNamespace namespace that should be prepended to the
* operation method during serialization.
*/
public OperationRequestGsonAdaptor(String operationNamespace) {
if (operationNamespace != null && !operationNamespace.isEmpty() &&
!operationNamespace.endsWith(".")) {
operationNamespace += ".";
}
this.operationNamespace = operationNamespace;
}
@Override
public JsonElement serialize(OperationRequest req, Type type, JsonSerializationContext ctx) {
JsonObject object = new JsonObject();
object.addProperty(RequestProperty.METHOD.key(), operationNamespace + req.getMethod());
object.addProperty(RequestProperty.ID.key(), req.getId());
JsonObject parameters = new JsonObject();
for (Entry<ParamsProperty, Object> entry : req.getParams().entrySet()) {
if (entry.getValue() != null) {
parameters.add(entry.getKey().key(), ctx.serialize(entry.getValue()));
}
}
object.add(RequestProperty.PARAMS.key(), parameters);
return object;
}
@Override
public OperationRequest deserialize(JsonElement json, Type type, JsonDeserializationContext ctx)
throws JsonParseException {
JsonObject jsonObject = json.getAsJsonObject();
JsonObject parameters = jsonObject.getAsJsonObject(RequestProperty.PARAMS.key());
OperationRequest request = new OperationRequest(
jsonObject.get(RequestProperty.METHOD.key()).getAsString(),
jsonObject.get(RequestProperty.ID.key()).getAsString(),
getPropertyAsStringThenRemove(parameters, ParamsProperty.WAVE_ID),
getPropertyAsStringThenRemove(parameters, ParamsProperty.WAVELET_ID),
getPropertyAsStringThenRemove(parameters, ParamsProperty.BLIP_ID));
for (Entry<String, JsonElement> parameter : parameters.entrySet()) {
ParamsProperty parameterType = ParamsProperty.fromKey(parameter.getKey());
if (parameterType != null) {
Object object;
if (parameterType == ParamsProperty.RAW_DELTAS) {
object = ctx.deserialize(parameter.getValue(), GsonFactory.RAW_DELTAS_TYPE);
} else {
object = ctx.deserialize(parameter.getValue(), parameterType.clazz());
}
request.addParameter(Parameter.of(parameterType, object));
}
}
return request;
}
/**
* Returns a property of {@code JsonObject} as a {@link String}, then remove
* that property.
*
* @param jsonObject the {@code JsonObject} to get the property from.
* @param key the key of the property.
* @return the property as {@link String}, or {@code null} if not found.
*/
private static String getPropertyAsStringThenRemove(JsonObject jsonObject, ParamsProperty key) {
JsonElement property = jsonObject.get(key.key());
if (property != null) {
jsonObject.remove(key.key());
if (property.isJsonNull()) {
return null;
}
return property.getAsString();
}
return null;
}
}