/*
* Copyright © 2015 Cask Data, Inc.
*
* 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 co.cask.cdap.common.conf;
import co.cask.cdap.api.annotation.Plugin;
import co.cask.cdap.api.plugin.PluginClass;
import co.cask.cdap.api.plugin.PluginPropertyField;
import com.google.common.collect.ImmutableMap;
import com.google.common.reflect.TypeToken;
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 java.lang.reflect.Type;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
/**
* A Gson deserializater for creating {@link PluginClass} object from external plugin config file.
* Used to verify that required fields are present and property map is never null.
*/
public class PluginClassDeserializer implements JsonDeserializer<PluginClass> {
// Type for the PluginClass.properties map.
private static final Type PROPERTIES_TYPE = new TypeToken<Map<String, PluginPropertyField>>() { }.getType();
//Type for endpoints property
private static final Type ENDPOINTS_TYPE = new TypeToken<Set<String>>() { }.getType();
@Override
public PluginClass deserialize(JsonElement json, Type typeOfT,
JsonDeserializationContext context) throws JsonParseException {
if (!json.isJsonObject()) {
throw new JsonParseException("PluginClass should be a JSON Object");
}
JsonObject jsonObj = json.getAsJsonObject();
String type = jsonObj.has("type") ? jsonObj.get("type").getAsString() : Plugin.DEFAULT_TYPE;
String name = getRequired(jsonObj, "name").getAsString();
String description = jsonObj.has("description") ? jsonObj.get("description").getAsString() : "";
String className = getRequired(jsonObj, "className").getAsString();
Set<String> endpointsSet = new HashSet<>();
if (jsonObj.has("endpoints")) {
endpointsSet = context.deserialize(jsonObj.get("endpoints"), ENDPOINTS_TYPE);
}
Map<String, PluginPropertyField> properties = jsonObj.has("properties")
? context.<Map<String, PluginPropertyField>>deserialize(jsonObj.get("properties"), PROPERTIES_TYPE)
: ImmutableMap.<String, PluginPropertyField>of();
return new PluginClass(type, name, description, className, null, properties, endpointsSet);
}
private JsonElement getRequired(JsonObject jsonObj, String name) {
if (!jsonObj.has(name)) {
throw new JsonParseException("Property '" + name + "' is missing from PluginClass.");
}
return jsonObj.get(name);
}
}