/*
* Copyright (C) 2011 Benoit GUEROUT <bguerout at gmail dot com> and Yves AMSELLEM <amsellem dot yves at gmail dot com>
*
* 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 org.jongo.spike.projection;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.jsonschema.JsonSchema;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.mongodb.BasicDBObject;
import com.mongodb.DBObject;
import org.jongo.query.Query;
import java.util.Iterator;
import java.util.Map;
public class JacksonProjection implements Projection {
private final ObjectMapper mapper;
public JacksonProjection(ObjectMapper mapper) {
this.mapper = mapper;
}
public Query getProjectionQuery(Class<?> pojoClass) {
DBObject query = new BasicDBObject();
putFieldNames(query, getSchemaNode(pojoClass));
query.removeField("_id");
return new ProjectionQuery(query);
}
private ObjectNode getSchemaNode(Class<?> pojoClass) {
try {
JsonSchema schema = mapper.generateJsonSchema(pojoClass);
return schema.getSchemaNode();
} catch (Exception e) {
throw new RuntimeException("Unable to create field DBObject for class: " + pojoClass, e);
}
}
private void putFieldNames(DBObject dbo, JsonNode node) {
JsonNode properties = node.get("properties");
Iterator<Map.Entry<String, JsonNode>> fields = properties.fields();
while (fields.hasNext()) {
Map.Entry<String, JsonNode> field = fields.next();
String fieldName = field.getKey();
JsonNode value = field.getValue();
if (value.has("properties")) {
BasicDBObject children = new BasicDBObject();
putFieldNames(children, value);
dbo.put(fieldName, children);
} else {
dbo.put(fieldName, 1);
}
}
}
private static class ProjectionQuery implements Query {
private final DBObject dbo;
private ProjectionQuery(DBObject dbo) {
this.dbo = dbo;
}
public DBObject toDBObject() {
return dbo;
}
}
}