/*
* Copyright 2012-2013 Hauser Olsson GmbH
*
* 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 ch.agent.crnickl.mongodb;
import org.bson.types.ObjectId;
import ch.agent.crnickl.T2DBException;
import ch.agent.crnickl.T2DBMsg;
import ch.agent.crnickl.T2DBMsg.E;
import ch.agent.crnickl.api.Property;
import ch.agent.crnickl.api.Surrogate;
import ch.agent.crnickl.impl.Permission;
import ch.agent.crnickl.impl.SchemaUpdatePolicy;
import com.mongodb.BasicDBObject;
import com.mongodb.DBCollection;
import com.mongodb.WriteConcern;
/**
* A stateless object with methods providing write access to properties.
* <p>
* A property in MongoDB is stored as:
* <blockquote><pre><code>
* { _id : OID,
* name : STRING,
* type : OID,
* indexed : BOOLEAN
* }
* </code></pre></blockquote>
* The <em>type</em> field identifies the value type.
* <p>
* @author Jean-Paul Vetterli
*/
public class WriteMethodsForProperty extends ReadMethodsForProperty {
public WriteMethodsForProperty() {
}
/**
* Create a new property and return its key.
* If creation fails throw an exception.
*
* @param prop a property
* @throws T2DBException
*/
public <T>void createProperty(Property<T> prop) throws T2DBException {
Surrogate surrogate = null;
Throwable cause = null;
try {
check(Permission.CREATE, prop);
BasicDBObject dob = pack(prop);
getMongoDB(prop).getProperties().insert(dob);
ObjectId ox = getObjectId(dob);
surrogate = makeSurrogate(prop, new MongoDBObjectId(ox));
} catch (Exception e) {
cause = e;
} finally {
}
if (surrogate == null || cause != null)
throw T2DBMsg.exception(cause, E.E20114, prop.getName());
prop.getSurrogate().upgrade(surrogate);
}
/**
* Delete the property.
* If deleting fails throw an exception.
*
* @param prop a property
* @param policy a schema updating policy
* @throws T2DBException
*/
public <T>void deleteProperty(Property<T> prop, SchemaUpdatePolicy policy) throws T2DBException {
boolean done = false;
Throwable cause = null;
Surrogate s = prop.getSurrogate();
MongoDatabase database = (MongoDatabase) s.getDatabase();
try {
check(Permission.MODIFY, prop);
// dangerous update! see comment in MongoDatabase.sleep
policy.willDelete(prop);
Property<T> original = database.getReadMethodsForProperty().getProperty(s);
DBCollection coll = getMongoDB(s).getProperties();
coll.remove(asQuery(s.getId()), WriteConcern.SAFE);
database.sleep();
try {
policy.willDelete(original);
} catch (T2DBException e) {
createProperty(original);
throw e;
}
done = true;
} catch (Exception e) {
cause = e;
} finally {
}
if (!done || cause != null)
throw T2DBMsg.exception(cause, E.E20115, prop.getName());
}
/**
* Update the name of the property.
* If updating fails throw an exception.
*
* @param prop a property
* @param policy a schema updating policy
* @throws T2DBException
*/
public void updateProperty(Property<?> prop, SchemaUpdatePolicy policy) throws T2DBException {
boolean done = false;
Throwable cause = null;
Surrogate s = prop.getSurrogate();
try {
check(Permission.MODIFY, prop);
DBCollection coll = getMongoDB(s).getProperties();
coll.update(asQuery(s.getId()), operation(Operator.SET, MongoDatabase.FLD_PROP_NAME, prop.getName()));
done = true;
} catch (Exception e) {
cause = e;
} finally {
}
if (!done || cause != null)
throw T2DBMsg.exception(cause, E.E20116, prop.getName());
}
/**
* Packs a property into a BSON object.
*
* @param prop a Property
* @return a BasicDBObject
*/
private <T>BasicDBObject pack(Property<T> prop) {
com.mongodb.BasicDBObject bo = new BasicDBObject();
if (!prop.getSurrogate().inConstruction())
bo.put(MongoDatabase.FLD_ID, getId(prop));
bo.put(MongoDatabase.FLD_PROP_NAME, prop.getName());
bo.put(MongoDatabase.FLD_PROP_VT, getId(prop.getValueType()));
bo.put(MongoDatabase.FLD_PROP_INDEXED, prop.isIndexed());
return bo;
}
}