10000 Added trait to encapsulate common functions used in record objects. · randomcoding/scala-utilities@f8d9d68 · GitHub
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Added trait to encapsulate common functions used in record objects.
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‎scala-utilities-lift/src/main/scala/uk/co/randomcoding/scala/util/lift/mongodb/BaseMongoRecordObject.scala

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/**
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* Copyright (C) 2012 - RandomCoder <randomcoder@randomcoding.co.uk>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* Contributors:
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* RandomCoder <randomcoder@randomcoding.co.uk> - initial API and implementation and/or initial documentation
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*/
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package uk.co.randomcoding.scala.util.lift.mongodb
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import org.bson.types.ObjectId
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import net.liftweb.mongodb.record.MongoMetaRecord
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import net.liftweb.mongodb.record.MongoRecord
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import net.liftweb.mongodb.record.field.ObjectIdPk
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import com.foursquare.rogue.Rogue
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/**
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* Provides common functionality for record companion objects to find matching records and find records by id.
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*
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* Requires that the type `T extend MongoRecord[T] with ObjectIdPk[T]`
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*
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* Users of this trait are required to implement the `findById(org.bson.types.ObjectId)` and
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* `matchingRecord(T)` methods.
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*
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* @author RandomCoder <randomcoder@randomcoding.co.uk>
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*
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* Created On: 29 Jul 2012
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*/
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trait BaseMongoRecordObject[T <: MongoRecord[T] with ObjectIdPk[T]] {
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/**
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* Find a record by its object id - typically its `id` or `_id` field.
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*
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* Should return `Some(record)` if there is a record of ths type with the given object id or `None` if there is not.
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*/
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def findById(oid: ObjectId): Option[T]
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/**
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* Find a record that matched the input one, if one is present in the database.
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*
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* The definition of a match is left up to the implementer, but it is often good to be
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* consistent with the companion classes `equals` method.
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*
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* This method is only required to return a single match, even if there are multiple matches in the database,
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* so the exact match strategy and precedence is left up to the implementor.
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*
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* As this is primarily used (by me) to check that there are no matching records present, then this is sufficient.
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*
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* @return An optional record if there is a match found, or `None` if there are no records that match.
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*/
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def matchingRecord(t: T): Option[T]
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/**
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* Updates the record with the given `ObjectId` with the values from the new record.
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*
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* If there is no record with the given `ObjectId` then this method '''should not''' add the
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* new record, it should return `None`.
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*
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* If there is a record with the given `ObjectId` then that record should have all its values set to the
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* ones in the new record. The updated record should be returned inside an Option.
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*/
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final def update(oid: ObjectId, newT: T): Option[T] = findById(oid) match {
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case Some(record) => newT.id(oid).saveTheRecord
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case _ => None
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}
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/**
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* Remove the record with the given `ObjectId` from the collection of this type.
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*
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* @return The removed record, or if there is no record with the given `ObjectId`,
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* or if the remove operation fails `None`
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*/
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final def remove(oid: ObjectId): Option[T] = findById(oid) match {
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case Some(record) => if (record.delete_!) Some(record) else None
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case _ => None
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}
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/**
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* Finds a ''matching'' record in the database.
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*
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* A ''match'' is made if:
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*
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* - There is another record with the same Object Id
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* - A record is returned from the [[uk.co.randomcoding.scala.util.lift.mongodb.BaseMongoRecordObject#matchingRecord(T)]]
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*
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* @return The optional match, or `None` if there is no match
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*/
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final def findMatching(t: T): Option[T] = findById(t.id.get) match {
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case Some(r) => Some(r)
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case _ => matchingRecord(t)
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}
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/**
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* Add a new record to the database unless there is a matching record.
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*
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* If there is a matching record then '''do not''' add the new one.
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*
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* A match is determined by calling the `findMatching(T)` method,
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* with a return value of Some(t) indicating there is a matching record.
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*
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* @return The optionally added record, or if there is a match then the matched record.
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*/
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final def add(t: T): Option[T] = findMatching(t) match {
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case Some(t) => Some(t)
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case _ => t.saveTheRecord
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}
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}

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