Java tutorial
/******************************************************************************* * Copyright 2013 Open mHealth * * 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.openmhealth.reference.data.mongodb; import java.util.Collections; import java.util.LinkedList; import java.util.List; import org.mongojack.DBCursor; import org.mongojack.DBQuery; import org.mongojack.DBQuery.Query; import org.mongojack.JacksonDBCollection; import org.mongojack.internal.MongoJackModule; import org.openmhealth.reference.concordia.OmhValidationController; import org.openmhealth.reference.data.Registry; import org.openmhealth.reference.domain.MultiValueResult; import org.openmhealth.reference.domain.Schema; import org.openmhealth.reference.domain.mongodb.MongoMultiValueResultCursor; import org.openmhealth.reference.domain.mongodb.MongoMultiValueResultList; import org.openmhealth.reference.domain.mongodb.MongoSchema; import com.fasterxml.jackson.databind.InjectableValues; import com.fasterxml.jackson.databind.ObjectMapper; import com.mongodb.BasicDBObject; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.DBObject; import com.mongodb.QueryBuilder; /** * <p> * The interface to the database-backed Registry. * </p> * * @author John Jenkins */ public class MongoRegistry extends Registry { /** * The object mapper that should be used to parse {@link Schema}s. */ private static final ObjectMapper JSON_MAPPER; static { // Create the object mapper. ObjectMapper mapper = new ObjectMapper(); // Add our custom validation controller as an injectable parameter to // the Schema's constructor. InjectableValues.Std injectableValues = new InjectableValues.Std(); injectableValues.addValue(Schema.JSON_KEY_VALIDATION_CONTROLLER, OmhValidationController.VALIDATION_CONTROLLER); mapper.setInjectableValues(injectableValues); // Finally, we must configure the mapper to work with the MongoJack // configuration. JSON_MAPPER = MongoJackModule.configure(mapper); } /** * Default constructor. */ protected MongoRegistry() { // Get the collection to add indexes to. DBCollection collection = MongoDao.getInstance().getDb().getCollection(DB_NAME); // Ensure that there is an index on the ID. collection.ensureIndex(new BasicDBObject(Schema.JSON_KEY_ID, 1), DB_NAME + "_" + Schema.JSON_KEY_ID + "_index", false); // Ensure that there is an index on the version. collection.ensureIndex(new BasicDBObject(Schema.JSON_KEY_VERSION, 1), DB_NAME + "_" + Schema.JSON_KEY_VERSION + "_index", false); // Ensure that there is a compound, unique key on the ID and version. collection.ensureIndex((new BasicDBObject(Schema.JSON_KEY_ID, 1)).append(Schema.JSON_KEY_VERSION, 1), DB_NAME + "_" + Schema.JSON_KEY_ID + "_" + Schema.JSON_KEY_VERSION + "_unique", true); } /* * (non-Javadoc) * @see org.openmhealth.reference.data.Registry#getSchemaIds() */ public MultiValueResult<String> getSchemaIds(final long numToSkip, final long numToReturn) { // Get the connection to the database. DB db = MongoDao.getInstance().getDb(); // Get the connection to the registry with the Jackson wrapper. JacksonDBCollection<MongoSchema, Object> collection = JacksonDBCollection.wrap(db.getCollection(DB_NAME), MongoSchema.class); // Get the list of results. @SuppressWarnings("unchecked") List<String> results = collection.distinct(Schema.JSON_KEY_ID); // Remember the total number of results. int numResults = results.size(); // Sort the results. Collections.sort(results); // Get the lower index. int lowerIndex = (new Long(Math.min(numToSkip, results.size()))).intValue(); // Get the upper index. int upperIndex = (new Long(Math.min(numToSkip + numToReturn, results.size()))).intValue(); // Get the results based on the upper and lower bounds. results = results.subList(lowerIndex, upperIndex); // Create a MultiValueResult. MultiValueResult<String> result = new MongoMultiValueResultList<String>(results, numResults); // Return the list. return result; } /* * (non-Javadoc) * @see org.openmhealth.reference.data.Registry#getSchemaVersions(java.lang.String) */ public MultiValueResult<Long> getSchemaVersions(final String schemaId, final long numToSkip, final long numToReturn) { // Get the connection to the database. DB db = MongoDao.getInstance().getDb(); // Get the connection to the registry with the Jackson wrapper. JacksonDBCollection<MongoSchema, Object> collection = JacksonDBCollection.wrap(db.getCollection(DB_NAME), MongoSchema.class); // Get the list of results. @SuppressWarnings("unchecked") List<Long> results = collection.distinct(Schema.JSON_KEY_VERSION, new BasicDBObject(Schema.JSON_KEY_ID, schemaId)); // Remember the total number of results. int numResults = results.size(); // Sort the results. Collections.sort(results); // Get the lower index. int lowerIndex = (new Long(Math.min(numToSkip, results.size()))).intValue(); // Get the upper index. int upperIndex = (new Long(Math.min(numToSkip + numToReturn, results.size()))).intValue(); // Get the results based on the upper and lower bounds. results = results.subList(lowerIndex, upperIndex); // Create a MultiValueResult. MultiValueResult<Long> result = new MongoMultiValueResultList<Long>(results, numResults); // Return the list. return result; } /* * (non-Javadoc) * @see org.openmhealth.reference.data.Registry#getSchema(java.lang.String, long) */ public Schema getSchema(final String schemaId, final long schemaVersion) { // Get the connection to the database. DB db = MongoDao.getInstance().getDb(); // Get the connection to the registry with the Jackson wrapper. JacksonDBCollection<MongoSchema, Object> collection = JacksonDBCollection.wrap(db.getCollection(DB_NAME), MongoSchema.class, Object.class, JSON_MAPPER); // Build the query QueryBuilder queryBuilder = QueryBuilder.start(); // Add the schema ID. queryBuilder.and(MongoSchema.JSON_KEY_ID).is(schemaId); // Add the schema version. queryBuilder.and(MongoSchema.JSON_KEY_VERSION).is(schemaVersion); // Execute query. DBCursor<MongoSchema> result = collection.find(queryBuilder.get()); // Return null or the schema based on what the query returned. if (result.count() == 0) { return null; } else { return result.next(); } } /* * (non-Javadoc) * @see org.openmhealth.reference.data.Registry#getSchemas(java.lang.String, java.lang.Long, long, long) */ @Override public MultiValueResult<? extends Schema> getSchemas(final String schemaId, final Long schemaVersion, final long numToSkip, final long numToReturn) { // Get the connection to the database. DB db = MongoDao.getInstance().getDb(); // Get the connection to the registry with the Jackson wrapper. JacksonDBCollection<MongoSchema, Object> collection = JacksonDBCollection.wrap(db.getCollection(DB_NAME), MongoSchema.class, Object.class, JSON_MAPPER); // Create the fields to limit the query. List<Query> queries = new LinkedList<Query>(); // Add the schema ID, if given. if (schemaId != null) { queries.add(DBQuery.is(MongoSchema.JSON_KEY_ID, schemaId)); } // Add the schema version, if given. if (schemaVersion != null) { queries.add(DBQuery.is(MongoSchema.JSON_KEY_VERSION, schemaVersion)); } // Build the query based on the number of parameters. DBCursor<MongoSchema> result; if (queries.size() == 0) { result = collection.find(); } else { result = collection.find(DBQuery.and(queries.toArray(new Query[0]))); } // Build the sort field. DBObject sort = new BasicDBObject(); sort.put(MongoSchema.JSON_KEY_ID, -1); sort.put(MongoSchema.JSON_KEY_VERSION, -1); return new MongoMultiValueResultCursor<MongoSchema>( result.sort(sort).skip((new Long(numToSkip)).intValue()).limit((new Long(numToReturn)).intValue())); } }