org.apache.metamodel.mongodb.mongo3

Class MongoDbDataContext

java.lang.Object

org.apache.metamodel.AbstractDataContext

org.apache.metamodel.QueryPostprocessDataContext

org.apache.metamodel.mongodb.mongo3.MongoDbDataContext

All Implemented Interfaces:

HasReadTypeConverters, DataContext, UpdateableDataContext

public class MongoDbDataContext
extends QueryPostprocessDataContext
implements UpdateableDataContext

DataContext implementation for MongoDB. Since MongoDB has no schema, a virtual schema will be used in this DataContext. This implementation supports either automatic discovery of a schema or manual specification of a schema, through the SimpleTableDef class.

Field Summary

Fields inherited from class org.apache.metamodel.QueryPostprocessDataContext

INFORMATION_SCHEMA_NAME, SYSTEM_PROPERTY_CREATE_DEFAULT_TABLE_ALIAS

Constructor Summary

Constructors

Constructor and Description
MongoDbDataContext(com.mongodb.client.MongoDatabase mongoDb) Constructs a MongoDbDataContext and automatically detects the schema structure/view on all collections (see detectSchema(MongoDatabase)).
MongoDbDataContext(com.mongodb.client.MongoDatabase mongoDb, SimpleTableDef... tableDefs) Constructs a MongoDbDataContext.

Method Summary

Modifier and Type	Method and Description
protected void	addTable(MutableTable table)
protected org.bson.Document	createMongoDbQuery(Table table, List<FilterItem> whereItems, Consumer<FilterItem> whereItemToPostProcessConsumer)
static SimpleTableDef[]	detectSchema(com.mongodb.client.MongoDatabase mongoDb) Performs an analysis of the available collections in a Mongo DB instance and tries to detect the table's structure based on the first 1000 documents in each collection.
static SimpleTableDef	detectTable(com.mongodb.client.MongoDatabase mongoDb, String collectionName) Performs an analysis of an available collection in a Mongo DB instance and tries to detect the table structure based on the first 1000 documents in the collection.
protected Number	executeCountQuery(Table table, List<FilterItem> whereItems, boolean functionApproximationAllowed) Executes a simple count query, if possible.
protected Row	executePrimaryKeyLookupQuery(Table table, List<SelectItem> selectItems, Column primaryKeyColumn, Object keyValue) Executes a query which obtains a row by primary key (as defined by Column.isPrimaryKey()).
DataSet	executeQuery(Query query) Executes a query against the DataContext.
UpdateSummary	executeUpdate(UpdateScript update) Submits an UpdateScript for execution on the DataContext.
UpdateSummary	executeUpdate(UpdateScript update, com.mongodb.WriteConcern writeConcern) Executes an update with a specific WriteConcern.
UpdateSummary	executeUpdate(UpdateScript update, WriteConcernAdvisor writeConcernAdvisor) Executes an update with a specific WriteConcernAdvisor.
protected Schema	getMainSchema()
protected String	getMainSchemaName()
com.mongodb.client.MongoDatabase	getMongoDb() Gets the DB instance that this DataContext is backed by.
WriteConcernAdvisor	getWriteConcernAdvisor() Gets the WriteConcernAdvisor to use on executeUpdate(UpdateScript) calls.
protected DataSet	materializeMainSchemaTable(Table table, List<Column> columns, int maxRows) Executes a simple one-table query against a table in the main schema of the subclasses of this class.
protected DataSet	materializeMainSchemaTable(Table table, List<Column> columns, int firstRow, int maxRows) Executes a simple one-table query against a table in the main schema of the subclasses of this class.
void	setWriteConcernAdvisor(WriteConcernAdvisor writeConcernAdvisor) Sets a global WriteConcern advisor to use on executeUpdate(UpdateScript).

Methods inherited from class org.apache.metamodel.QueryPostprocessDataContext

addConverter, getDefaultSchemaName, getSchemaByNameInternal, getSchemaNamesInternal, isMainSchemaTable, isScalarFunctionMaterialized, materializeFromItem, materializeMainSchemaTable, materializeMainSchemaTableSelect, materializeTable

Methods inherited from class org.apache.metamodel.AbstractDataContext

compileQuery, executeQuery, executeQuery, getColumnByQualifiedLabel, getDefaultSchema, getSchemaByName, getSchemaNames, getSchemas, getTableByQualifiedLabel, isQualifiedPathDelim, onSchemaCacheRefreshed, parseQuery, query, refreshSchemas

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.metamodel.DataContext

compileQuery, executeQuery, executeQuery, getColumnByQualifiedLabel, getDefaultSchema, getSchemaByName, getSchemaNames, getSchemas, getTableByQualifiedLabel, parseQuery, query, refreshSchemas

Constructor Detail

MongoDbDataContext

public MongoDbDataContext(com.mongodb.client.MongoDatabase mongoDb,
                          SimpleTableDef... tableDefs)

Constructs a MongoDbDataContext. This constructor accepts a custom array of SimpleTableDefs which allows the user to define his own view on the collections in the database.

Parameters:

mongoDb - the mongo db connection

tableDefs - an array of SimpleTableDefs, which define the table and column model of the mongo db collections. (consider using detectSchema(MongoDatabase) or detectTable(MongoDatabase, String) ).

MongoDbDataContext

public MongoDbDataContext(com.mongodb.client.MongoDatabase mongoDb)

Constructs a MongoDbDataContext and automatically detects the schema structure/view on all collections (see detectSchema(MongoDatabase)).

Parameters:

mongoDb - the mongo db connection

Method Detail

detectSchema

public static SimpleTableDef[] detectSchema(com.mongodb.client.MongoDatabase mongoDb)

Performs an analysis of the available collections in a Mongo DB instance and tries to detect the table's structure based on the first 1000 documents in each collection.

Parameters:

mongoDb - the mongo db to inspect

Returns:

a mutable schema instance, useful for further fine tuning by the user.

See Also:

detectTable(MongoDatabase, String)

detectTable

public static SimpleTableDef detectTable(com.mongodb.client.MongoDatabase mongoDb,
                                         String collectionName)

Performs an analysis of an available collection in a Mongo DB instance and tries to detect the table structure based on the first 1000 documents in the collection.

Parameters:

mongoDb - the mongo DB

collectionName - the name of the collection

Returns:

a table definition for mongo db.

getMainSchema

protected Schema getMainSchema()
                        throws MetaModelException

Specified by:

getMainSchema in class QueryPostprocessDataContext

Returns:

the main schema that subclasses of this class produce

Throws:

MetaModelException

getMainSchemaName

protected String getMainSchemaName()
                            throws MetaModelException

Specified by:

getMainSchemaName in class QueryPostprocessDataContext

Returns:

the name of the main schema that subclasses of this class produce

Throws:

MetaModelException

executeCountQuery

protected Number executeCountQuery(Table table,
                                   List<FilterItem> whereItems,
                                   boolean functionApproximationAllowed)

Description copied from class: QueryPostprocessDataContext

Executes a simple count query, if possible. This method is provided to allow subclasses to optimize count queries since they are quite common and often a datastore can retrieve the count using some specialized means which is much more performant than counting all records manually.

Overrides:

executeCountQuery in class QueryPostprocessDataContext

Parameters:

table - the table on which the count is requested.

whereItems - a (sometimes empty) list of WHERE items.

functionApproximationAllowed - whether approximation is allowed or not.

Returns:

the count of the particular table, or null if not available.

executePrimaryKeyLookupQuery

protected Row executePrimaryKeyLookupQuery(Table table,
                                           List<SelectItem> selectItems,
                                           Column primaryKeyColumn,
                                           Object keyValue)

Description copied from class: QueryPostprocessDataContext

Executes a query which obtains a row by primary key (as defined by Column.isPrimaryKey()). This method is provided to allow subclasses to optimize lookup queries since they are quite common and often a datastore can retrieve the row using some specialized means which is much more performant than scanning all records manually.

Overrides:

executePrimaryKeyLookupQuery in class QueryPostprocessDataContext

Parameters:

table - the table on which the lookup is requested.

selectItems - the items to select from the lookup query.

primaryKeyColumn - the column that is the primary key

keyValue - the primary key value that is specified in the lookup query.

Returns:

the row if the particular table, or null if not available.

executeQuery

public DataSet executeQuery(Query query)

Description copied from interface: DataContext

Executes a query against the DataContext.

Specified by:

executeQuery in interface DataContext

Overrides:

executeQuery in class QueryPostprocessDataContext

Parameters:

query - the query object to execute

Returns:

the DataSet produced from executing the query

createMongoDbQuery

protected org.bson.Document createMongoDbQuery(Table table,
                                               List<FilterItem> whereItems,
                                               Consumer<FilterItem> whereItemToPostProcessConsumer)

materializeMainSchemaTable

protected DataSet materializeMainSchemaTable(Table table,
                                             List<Column> columns,
                                             int maxRows)

Description copied from class: QueryPostprocessDataContext

Executes a simple one-table query against a table in the main schema of the subclasses of this class.

Specified by:

materializeMainSchemaTable in class QueryPostprocessDataContext

Parameters:

table - the table to query

columns - the columns of the table to query

maxRows - the maximum amount of rows needed or -1 if all rows are wanted.

Returns:

a dataset with the raw table/column content.

materializeMainSchemaTable

protected DataSet materializeMainSchemaTable(Table table,
                                             List<Column> columns,
                                             int firstRow,
                                             int maxRows)

Description copied from class: QueryPostprocessDataContext

Executes a simple one-table query against a table in the main schema of the subclasses of this class. This default implementation will delegate to QueryPostprocessDataContext.materializeMainSchemaTable(Table, List, int) and apply a FirstRowDataSet if necessary.

Overrides:

materializeMainSchemaTable in class QueryPostprocessDataContext

Returns:

executeUpdate

public UpdateSummary executeUpdate(UpdateScript update,
                                   WriteConcernAdvisor writeConcernAdvisor)

Executes an update with a specific WriteConcernAdvisor.

executeUpdate

public UpdateSummary executeUpdate(UpdateScript update,
                                   com.mongodb.WriteConcern writeConcern)

Executes an update with a specific WriteConcern.

executeUpdate

public UpdateSummary executeUpdate(UpdateScript update)

Description copied from interface: UpdateableDataContext

Submits an UpdateScript for execution on the DataContext. Since implementations of the DataContext vary quite a lot, there is no golden rule as to how an update script will be executed. But the implementors should strive towards handling an UpdateScript as a single transactional change to the data store.

Specified by:

executeUpdate in interface UpdateableDataContext

Parameters:

update - the update script to execute

Returns:

a summary of the updates performed

getWriteConcernAdvisor

public WriteConcernAdvisor getWriteConcernAdvisor()

Gets the WriteConcernAdvisor to use on executeUpdate(UpdateScript) calls.

setWriteConcernAdvisor

public void setWriteConcernAdvisor(WriteConcernAdvisor writeConcernAdvisor)

Sets a global WriteConcern advisor to use on executeUpdate(UpdateScript).

getMongoDb

public com.mongodb.client.MongoDatabase getMongoDb()

Gets the DB instance that this DataContext is backed by.

Returns:

addTable

protected void addTable(MutableTable table)