de.mguennewig.pobjects.memdb
Class MemoryContainer

java.lang.Object
  de.mguennewig.pobjects.AbstractContainer
      de.mguennewig.pobjects.memdb.MemoryContainer

All Implemented Interfaces:

Container

public class MemoryContainer
extends AbstractContainer

A simple object container that simulates a database, but stores everything in memory.

This container is more based on a feasibility study and was quite helpful to cleanup the Container and Query infrastructure, then to be a useful tool.

The implementation is very naive and in no way optimized for speed or memory usage. Possible improvements:

• add plans for query processing
• optimize query
• ...

SelectExpr and ViewDecl are not supported.

Author:

Michael Günnewig

Field Summary

Fields inherited from interface de.mguennewig.pobjects.Container

SUPPORTS_BOOLEAN, SUPPORTS_INHERITS, SUPPORTS_JOIN, SUPPORTS_LIMIT_OFFSET, SUPPORTS_ORACLE_JOIN, SUPPORTS_SQL99_JOIN, USE_ARRAY_FOR_LOB, USE_STREAM_TO_INSERT_LOB

Constructor Summary

MemoryContainer(PObjDictionary dict, java.lang.String schema)
Creates a new MemoryContainer.

Method Summary

void	close()
void	commitTransaction() Commits all statements since the last Container.beginTransaction().
int	deleteAll(ClassDecl te) Deletes all entries within the specified table.
int	deleteAll(ClassDecl te, Column fk, java.lang.Object value) Deletes all entries within the specified table whose foreign key fk equals the given value.
void	deleteObject(PObject obj) Deletes the given persistent object from the database.
boolean	deleteRecord(Record obj)
void	dump(java.io.PrintStream out, java.lang.String name)
int	getCapabilities() Returns the capabilities of the DBMS.
java.lang.String	getSequenceCurrentValue(Sequence seq) Returns the current value of the given sequence.
java.lang.String	getSequenceNextValue(Sequence seq) Returns a new value of the given sequence.
java.lang.String	insertObject(PObject obj) Inserts the given object into the database.
boolean	insertRecord(Record obj)
EvalContext	newEvalContext(int numColumns)
Query	newQuery() Creates a new empty query.
void	reset() Resets the container.
void	retrieveData(PObject obj) Retrieves the data for the given persistent object from the database.
void	rollbackTransaction() Rolls back all statements since the last Container.beginTransaction().
void	updateObject(PObject obj) Updates the given persistent object in the database.

Methods inherited from class de.mguennewig.pobjects.AbstractContainer

beginTransaction, createObject, deleteAll, getClassDecl, getClassDecls, getData, getDictionary, getObject, getObject, getQualifiedName, getSchema, getTableExpr, isStrictMode, makePersistent, newQuery, newQuery, newQuery, newQuery, newQuery, newQuery, newQuery, newQuery, notifyChange, setStrictMode, storeAll, supportsBoolean, supportsInherits, supportsLimitOffset, supportsOracleJoin, supportsSQL99Join, useArrayForLob, useStreamToInsertLob

Methods inherited from class java.lang.Object

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

Constructor Detail

MemoryContainer

public MemoryContainer(PObjDictionary dict,
                       java.lang.String schema)

Creates a new MemoryContainer.

Method Detail

close

public void close()

getCapabilities

public int getCapabilities()

Returns the capabilities of the DBMS.

See Also:

"The SUPPORTS_* constants."

getSequenceCurrentValue

public java.lang.String getSequenceCurrentValue(Sequence seq)
                                         throws PObjSQLException

Returns the current value of the given sequence.

Throws:

PObjSQLException - if any database error occurs.

getSequenceNextValue

public java.lang.String getSequenceNextValue(Sequence seq)
                                      throws PObjSQLException

Returns a new value of the given sequence.

Throws:

PObjSQLException - if any database error occurs.

insertObject

public java.lang.String insertObject(PObject obj)
                              throws PObjConstraintException,
                                     PObjSQLException

Inserts the given object into the database.

Throws:

PObjConstraintException - if a database constraint will be violated.

PObjSQLException - if any other database error occurs.

updateObject

public void updateObject(PObject obj)
                  throws PObjConstraintException,
                         PObjSQLException

Updates the given persistent object in the database.

Throws:

PObjConstraintException - if a database constraint will be violated.

PObjSQLException - if any other database error occurs.

See Also:

PObject.isPersistent()

deleteObject

public void deleteObject(PObject obj)
                  throws PObjConstraintException,
                         PObjSQLException

Deletes the given persistent object from the database.

Throws:

PObjConstraintException - if a database constraint will be violated.

PObjSQLException - if any other database error occurs.

See Also:

PObject.isPersistent()

insertRecord

public boolean insertRecord(Record obj)
                     throws PObjConstraintException,
                            PObjSQLException

Throws:

PObjConstraintException

PObjSQLException

deleteRecord

public boolean deleteRecord(Record obj)
                     throws PObjConstraintException,
                            PObjSQLException

Throws:

PObjConstraintException

PObjSQLException

retrieveData

public void retrieveData(PObject obj)

Retrieves the data for the given persistent object from the database.

commitTransaction

public void commitTransaction()
                       throws PObjSQLException

Commits all statements since the last Container.beginTransaction().

If Container.isStrictMode() yields false then just a warning for each dirty object is written, otherwise an exception is raised.

Specified by:

commitTransaction in interface Container

Overrides:

commitTransaction in class AbstractContainer

Throws:

PObjSQLException - if the DBMS in unable to finish the current transaction by committing it or if an modified but unstored object is detected while in strict mode.

rollbackTransaction

public void rollbackTransaction()
                         throws PObjSQLException

Rolls back all statements since the last Container.beginTransaction().

The in-memory data will be reverted also as far as possible.

Specified by:

rollbackTransaction in interface Container

Overrides:

rollbackTransaction in class AbstractContainer

Throws:

PObjSQLException - if the DBMS is unable to stop the current transaction by rolling back all made changes within it.

See Also:

PObject.revert()

deleteAll

public int deleteAll(ClassDecl te)
              throws PObjSQLException,
                     PObjConstraintException

Deletes all entries within the specified table.

NOTE: The objects which represent a row of this table or refer to rows within it aren't updated. So the best way to ensure consistency is to finish the current active transaction before calling this method and afterwards doing a Container.reset().

Throws:

PObjSQLException - if any other database error occurs.

PObjConstraintException - if a database constraint will be violated.

deleteAll

public int deleteAll(ClassDecl te,
                     Column fk,
                     java.lang.Object value)
              throws PObjSQLException,
                     PObjConstraintException

Deletes all entries within the specified table whose foreign key fk equals the given value.

NOTE: The objects which represent a row of this table or refer to rows within it aren't updated. So the best way to ensure consistency is to finish the current active transaction before calling this method and afterwards doing a Container.reset().

Throws:

PObjSQLException - if any other database error occurs.

PObjConstraintException - if a database constraint will be violated.

reset

public void reset()

Resets the container.

Use this method to forget all changes made to any object.

NOTE: Any running transaction will be rolled back.

Specified by:

reset in interface Container

Overrides:

reset in class AbstractContainer

See Also:

Container.rollbackTransaction()

newEvalContext

public EvalContext newEvalContext(int numColumns)

newQuery

public Query newQuery()

Creates a new empty query.

dump

public final void dump(java.io.PrintStream out,
                       java.lang.String name)