edu.mssm.crover.odmg.objectstore
Class Database

java.lang.Object
  |
  +--edu.mssm.crover.odmg.objectstore.Database
All Implemented Interfaces:
org.odmg.Database

public final class Database
extends java.lang.Object
implements org.odmg.Database

The interface for interacting with an ODMG database. Databases must be opened before starting any transactions that use the database and closed after ending these transactions.

A database application generally begins processing by accessing one or more critical objects and proceeding from there. These objects are root objects, because they lead to interconnected webs of other objects. The ability to name an object (using method bind) and retrieve it later by that name (using method lookup facilitates this start-up capability. A name is not explicitly defined as an attribute of an object. Naming an object also makes it persistent.

There is a single flat name scope per database; thus all names in a particular database are unique.

Version:
ODMG 3.0
Author:
David Jordan (as Java Editor of the Object Data Management Group)

Field Summary
protected  com.odi.odmg.Database db
           
static int NOT_OPEN
          The database is not open.
static int OPEN_EXCLUSIVE
          The database is open for exclusive access.
static int OPEN_READ_ONLY
          The database is opened for read-only access.
static int OPEN_READ_WRITE
          The database is opened for reading and writing.
 
Constructor Summary
Database()
           
Database(com.odi.odmg.Database a_db)
           
 
Method Summary
 void bind(java.lang.Object object, java.lang.String name)
          Associate a name with an object and make it persistent.
 void close()
          Close the database.
 void deletePersistent(java.lang.Object object)
          Deletes an object from the database.
 com.odi.odmg.Database getDatabase()
           
 java.lang.Object lookup(java.lang.String name)
          Lookup an object via its name.
 void makePersistent(java.lang.Object object)
          Make a transient object durable in the database.
 void open(java.lang.String name, int accessMode)
          Open the named database with the specified access mode.
 void unbind(java.lang.String name)
          Disassociate a name with an object
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

NOT_OPEN

public static final int NOT_OPEN
The database is not open.

See Also:
Constant Field Values

OPEN_READ_ONLY

public static final int OPEN_READ_ONLY
The database is opened for read-only access.

See Also:
Constant Field Values

OPEN_READ_WRITE

public static final int OPEN_READ_WRITE
The database is opened for reading and writing.

See Also:
Constant Field Values

OPEN_EXCLUSIVE

public static final int OPEN_EXCLUSIVE
The database is open for exclusive access.

See Also:
Constant Field Values

db

protected com.odi.odmg.Database db
Constructor Detail

Database

public Database(com.odi.odmg.Database a_db)

Database

public Database()
Method Detail

getDatabase

public com.odi.odmg.Database getDatabase()

open

public void open(java.lang.String name,
                 int accessMode)
          throws org.odmg.ODMGException
Open the named database with the specified access mode. Attempts to open a database when it has already been opened will result in the throwing of the exception DatabaseOpenException. A DatabaseNotFoundException is thrown if the database does not exist. Some implementations may throw additional exceptions that are also derived from ODMGException.

Specified by:
open in interface org.odmg.Database
Parameters:
name - The name of the database.
accessMode - The access mode, which should be one of the static fields: OPEN_READ_ONLY, OPEN_READ_WRITE, or OPEN_EXCLUSIVE.
Throws:
org.odmg.ODMGException - The database could not be opened.

close

public void close()
           throws org.odmg.ODMGException
Close the database. After you have closed a database, further attempts to access objects in the database will cause the exception DatabaseClosedException to be thrown. Some implementations may throw additional exceptions that are also derived from ODMGException.

Specified by:
close in interface org.odmg.Database
Throws:
org.odmg.ODMGException - Unable to close the database.

bind

public void bind(java.lang.Object object,
                 java.lang.String name)
          throws org.odmg.ObjectNameNotUniqueException
Associate a name with an object and make it persistent. An object instance may be bound to more than one name. Binding a previously transient object to a name makes that object persistent.

Specified by:
bind in interface org.odmg.Database
Parameters:
object - The object to be named.
name - The name to be given to the object.
Throws:
org.odmg.ObjectNameNotUniqueException - If an attempt is made to bind a name to an object and that name is already bound to an object.

lookup

public java.lang.Object lookup(java.lang.String name)
                        throws org.odmg.ObjectNameNotFoundException
Lookup an object via its name.

Specified by:
lookup in interface org.odmg.Database
Parameters:
name - The name of an object.
Returns:
The object with that name.
Throws:
org.odmg.ObjectNameNotFoundException - There is no object with the specified name.
See Also:
ObjectNameNotFoundException

unbind

public void unbind(java.lang.String name)
            throws org.odmg.ObjectNameNotFoundException
Disassociate a name with an object

Specified by:
unbind in interface org.odmg.Database
Parameters:
name - The name of an object.
Throws:
org.odmg.ObjectNameNotFoundException - No object exists in the database with that name.

makePersistent

public void makePersistent(java.lang.Object object)
Make a transient object durable in the database. It must be executed in the context of an open transaction. If the transaction in which this method is executed commits, then the object is made durable. If the transaction aborts, then the makePersistent operation is considered not to have been executed, and the target object is again transient. ClassNotPersistenceCapableException is thrown if the implementation cannot make the object persistent because of the type of the object.

Specified by:
makePersistent in interface org.odmg.Database
Parameters:
object - The object to make persistent.

deletePersistent

public void deletePersistent(java.lang.Object object)
Deletes an object from the database. It must be executed in the context of an open transaction. If the object is not persistent, then ObjectNotPersistent is thrown. If the transaction in which this method is executed commits, then the object is removed from the database. If the transaction aborts, then the deletePersistent operation is considered not to have been executed, and the target object is again in the database.

Specified by:
deletePersistent in interface org.odmg.Database
Parameters:
object - The object to delete.


Copyright @ 2003 Mount Sinai School of Medicine. All Rights Reserved.