org.vrspace.server
Class DB

java.lang.Object
  org.vrspace.server.DB

Direct Known Subclasses:

DBCache, SQLDB, TextDB

public abstract class DB

extends java.lang.Object

Database class

Field Summary

DBCache

cache this keeps reference to cache

Constructor Summary

DB()

Method Summary

abstract void	commit() Commit changes.
abstract void	connect(java.lang.String url) connect to the database
abstract java.lang.String	create(java.lang.String name) create a new database if does not exist
abstract void	delete(java.lang.Object obj) From the table obj.getClass().getName() deletes the row having db_id == obj.db_id
abstract void	disconnect() Disconnect from the database
abstract java.lang.Object	get(java.lang.Object obj) Return database object from table obj.getClass().getName() having db_id = obj.db_id
abstract java.lang.Object	get(java.lang.String className, long id) Returns the object having id == obj.db_id
abstract java.lang.Object	get(java.lang.String className, java.lang.String field, java.lang.Object value) Returns the object of className class having field == value
abstract java.lang.Object[]	getAll(java.lang.String className) Returns all members of the class
abstract java.lang.String[]	getClasses() Returns all VRObject Classes stored in the database.
abstract java.lang.Object[]	getRange(java.lang.Object o1, java.lang.Object o2) Returns Object[] between o1 and o2 Class must have comparator() method to be searchable.
abstract java.lang.Object[]	getRange(java.lang.String className, java.lang.String field, java.lang.Object value) Returns the object of className class having field == value
void	load(java.io.File file) Loads file content into the database
void	load(java.io.Reader in) Loads stream content into the database
void	load(java.lang.String url) Loads file content into the db.
abstract void	put(java.lang.Object obj) Stores obj into database Logic: - all the public fields are stored - database table: obj.getClass().getName() - create table if does not exist
abstract void	update(Request r) A request is a change to one field.

Methods inherited from class java.lang.Object

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

Field Detail

cache

public DBCache cache

this keeps reference to cache

Constructor Detail

DB

public DB()

Method Detail

create

public abstract java.lang.String create(java.lang.String name)
                                 throws java.lang.Exception

create a new database if does not exist

Parameters:

name - Database name

Returns:

String to use as parameter to connect()

Throws:

java.lang.Exception

See Also:

connect(java.lang.String)

connect

public abstract void connect(java.lang.String url)
                      throws java.lang.Exception

connect to the database

Throws:

java.lang.Exception

disconnect

public abstract void disconnect()

Disconnect from the database

commit

public abstract void commit()

Commit changes. Should NOT be synchronized.

get

public abstract java.lang.Object get(java.lang.Object obj)
                              throws java.lang.Exception

Return database object from table obj.getClass().getName() having db_id = obj.db_id

Throws:

java.lang.Exception

get

public abstract java.lang.Object get(java.lang.String className,
                                     long id)
                              throws java.lang.Exception

Returns the object having id == obj.db_id

Throws:

java.lang.Exception

get

public abstract java.lang.Object get(java.lang.String className,
                                     java.lang.String field,
                                     java.lang.Object value)
                              throws java.lang.Exception

Returns the object of className class having field == value

Throws:

java.lang.Exception

getRange

public abstract java.lang.Object[] getRange(java.lang.String className,
                                            java.lang.String field,
                                            java.lang.Object value)
                                     throws java.lang.Exception

Returns the object of className class having field == value

Throws:

java.lang.Exception

getRange

public abstract java.lang.Object[] getRange(java.lang.Object o1,
                                            java.lang.Object o2)
                                     throws java.lang.Exception

Returns Object[] between o1 and o2 Class must have comparator() method to be searchable.

Throws:

java.lang.Exception

getAll

public abstract java.lang.Object[] getAll(java.lang.String className)
                                   throws java.lang.Exception

Returns all members of the class

Throws:

java.lang.Exception

getClasses

public abstract java.lang.String[] getClasses()
                                       throws java.lang.Exception

Returns all VRObject Classes stored in the database.

Throws:

java.lang.Exception

delete

public abstract void delete(java.lang.Object obj)
                     throws java.lang.Exception

From the table obj.getClass().getName() deletes the row having db_id == obj.db_id

Throws:

java.lang.Exception

put

public abstract void put(java.lang.Object obj)
                  throws java.lang.Exception

Stores obj into database Logic: - all the public fields are stored - database table: obj.getClass().getName() - create table if does not exist

Throws:

java.lang.Exception

update

public abstract void update(Request r)
                     throws java.lang.Exception

A request is a change to one field. This method allows optimal database update.

Throws:

java.lang.Exception

load

public void load(java.lang.String url)
          throws java.lang.Exception

Loads file content into the db. Default protocol for url is 'file'

Throws:

java.lang.Exception

load

public void load(java.io.Reader in)
          throws java.lang.Exception

Loads stream content into the database

Throws:

java.lang.Exception

load

public void load(java.io.File file)
          throws java.lang.Exception

Loads file content into the database

Throws:

java.lang.Exception