org.objectweb.cjdbc.controller.backend
Class DatabaseBackend

java.lang.Object
  org.objectweb.cjdbc.controller.backend.DatabaseBackend

All Implemented Interfaces:

java.io.Serializable

public class DatabaseBackend

extends java.lang.Object

implements java.io.Serializable

A DatabaseBackend represents a real database backend that will have to be bound to a virtual C-JDBC database. All connections opened will use the same url but possibly different login/password.

Version:

1.0

Author:

Emmanuel Cecchet, Mathieu Peltier, Sara Bouchenak, Nicolas Modrzyk

See Also:

Serialized Form

Field Summary

private java.util.Vector	activeTransactions List of started transactions.
private java.util.HashMap	connectionManagers Connection managers for this backend.
private java.lang.String	driverClassName Database native JDBC driver class name.
private DriverCompliance	driverCompliance Driver compliance to C-JDBC requirements
private boolean	isEnabled Is this bakend enabled.
protected Trace	logger Logger instance.
private java.lang.String	name Logical name assigned to this backend.
private java.util.Vector	pendingRequests List of pending requests.
private DatabaseSchema	schema The schema of the database.
private boolean	schemaIsStatic true if schema is static.
private java.lang.String	url Real URL to access the database (JDBC URL).

Constructor Summary

DatabaseBackend(java.lang.String name, java.lang.String driverClassName, java.lang.String url, boolean isEnabled)
Creates a new DatabaseBackend instance.

Method Summary

void	addConnectionManager(java.lang.String vLogin, AbstractConnectionManager connectionManager) Adds a ConnectionManager to this backend.
void	addPendingRequest(AbstractRequest request) Adds a pending request to this backend.
void	checkDatabaseSchema() Checks that the current database schema is compatible with all schema gathered from each connection manager.
void	checkDriverCompliance() Check if the driver used by this backend is compliant with C-JDBC needs.
void	disable() Sets the database backend state to disable.
void	enable() Enables the database backend.
boolean	equals(java.lang.Object other) Two database backends are considered equal if they have the same name, URL and driver class name.
void	finalizeConnections() Releases all the connections to the database held by the connection managers.
AbstractConnectionManager	getConnectionManager(java.lang.String vLogin) Returns the ConnectionManager associated to this backend for a given virtual login.
DatabaseSchema	getDatabaseSchema() Returns the schema of this database.
java.lang.String	getDriverClassName() Returns the database native JDBC driver class name.
DriverCompliance	getDriverCompliance()
java.lang.String	getInformation() Gets information about this backend.
java.lang.String	getName() Returns the backend logical name.
java.util.Vector	getPendingRequests() Returns the list of pending requests for this backend.
java.lang.String	getURL() Returns the JDBC URL used to access the database.
java.lang.String	getXmlInformation() Get xml information about this backend.
boolean	hasTable(java.lang.String table) Returns true if this backend has the given table in its schema.
boolean	hasTables(java.util.ArrayList tables) Returns true if this backend has the given list of tables in its schema.
void	initializeConnections() Initializes the connection managers' connections.
boolean	isEnabled() Tests if this backend is enabled (active and synchronized).
boolean	isInitialized() Tests if this backend is enabled (active and synchronized).
boolean	isStartedTransaction(java.lang.Integer tid) Returns true if the specified transaction has been started on this backend (a connection has been allocated for this transaction).
boolean	removePendingRequest(AbstractRequest request) Removes a pending request from this backend.
void	setDatabaseSchema(DatabaseSchema databaseSchema, boolean isStatic) Sets the database schema.
void	startTransaction(java.lang.Integer tid) Signals that a transaction has been started on this backend.
void	stopTransaction(java.lang.Integer tid) Signals that a transaction has been stopped on this backend.

Methods inherited from class java.lang.Object

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

Field Detail

name

private java.lang.String name

Logical name assigned to this backend.

driverClassName

private java.lang.String driverClassName

Database native JDBC driver class name.

driverCompliance

private DriverCompliance driverCompliance

Driver compliance to C-JDBC requirements

url

private java.lang.String url

Real URL to access the database (JDBC URL).

isEnabled

private boolean isEnabled

Is this bakend enabled.

schema

private DatabaseSchema schema

The schema of the database.

schemaIsStatic

private boolean schemaIsStatic

true if schema is static.

connectionManagers

private java.util.HashMap connectionManagers

Connection managers for this backend.

logger

protected transient Trace logger

Logger instance.

activeTransactions

private java.util.Vector activeTransactions

List of started transactions.

pendingRequests

private java.util.Vector pendingRequests

List of pending requests.

Constructor Detail

DatabaseBackend

public DatabaseBackend(java.lang.String name,
                       java.lang.String driverClassName,
                       java.lang.String url,
                       boolean isEnabled)

Creates a new DatabaseBackend instance.

Parameters:

name - logical name assigned to this backend

driverClassName - class name of the database native JDBC driver to load

url - URL to access the database

isEnabled - true if this backend must be enabled

Method Detail

equals

public boolean equals(java.lang.Object other)

Two database backends are considered equal if they have the same name, URL and driver class name.

Parameters:

other - an object

Returns:

a boolean value

hasTables

public boolean hasTables(java.util.ArrayList tables)

Returns true if this backend has the given list of tables in its schema. The caller must ensure that the database schema has been defined, using the setDatabaseSchema(DatabaseSchema, boolean) or checkDatabaseSchema() methods.

Parameters:

tables - the list of table names (ArrayList of String) to look for

Returns:

true if all the tables are found

hasTable

public boolean hasTable(java.lang.String table)

Returns true if this backend has the given table in its schema. The caller must ensure that the database schema has been defined, using the setDatabaseSchema(DatabaseSchema, boolean) or checkDatabaseSchema()

Parameters:

table - The table name to look for

Returns:

true if tables is found in the schema

initializeConnections

public void initializeConnections()
                           throws java.sql.SQLException

Initializes the connection managers' connections. The caller must ensure that the driver has already been loaded else an exception will be thrown.

Throws:

java.sql.SQLException - if an error occurs

finalizeConnections

public void finalizeConnections()
                         throws java.sql.SQLException

Releases all the connections to the database held by the connection managers.

Throws:

java.sql.SQLException - if an error occurs

addConnectionManager

public void addConnectionManager(java.lang.String vLogin,
                                 AbstractConnectionManager connectionManager)

Adds a ConnectionManager to this backend. Note that the ConnectionManager is not initialized in this method.

Parameters:

vLogin - the virtual login corresponding to this connection manager

connectionManager - the ConnectionManager to add

startTransaction

public void startTransaction(java.lang.Integer tid)

Signals that a transaction has been started on this backend. It means that a connection has been allocated for this transaction.

Parameters:

tid - transaction identifier

stopTransaction

public void stopTransaction(java.lang.Integer tid)

Signals that a transaction has been stopped on this backend. It means that the connection has been released for this transaction.

Parameters:

tid - transaction identifier

isStartedTransaction

public boolean isStartedTransaction(java.lang.Integer tid)

Returns true if the specified transaction has been started on this backend (a connection has been allocated for this transaction).

Parameters:

tid - transaction identifier

Returns:

true if the transaction has been started

isInitialized

public final boolean isInitialized()
                            throws java.sql.SQLException

Tests if this backend is enabled (active and synchronized).

Returns:

true if this backend is enabled

Throws:

java.sql.SQLException - if an error occurs

isEnabled

public final boolean isEnabled()

Tests if this backend is enabled (active and synchronized).

Returns:

true if this backend is enabled.

enable

public void enable()

Enables the database backend. This method should only be called when the backend is synchronized with the others.

disable

public void disable()

Sets the database backend state to disable. This state is just an indication and it has no semantic effect. It is up to the request manager (especially the load balancer) to ensure that no more requests are sent to this backend.

getConnectionManager

public AbstractConnectionManager getConnectionManager(java.lang.String vLogin)

Returns the ConnectionManager associated to this backend for a given virtual login.

Parameters:

vLogin - the virtual login

Returns:

an AbstractConnectionManager instance

getDriverClassName

public java.lang.String getDriverClassName()

Returns the database native JDBC driver class name.

Returns:

the driver class name

getName

public java.lang.String getName()

Returns the backend logical name.

Returns:

the backend logical name

getPendingRequests

public java.util.Vector getPendingRequests()

Returns the list of pending requests for this backend.

Returns:

Vector of AbstractRequests

addPendingRequest

public void addPendingRequest(AbstractRequest request)

Adds a pending request to this backend. Note that the underlying vector is synchronized.

Parameters:

request - the request to add

removePendingRequest

public boolean removePendingRequest(AbstractRequest request)

Removes a pending request from this backend. Note that the underlying vector is synchronized.

Parameters:

request - the request to remove

Returns:

true if the request has been found and removed

getDatabaseSchema

public DatabaseSchema getDatabaseSchema()

Returns the schema of this database.

Returns:

the schema of this database. Returns null if the schema has not been set.

See Also:

setDatabaseSchema(org.objectweb.cjdbc.sql.schema.DatabaseSchema, boolean)

setDatabaseSchema

public void setDatabaseSchema(DatabaseSchema databaseSchema,
                              boolean isStatic)

Sets the database schema.

Parameters:

databaseSchema - the schema to set

isStatic - true if the schema should be static

See Also:

getDatabaseSchema()

checkDatabaseSchema

public void checkDatabaseSchema()

Checks that the current database schema is compatible with all schema gathered from each connection manager.

If no schema has been defined, the first gathered schema is used as the current database schema.

For each schema that is not compatible with the current schema, a warning is issued on the logger.

getDriverCompliance

public DriverCompliance getDriverCompliance()

Returns:

the driver compliance to C-JDBC requirements.

checkDriverCompliance

public void checkDriverCompliance()
                           throws java.sql.SQLException

Check if the driver used by this backend is compliant with C-JDBC needs.

Throws:

java.sql.SQLException - if the driver is not compliant

getURL

public java.lang.String getURL()

Returns the JDBC URL used to access the database.

Returns:

a JDBC URL

getXmlInformation

public java.lang.String getXmlInformation()

Get xml information about this backend.

Returns:

xml formatted information on this database backend.

getInformation

public java.lang.String getInformation()

Gets information about this backend.

Returns:

String containing information