Package org.postgresql

# Class Driver

java.lang.Object
org.postgresql.Driver

All Implemented Interfaces:
  `Driver`

public class Driver extends Object implements Driver
The Java SQL framework allows for multiple database drivers. Each driver should supply a class that implements the Driver interface

The DriverManager will try to load as many drivers as it can find and then for any given connection request, it will ask each driver in turn to try to connect to the target URL.

It is strongly recommended that each Driver class should be small and standalone so that the Driver class can be loaded and queried without bringing in vast quantities of supporting code.

When a Driver class is loaded, it should create an instance of itself and register it with the DriverManager. This means that a user can load and register a driver by doing Class.forName("foo.bah.Driver")

See Also:
  - `PGConnection`
  - `Driver`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Driver()`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `boolean`
  `acceptsURL(String url)`
  Returns true if the driver thinks it can open a connection to the given URL.
  `@Nullable Connection`
  `connect(String url, @Nullable Properties info)`
  Try to make a database connection to the given URL.
  `static void`
  `deregister()`
  According to JDBC specification, this driver is registered against `DriverManager` when the class is loaded.
  `int`
  `getMajorVersion()`
  `int`
  `getMinorVersion()`
  `Logger`
  `getParentLogger()`
  `DriverPropertyInfo[]`
  `getPropertyInfo(String url, Properties info)`
  The getPropertyInfo method is intended to allow a generic GUI tool to discover what properties it should prompt a human for in order to get enough information to connect to a database.
  `static SharedTimer`
  `getSharedTimer()`
  `static String`
  `getVersion()`
  Deprecated.
  use `getMajorVersion()` and `getMinorVersion()` instead
  `static boolean`
  `isRegistered()`
  `boolean`
  `jdbcCompliant()`
  Report whether the driver is a genuine JDBC compliant driver.
  `static SQLFeatureNotSupportedException`
  `notImplemented(Class<?> callClass, String functionName)`
  This method was added in v6.5, and simply throws an SQLException for an unimplemented method.
  `static @Nullable Properties`
  `parseURL(String url, @Nullable Properties defaults)`
  Constructs a new DriverURL, splitting the specified URL into its component parts.
  `static void`
  `register()`
  Register the driver against `DriverManager`.

  ### Methods inherited from class java.lang.Object

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

- ## Constructor Details

  - ### Driver

    public Driver()

- ## Method Details

  - ### connect

    public @Nullable Connection connect(String url, @Nullable Properties info) throws SQLException
    Try to make a database connection to the given URL. The driver should return "null" if it realizes it is the wrong kind of driver to connect to the given URL. This will be common, as when the JDBC driverManager is asked to connect to a given URL, it passes the URL to each loaded driver in turn.

    The driver should raise an SQLException if it is the right driver to connect to the given URL, but has trouble connecting to the database.

    The java.util.Properties argument can be used to pass arbitrary string tag/value pairs as connection arguments.

    - user - (required) The user to connect as
    - password - (optional) The password for the user
    - ssl -(optional) Use SSL when connecting to the server
    - readOnly - (optional) Set connection to read-only by default
    - charSet - (optional) The character set to be used for converting to/from the database to unicode. If multibyte is enabled on the server then the character set of the database is used as the default, otherwise the jvm character encoding is used as the default. This value is only used when connecting to a 7.2 or older server.
    - loglevel - (optional) Enable logging of messages from the driver. The value is an integer from 0 to 2 where: OFF = 0, INFO =1, DEBUG = 2 The output is sent to DriverManager.getPrintWriter() if set, otherwise it is sent to System.out.
    - compatible - (optional) This is used to toggle between different functionality as it changes across different releases of the jdbc driver code. The values here are versions of the jdbc client and not server versions. For example in 7.1 get/setBytes worked on LargeObject values, in 7.2 these methods were changed to work on bytea values. This change in functionality could be disabled by setting the compatible level to be "7.1", in which case the driver will revert to the 7.1 functionality.

    Normally, at least "user" and "password" properties should be included in the properties. For a list of supported character encoding , see http://java.sun.com/products/jdk/1.2/docs/guide/internat/encoding.doc.html Note that you will probably want to have set up the Postgres database itself to use the same encoding, with the `-E <encoding>` argument to createdb.

    Our protocol takes the forms:

          jdbc:postgresql://host:port/database?param1=val1&...

    Specified by:
      `connect` in interface `Driver`
    Parameters:
      `url` - the URL of the database to connect to
      `info` - a list of arbitrary tag/value pairs as connection arguments
    Returns:
      a connection to the URL or null if it isnt us
    Throws:
      `SQLException` - if a database access error occurs or the url is `null`
    See Also:
      - `Driver.connect(java.lang.String, java.util.Properties)`

  - ### acceptsURL

    public boolean acceptsURL(String url)
    Returns true if the driver thinks it can open a connection to the given URL. Typically, drivers will return true if they understand the subprotocol specified in the URL and false if they don't. Our protocols start with jdbc:postgresql:
    Specified by:
      `acceptsURL` in interface `Driver`
    Parameters:
      `url` - the URL of the driver
    Returns:
      true if this driver accepts the given URL
    See Also:
      - `Driver.acceptsURL(java.lang.String)`

  - ### getPropertyInfo

    public DriverPropertyInfo[] getPropertyInfo(String url, Properties info)
    The getPropertyInfo method is intended to allow a generic GUI tool to discover what properties it should prompt a human for in order to get enough information to connect to a database.

    Note that depending on the values the human has supplied so far, additional values may become necessary, so it may be necessary to iterate through several calls to getPropertyInfo

    Specified by:
      `getPropertyInfo` in interface `Driver`
    Parameters:
      `url` - the Url of the database to connect to
      `info` - a proposed list of tag/value pairs that will be sent on connect open.
    Returns:
      An array of DriverPropertyInfo objects describing possible properties. This array may be an empty array if no properties are required
    See Also:
      - `Driver.getPropertyInfo(java.lang.String, java.util.Properties)`

  - ### getMajorVersion

    public int getMajorVersion()
    Specified by:
      `getMajorVersion` in interface `Driver`

  - ### getMinorVersion

    public int getMinorVersion()
    Specified by:
      `getMinorVersion` in interface `Driver`

  - ### getVersion

    @Deprecated public static String getVersion()
    Deprecated.
    use `getMajorVersion()` and `getMinorVersion()` instead
    Returns the server version series of this driver and the specific build number.
    Returns:
      JDBC driver version

  - ### jdbcCompliant

    public boolean jdbcCompliant()
    Report whether the driver is a genuine JDBC compliant driver. A driver may only report "true" here if it passes the JDBC compliance tests, otherwise it is required to return false. JDBC compliance requires full support for the JDBC API and full support for SQL 92 Entry Level.

    For PostgreSQL, this is not yet possible, as we are not SQL92 compliant (yet).

    Specified by:
      `jdbcCompliant` in interface `Driver`

  - ### parseURL

    public static @Nullable Properties parseURL(String url, @Nullable Properties defaults)
    Constructs a new DriverURL, splitting the specified URL into its component parts.
    Parameters:
      `url` - JDBC URL to parse
      `defaults` - Default properties
    Returns:
      Properties with elements added from the url

  - ### notImplemented

    public static SQLFeatureNotSupportedException notImplemented(Class<?> callClass, String functionName)
    This method was added in v6.5, and simply throws an SQLException for an unimplemented method. I decided to do it this way while implementing the JDBC2 extensions to JDBC, as it should help keep the overall driver size down. It now requires the call Class and the function name to help when the driver is used with closed software that don't report the stack trace
    Parameters:
      `callClass` - the call Class
      `functionName` - the name of the unimplemented function with the type of its arguments
    Returns:
      PSQLException with a localized message giving the complete description of the unimplemented function

  - ### getParentLogger

    public Logger getParentLogger()
    Specified by:
      `getParentLogger` in interface `Driver`

  - ### getSharedTimer

    public static SharedTimer getSharedTimer()

  - ### register

    public static void register() throws SQLException
    Register the driver against `DriverManager`. This is done automatically when the class is loaded. Dropping the driver from DriverManager's list is possible using `deregister()` method.
    Throws:
      `IllegalStateException` - if the driver is already registered
      `SQLException` - if registering the driver fails

  - ### deregister

    public static void deregister() throws SQLException
    According to JDBC specification, this driver is registered against `DriverManager` when the class is loaded. To avoid leaks, this method allow unregistering the driver so that the class can be gc'ed if necessary.
    Throws:
      `IllegalStateException` - if the driver is not registered
      `SQLException` - if deregistering the driver fails

  - ### isRegistered

    public static boolean isRegistered()
    Returns:
      `true` if the driver is registered against `DriverManager`