Wrapper
public
interface
Wrapper
Known indirect subclasses
CallableStatement, Connection, DataSource, DatabaseMetaData, ParameterMetaData, PreparedStatement, ResultSet, ResultSetMetaData, RowSet, RowSetMetaData, Statement
| CallableStatement |
The interface used to execute SQL stored procedures.
|
| Connection |
A connection (session) with a specific
database.
|
| DataSource |
A factory for connections to the physical data source that this
DataSource object represents.
|
| DatabaseMetaData |
Comprehensive information about the database as a whole.
|
| ParameterMetaData |
An object that can be used to get information about the types
and properties for each parameter marker in a
PreparedStatement object.
|
| PreparedStatement |
An object that represents a precompiled SQL statement.
|
| ResultSet |
A table of data representing a database result set, which
is usually generated by executing a statement that queries the database.
|
| ResultSetMetaData |
An object that can be used to get information about the types
and properties of the columns in a ResultSet object.
|
| RowSet |
The interface that adds support to the JDBC API for the
JavaBeansTM component model.
|
| RowSetMetaData |
An object that contains information about the columns in a
RowSet object.
|
| Statement |
The object used for executing a static SQL statement
and returning the results it produces.
|
|
Interface for JDBC classes which provide the ability to retrieve the delegate instance when the instance
in question is in fact a proxy class.
The wrapper pattern is employed by many JDBC driver implementations to provide extensions beyond
the traditional JDBC API that are specific to a data source. Developers may wish to gain access to
these resources that are wrapped (the delegates) as proxy class instances representing the
the actual resources. This interface describes a standard mechanism to access
these wrapped resources
represented by their proxy, to permit direct access to the resource delegates.
Summary
Public methods |
|---|
abstract
boolean
|
isWrapperFor(Class<?> iface)
Returns true if this either implements the interface argument or is directly or indirectly a wrapper
for an object that does.
|
abstract
<T>
T
|
unwrap(Class<T> iface)
Returns an object that implements the given interface to allow access to
non-standard methods, or standard methods not exposed by the proxy.
|
Public methods
isWrapperFor
public abstract boolean isWrapperFor (Class<?> iface)
Returns true if this either implements the interface argument or is directly or indirectly a wrapper
for an object that does. Returns false otherwise. If this implements the interface then return true,
else if this is a wrapper then return the result of recursively calling isWrapperFor on the wrapped
object. If this does not implement the interface and is not a wrapper, return false.
This method should be implemented as a low-cost operation compared to unwrap so that
callers can use this method to avoid expensive unwrap calls that may fail. If this method
returns true then calling unwrap with the same argument should succeed.
| Parameters |
|---|
iface |
Class: a Class defining an interface. |
| Returns |
|---|
boolean |
true if this implements the interface or directly or indirectly wraps an object that does. |
| Throws |
|---|
SQLException |
if an error occurs while determining whether this is a wrapper
for an object with the given interface. |
unwrap
public abstract T unwrap (Class<T> iface)
Returns an object that implements the given interface to allow access to
non-standard methods, or standard methods not exposed by the proxy.
If the receiver implements the interface then the result is the receiver
or a proxy for the receiver. If the receiver is a wrapper
and the wrapped object implements the interface then the result is the
wrapped object or a proxy for the wrapped object. Otherwise return the
the result of calling unwrap recursively on the wrapped object
or a proxy for that result. If the receiver is not a
wrapper and does not implement the interface, then an SQLException is thrown.
| Parameters |
|---|
iface |
Class: A Class defining an interface that the result must implement. |
| Returns |
|---|
T |
an object that implements the interface. May be a proxy for the actual implementing object. |
| Throws |
|---|
SQLException |
If no object found that implements the interface |
