Top Description Fields Constructors Methods
org.hibernate.engine.jdbc

public Class ResultSetWrapperProxy

extends Object
implements InvocationHandler
Class Inheritance
All Implemented Interfaces
java.lang.reflect.InvocationHandler
Imports
java.lang.reflect.InvocationHandler, .Proxy, .Method, .InvocationTargetException, java.sql.ResultSet, .SQLException, org.slf4j.Logger, .LoggerFactory, org.hibernate.util.JDBCExceptionReporter
A proxy for a ResultSet delegate, responsible for locally caching the columnName-to-columnIndex resolution that has been found to be inefficient in a few vendor's drivers (i.e., Oracle and Postgres).
Authors
Steve Ebersole, Gail Badner

Field Summary

Modifier and TypeField and Description
private final ColumnNameCache
columnNameCache

private static final Logger
log

private static final Class<T>[]
PROXY_INTERFACES

private final ResultSet
rs

Constructor Summary

AccessConstructor and Description
private
ResultSetWrapperProxy(ResultSet rs, ColumnNameCache columnNameCache)

Method Summary

Modifier and TypeMethod and Description
private Object[]
buildColumnIndexMethodArgs(Object[] incomingArgs, int columnIndex)

private int

Returns:

The column index corresponding to the given column name.
findColumn(String
The column name to resolve into an index.
columnName)

Locate the column index corresponding to the given column name via the cache.

public static ResultSet

Returns:

The generated proxy.
generateProxy(ResultSet
The resultSet to wrap.
resultSet, ColumnNameCache
The cache storing data for converting column names to column indexes.
columnNameCache)

Generates a proxy wrapping the ResultSet.

public static ClassLoader

Returns:

The class loader appropriate for proxy construction.
getProxyClassLoader()

Determines the appropriate class loader to which the generated proxy should be scoped.

public Object
invoke(Object
the proxy instance that the method was invoked on
proxy, Method
the Method instance corresponding to the interface method invoked on the proxy instance. The declaring class of the Method object will be the interface that the method was declared in, which may be a superinterface of the proxy interface that the proxy class inherits the method through.
method, Object[]
an array of objects containing the values of the arguments passed in the method invocation on the proxy instance, or null if interface method takes no arguments. Arguments of primitive types are wrapped in instances of the appropriate primitive wrapper class, such as java.lang.Integer or java.lang.Boolean.
args)

Implements java.lang.reflect.InvocationHandler.invoke.

Processes a method invocation on a proxy instance and returns the result.
private Object
invokeMethod(Method method, Object[] args)

private boolean
isFirstArgColumnLabel(Method method, Object[] args)

private Method

Returns:

The corresponding method passed the column index.
locateCorrespondingColumnIndexMethod(Method
The method passed the column name
columnNameMethod)

For a given ResultSet method passed a column name, locate the corresponding method passed the same parameters but the column index.

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

columnNameCacheback to summary
private final ColumnNameCache columnNameCache
logback to summary
private static final Logger log
PROXY_INTERFACESback to summary
private static final Class<T>[] PROXY_INTERFACES
rsback to summary
private final ResultSet rs

Constructor Detail

ResultSetWrapperProxyback to summary
private ResultSetWrapperProxy(ResultSet rs, ColumnNameCache columnNameCache)

Method Detail

buildColumnIndexMethodArgsback to summary
private Object[] buildColumnIndexMethodArgs(Object[] incomingArgs, int columnIndex)
findColumnback to summary
private int findColumn(String columnName) throws SQLException

Locate the column index corresponding to the given column name via the cache.

Parameters
columnName:String

The column name to resolve into an index.

Returns:int

The column index corresponding to the given column name.

Exceptions
SQLException:
if the ResultSet object does not contain columnName or a database access error occurs
generateProxyback to summary
public static ResultSet generateProxy(ResultSet resultSet, ColumnNameCache columnNameCache)

Generates a proxy wrapping the ResultSet.

Parameters
resultSet:ResultSet

The resultSet to wrap.

columnNameCache:ColumnNameCache

The cache storing data for converting column names to column indexes.

Returns:ResultSet

The generated proxy.

getProxyClassLoaderback to summary
public static ClassLoader getProxyClassLoader()

Determines the appropriate class loader to which the generated proxy should be scoped.

Returns:ClassLoader

The class loader appropriate for proxy construction.

invokeback to summary
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable

Implements java.lang.reflect.InvocationHandler.invoke.

Doc from java.lang.reflect.InvocationHandler.invoke.

Processes a method invocation on a proxy instance and returns the result. This method will be invoked on an invocation handler when a method is invoked on a proxy instance that it is associated with.

Parameters
proxy:Object

the proxy instance that the method was invoked on

method:Method

the Method instance corresponding to the interface method invoked on the proxy instance. The declaring class of the Method object will be the interface that the method was declared in, which may be a superinterface of the proxy interface that the proxy class inherits the method through.

args:Object[]

an array of objects containing the values of the arguments passed in the method invocation on the proxy instance, or null if interface method takes no arguments. Arguments of primitive types are wrapped in instances of the appropriate primitive wrapper class, such as java.lang.Integer or java.lang.Boolean.

Returns:Object

the value to return from the method invocation on the proxy instance. If the declared return type of the interface method is a primitive type, then the value returned by this method must be an instance of the corresponding primitive wrapper class; otherwise, it must be a type assignable to the declared return type. If the value returned by this method is null and the interface method's return type is primitive, then a NullPointerException will be thrown by the method invocation on the proxy instance. If the value returned by this method is otherwise not compatible with the interface method's declared return type as described above, a ClassCastException will be thrown by the method invocation on the proxy instance.

Exceptions
Throwable:
the exception to throw from the method invocation on the proxy instance. The exception's type must be assignable either to any of the exception types declared in the throws clause of the interface method or to the unchecked exception types java.lang.RuntimeException or java.lang.Error. If a checked exception is thrown by this method that is not assignable to any of the exception types declared in the throws clause of the interface method, then an UndeclaredThrowableException containing the exception that was thrown by this method will be thrown by the method invocation on the proxy instance.
invokeMethodback to summary
private Object invokeMethod(Method method, Object[] args) throws Throwable
isFirstArgColumnLabelback to summary
private boolean isFirstArgColumnLabel(Method method, Object[] args)
locateCorrespondingColumnIndexMethodback to summary
private Method locateCorrespondingColumnIndexMethod(Method columnNameMethod) throws NoSuchMethodException

For a given ResultSet method passed a column name, locate the corresponding method passed the same parameters but the column index.

Parameters
columnNameMethod:Method

The method passed the column name

Returns:Method

The corresponding method passed the column index.

Exceptions
NoSuchMethodException:
Should never happen, but...