Class TrapException

java.lang.Object

org.apache.tomcat.jdbc.pool.JdbcInterceptor

org.apache.tomcat.jdbc.pool.TrapException

All Implemented Interfaces:

InvocationHandler

public class TrapException
extends JdbcInterceptor

Interceptor that translates an exception type the invoked method does not declare into a type it does, so that a call through the pool's connection proxy respects the InvocationHandler contract: the exception is re-thrown unchanged when the method declares it (a subclass of a declared type passes as well), replaced by an SQLException carrying it as the cause when the method declares SQLException, and replaced by a RuntimeException carrying it as the cause otherwise. An Error is always re-thrown as it is, including one carried by an InvocationTargetException.

The pool prepends this interceptor to the definitions parsed from jdbcInterceptors, so it heads the chain of every connection that has an interceptor chain at all; a pool configured without an interceptor list has no chain and therefore no trap. An undeclared checked exception reaching such an untrapped connection still respects the proxy contract - the JDK proxy itself turns it into an UndeclaredThrowableException - what the trap adds on top of that is the declared, JDBC-shaped exception with the original preserved as its cause.

Field Summary

Fields inherited from class JdbcInterceptor

ABORT_VAL, CLOSE_VAL, EQUALS_VAL, GETCONNECTION_VAL, HASHCODE_VAL, ISCLOSED_VAL, ISVALID_VAL, ISWRAPPERFOR_VAL, properties, TOSTRING_VAL, UNWRAP_VAL

Constructor Summary

Constructors

Constructor	Description
TrapException()	Constructs a new TrapException interceptor.

Method Summary

Modifier and Type	Method	Description
Object	invoke(Object proxy, Method method, Object[] args)	Gets invoked each time an operation on Connection is invoked.
boolean	isDeclaredException(Method m, Class<?> clazz)	Checks if the given exception class is declared in the throws clause of the specified method.
void	reset(ConnectionPool parent, PooledConnection con)	no-op for this interceptor. no state is stored.

Methods inherited from class JdbcInterceptor

compare, compare, disconnected, getNext, getProperties, isUseEquals, poolClosed, poolStarted, setNext, setProperties, setUseEquals, unregisterMBean

Methods inherited from class Object

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

Constructor Details

TrapException

public TrapException()

Constructs a new TrapException interceptor.

Method Details

invoke

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

Description copied from class: JdbcInterceptor

Gets invoked each time an operation on Connection is invoked.

The base implementation passes the call to the next interceptor in the chain. When there is no next interceptor, the call fails fast with a NullPointerException: a chain built by the pool always ends in the ProxyConnection terminal, so reaching this case means a chain was hand-built without a terminal link. Interceptors that do not answer a call themselves continue it with super.invoke(proxy, method, args).

Specified by:

invoke in interface InvocationHandler

Overrides:

invoke in class JdbcInterceptor

Throws:

Throwable

isDeclaredException

public boolean isDeclaredException(Method m,
 Class<?> clazz)

Checks if the given exception class is declared in the throws clause of the specified method.

Parameters:

m - The method to check

clazz - The exception class to look for

Returns:

true if the exception is declared, false otherwise

reset

public void reset(ConnectionPool parent,
 PooledConnection con)

no-op for this interceptor. no state is stored.

Specified by:

reset in class JdbcInterceptor

Parameters:

parent - - the connection pool owning the connection

con - - the pooled connection