Class StatementFinalizer

java.lang.Object

org.apache.tomcat.jdbc.pool.JdbcInterceptor

org.apache.tomcat.jdbc.pool.interceptor.AbstractCreateStatementInterceptor

org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer

All Implemented Interfaces:

InvocationHandler

public class StatementFinalizer
extends AbstractCreateStatementInterceptor

Keeps track of statements associated with a connection and invokes close upon Connection.close() Useful for applications that don't close the associated statements after being done with a connection.

A statement is tracked with a strong reference until it is closed: an application that forgot about a statement is exactly the case the interceptor exists for, so finalisation must not depend on that statement still being reachable when the connection is returned. Statements that the application does close are forgotten by the returned proxy at the moment close() completes, keeping the tracked list bounded by the statements that are genuinely still open and closed through that handle. (The removal cannot observe a close that reaches the statement by another route: an interceptor placed outside this one may swallow the statement's close(), e.g. a statement cache recycling instead of closing, and a statement the application closes through the driver handle that unwrap hands back never passes through this proxy; such entries are simply reclaimed at the connection return, where the renewed close meets a statement already closed as a harmless no-op, as they were before.)

Tracked statements are handed to the application as proxies implementing the standard JDBC statement interfaces, as is the statement facade the pool always installs in front of this interceptor and as are the proxies of the other statement-wrapping interceptors; the driver's own statement class is therefore not reachable by casting. The Wrapper methods are delegated to the driver, and unwrap is the supported way to reach driver-specific statement methods. A statement the application reaches that way is still tracked here and is closed, like any other tracked statement, when the connection is returned - unless an interceptor listed after this one recycles the statement instead of closing it, as a statement cache beneath this interceptor does.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	StatementFinalizer.CloseAwareProxy	Thin proxy around a tracked statement.
protected class	StatementFinalizer.StatementEntry	Entry that tracks a statement and its allocation stack.

Field Summary

Fields

Modifier and Type	Field	Description
protected final List<StatementFinalizer.StatementEntry>	statements	Statements created on the associated connection that have not been closed yet.
protected final Object	statementsLock	Monitor guarding statements.

Fields inherited from class AbstractCreateStatementInterceptor

constructors, CREATE_STATEMENT, CREATE_STATEMENT_IDX, EXECUTE, EXECUTE_BATCH, EXECUTE_LARGE_BATCH, EXECUTE_LARGE_UPDATE, EXECUTE_QUERY, EXECUTE_TYPES, EXECUTE_UPDATE, GET_GENERATED_KEYS, GET_RESULTSET, GET_STATEMENT, PREPARE_CALL, PREPARE_CALL_IDX, PREPARE_STATEMENT, PREPARE_STATEMENT_IDX, RESULTSET_IDX, STATEMENT_TYPE_COUNT, STATEMENT_TYPES

Modifier and Type	Field	Description
protected static final Constructor<?>[]	constructors	the constructors that are used to create statement proxies.
protected static final String	CREATE_STATEMENT	Connection.createStatement()
protected static final int	CREATE_STATEMENT_IDX	Index for AbstractCreateStatementInterceptor.CREATE_STATEMENT in AbstractCreateStatementInterceptor.STATEMENT_TYPES
protected static final String	EXECUTE	Statement.execute(String)
protected static final String	EXECUTE_BATCH	Statement.executeBatch()
protected static final String	EXECUTE_LARGE_BATCH	Statement.executeLargeBatch()
protected static final String	EXECUTE_LARGE_UPDATE	Statement.executeLargeUpdate(String) and its overloads, and PreparedStatement.executeLargeUpdate()
protected static final String	EXECUTE_QUERY	Statement.executeQuery(String)
protected static final String[]	EXECUTE_TYPES	Array of execute type method names
protected static final String	EXECUTE_UPDATE	Statement.executeUpdate(String)
protected static final String	GET_GENERATED_KEYS	Statement.getGeneratedKeys()
protected static final String	GET_RESULTSET	Statement.getResultSet()
protected static final String	GET_STATEMENT	ResultSet.getStatement()
protected static final String	PREPARE_CALL	Connection.prepareCall(String)
protected static final int	PREPARE_CALL_IDX	Index for AbstractCreateStatementInterceptor.PREPARE_CALL in AbstractCreateStatementInterceptor.STATEMENT_TYPES
protected static final String	PREPARE_STATEMENT	Connection.prepareStatement(String)
protected static final int	PREPARE_STATEMENT_IDX	Index for AbstractCreateStatementInterceptor.PREPARE_STATEMENT in AbstractCreateStatementInterceptor.STATEMENT_TYPES
protected static final int	RESULTSET_IDX	Index for AbstractCreateStatementInterceptor.GET_STATEMENT in AbstractCreateStatementInterceptor.STATEMENT_TYPES
protected static final int	STATEMENT_TYPE_COUNT	Count of statement types in AbstractCreateStatementInterceptor.STATEMENT_TYPES
protected static final String[]	STATEMENT_TYPES	Array of statement type method names

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

Modifier and Type	Field	Description
static final String	ABORT_VAL	Connection.abort(java.util.concurrent.Executor) method name
static final String	CLOSE_VAL	Connection.close() method name
static final String	EQUALS_VAL	Object.equals(Object)
static final String	GETCONNECTION_VAL	PooledConnection.getConnection() method name
static final String	HASHCODE_VAL	Object.hashCode()
static final String	ISCLOSED_VAL	Connection.isClosed() method name
static final String	ISVALID_VAL	Connection.isValid(int) method name
static final String	ISWRAPPERFOR_VAL	Wrapper.isWrapperFor(Class) method name
protected Map<String, PoolProperties.InterceptorProperty>	properties	Properties for this interceptor.
static final String	TOSTRING_VAL	Object.toString() method name
static final String	UNWRAP_VAL	Wrapper.unwrap(Class) method name

Constructor Summary

Constructors

Constructor	Description
StatementFinalizer()	Default constructor.

Method Summary

Modifier and Type	Method	Description
void	closeInvoked()	Method invoked when the operation Connection.close() is invoked.
Object	createStatement(Object proxy, Method method, Object[] args, Object statement, long time)	This method will be invoked after a successful statement creation.
void	reset(ConnectionPool parent, PooledConnection con)	no-op for this interceptor. no state is stored.
void	setProperties(Map<String, PoolProperties.InterceptorProperty> properties)	Called during the creation of an interceptor The properties can be set during the configuration of an interceptor Override this method to perform type casts between string values and object properties

Methods inherited from class AbstractCreateStatementInterceptor

getConstructor, invoke, isExecute, isStatement, process

Modifier and Type	Method	Description
protected Constructor<?>	getConstructor(int idx, Class<?> clazz)	Creates a constructor for a proxy class, if one doesn't already exist.
Object	invoke(Object proxy, Method method, Object[] args)	Gets invoked each time an operation on Connection is invoked.
protected boolean	isExecute(Method method, boolean process)	Returns true if the method that is being invoked matches one of the execute types.
protected boolean	isStatement(Method method, boolean process)	Returns true if the method that is being invoked matches one of the statement types.
protected boolean	process(String[] names, Method method, boolean process)	Returns true if the method that is being invoked matches one of the method names passed in

Methods inherited from class JdbcInterceptor

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

Modifier and Type	Method	Description
boolean	compare(String methodName, Method method)	Compares a method name (String) to a method (Method) JdbcInterceptor.compare(String,String) Uses reference comparison unless the useEquals property is set to true
boolean	compare(String name1, String name2)	Performs a string comparison, using references unless the useEquals property is set to true.
void	disconnected(ConnectionPool parent, PooledConnection con, boolean finalizing)	Called when Connection.close() is called on the underlying connection.
JdbcInterceptor	getNext()	Returns the next interceptor in the chain
Map<String, PoolProperties.InterceptorProperty>	getProperties()	Returns the properties configured for this interceptor
boolean	isUseEquals()	True if the compare method uses the Object.equals(Object) method, false if comparison is done on a reference level.
void	poolClosed(ConnectionPool pool)	This method is invoked by a connection pool when the pool is closed.
void	poolStarted(ConnectionPool pool)	This method is invoked by a connection pool when the pool is first started up, usually when the first connection is requested.
void	setNext(JdbcInterceptor next)	configures the next interceptor in the chain
void	setUseEquals(boolean useEquals)	Set to true if string comparisons (for the JdbcInterceptor.compare(String, Method) and JdbcInterceptor.compare(String, String) methods) should use the Object.equals(Object) method The default is false

Methods inherited from class Object

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

Field Details

statements

protected final List<StatementFinalizer.StatementEntry> statements

Statements created on the associated connection that have not been closed yet. Every access must be guarded by statementsLock.

statementsLock

protected final Object statementsLock

Monitor guarding statements. The pool's cleaner thread may clear the list (through reset(ConnectionPool, PooledConnection)) while a borrower is still creating or closing statements on an abandoned connection, so subclasses that access the list must hold this lock as well.

Constructor Details

StatementFinalizer

public StatementFinalizer()

Default constructor.

Method Details

createStatement

public Object createStatement(Object proxy,
 Method method,
 Object[] args,
 Object statement,
 long time)

Description copied from class: AbstractCreateStatementInterceptor

This method will be invoked after a successful statement creation. This method can choose to return a wrapper around the statement or return the statement itself. If this method returns a wrapper then it should return a wrapper object that implements one of the following interfaces. Statement, PreparedStatement or CallableStatement

Specified by:

createStatement in class AbstractCreateStatementInterceptor

Parameters:

proxy - the actual proxy object

method - the method that was called. It will be one of the methods defined in AbstractCreateStatementInterceptor.STATEMENT_TYPES

args - the arguments to the method

statement - the statement that the underlying connection created

time - Elapsed time

Returns:

a Statement object

closeInvoked

public void closeInvoked()

Description copied from class: AbstractCreateStatementInterceptor

Method invoked when the operation Connection.close() is invoked.

Specified by:

closeInvoked in class AbstractCreateStatementInterceptor

setProperties

public void setProperties(Map<String, PoolProperties.InterceptorProperty> properties)

Description copied from class: JdbcInterceptor

Called during the creation of an interceptor The properties can be set during the configuration of an interceptor Override this method to perform type casts between string values and object properties

Overrides:

setProperties in class JdbcInterceptor

Parameters:

properties - The properties

reset

public void reset(ConnectionPool parent,
 PooledConnection con)

Description copied from class: AbstractCreateStatementInterceptor

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

Overrides:

reset in class AbstractCreateStatementInterceptor

Parameters:

parent - - the connection pool owning the connection

con - - the pooled connection