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JDBC Driver for the Firebird RDBMS
/*
* $Id: PooledConnectionHandler.java 56968 2012-04-30 12:11:30Z mrotteveel $
*
* Firebird Open Source J2EE Connector - JDBC Driver
*
* Distributable under LGPL license.
* You may obtain a copy of the License at http://www.gnu.org/copyleft/lgpl.html
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* LGPL License for more details.
*
* This file was created by members of the firebird development team.
* All individual contributions remain the Copyright (C) of those
* individuals. Contributors to this file are either listed here or
* can be obtained from a CVS history command.
*
* All rights reserved.
*/
package org.firebirdsql.ds;
import static org.firebirdsql.ds.ReflectionHelper.findMethod;
import static org.firebirdsql.ds.ReflectionHelper.getAllInterfaces;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import org.firebirdsql.jdbc.FBSQLException;
import org.firebirdsql.util.SQLExceptionChainBuilder;
/**
* InvocationHandler for the logical connection returned by FBPooledConnection.
*
* Using an InvocationHandler together with a Proxy removes the need to create
* wrappers for every individual JDBC version.
*
*
* @author Mark Rotteveel
* @since 2.2
*/
class PooledConnectionHandler implements InvocationHandler {
protected static final String CLOSED_MESSAGE = "Logical connection already closed";
protected static final String FORCIBLY_CLOSED_MESSAGE = "Logical connection was forcibly closed by the connection pool";
protected final AbstractPooledConnection owner;
protected volatile Connection connection;
protected volatile Connection proxy;
protected volatile boolean forcedClose;
private final List openStatements = Collections.synchronizedList(new LinkedList());
protected PooledConnectionHandler(Connection connection, AbstractPooledConnection owner) {
this.connection = connection;
this.owner = owner;
proxy = (Connection) Proxy.newProxyInstance(getClass().getClassLoader(),
getAllInterfaces(connection.getClass()), this);
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
// Methods from object
if (method.equals(TO_STRING)) {
return "Proxy for " + connection;
}
if (method.equals(EQUALS)) {
// Using parameter proxy (and not field) on purpose as field is
// nulled after closing
return Boolean.valueOf(proxy == args[0]);
}
if (method.equals(HASH_CODE)) {
// Using parameter proxy (and not field) on purpose as field is
// nulled after closing
return Integer.valueOf(System.identityHashCode(proxy));
}
// Other methods from object
if (method.getDeclaringClass().equals(Object.class)) {
try {
return method.invoke(connection, args);
} catch (InvocationTargetException e) {
throw e.getTargetException();
}
}
// Methods from Connection
if (method.equals(CONNECTION_IS_CLOSED)) {
return Boolean.valueOf(isClosed());
}
if (isClosed() && !method.equals(CONNECTION_CLOSE)) {
String message = forcedClose ? FORCIBLY_CLOSED_MESSAGE : CLOSED_MESSAGE;
throw new FBSQLException(message, FBSQLException.SQL_STATE_CONNECTION_CLOSED);
}
try {
// Life cycle methods
if (method.equals(CONNECTION_CLOSE)) {
if (!isClosed()) {
handleClose(true);
}
return null;
}
if (method.getDeclaringClass().equals(Connection.class)
&& STATEMENT_CREATION_METHOD_NAMES.contains(method.getName())) {
Statement pstmt = (Statement) method.invoke(connection, args);
StatementHandler stmtHandler = new StatementHandler(this, pstmt);
openStatements.add(stmtHandler);
return stmtHandler.getProxy();
}
// All other methods
return method.invoke(connection, args);
} catch (InvocationTargetException ite) {
Throwable inner = ite.getTargetException();
if (inner instanceof SQLException) {
owner.fireConnectionError((SQLException) inner);
}
throw inner;
} catch (SQLException se) {
owner.fireConnectionError(se);
throw se;
}
}
/**
* Method to decide if calling rollback on the physical connection for cleanup (in handleClose()) is allowed.
*
* NOTE: This method is not involved in rollback decisions for calls to the proxy.
*
*
* @return true when calling rollback is allowed
*/
protected boolean isRollbackAllowed() throws SQLException {
return !connection.getAutoCommit();
}
/**
* Handle {@link Connection#close()} method. This implementation closes the
* connection and associated statements.
*
* @param notifyOwner
* true when connection owner should be notified of
* closure.
*
* @throws SQLException
* if underlying connection threw an exception.
*/
protected void handleClose(boolean notifyOwner) throws SQLException {
SQLExceptionChainBuilder chain = new SQLExceptionChainBuilder();
try {
closeStatements();
} catch (SQLException ex) {
chain.append(ex);
}
if (isRollbackAllowed()) {
try {
connection.rollback();
} catch (SQLException ex) {
chain.append(ex);
}
}
try {
connection.clearWarnings();
} catch (SQLException ex) {
chain.append(ex);
}
proxy = null;
connection = null;
owner.releaseConnectionHandler(this);
if (notifyOwner) {
owner.fireConnectionClosed();
}
if (chain.hasException()) {
throw chain.getException();
}
}
/**
* @return Proxy for the Connection object
*/
protected Connection getProxy() {
return proxy;
}
/**
* Closes this PooledConnectionHandler. Intended to be called by the
* ConnectionPoolDataSource when it wants to forcibly close the logical
* connection to reuse it.
*
* @throws SQLException
*/
protected void close() throws SQLException {
if (!isClosed()) {
try {
handleClose(false);
} finally {
forcedClose = true;
}
}
}
protected boolean isClosed() {
return connection == null || proxy == null;
}
protected void statementErrorOccurred(StatementHandler stmtHandler, SQLException sqle) {
// TODO: Log?, forward fatal connection related errors?
owner.fireConnectionError(sqle);
}
protected void forgetStatement(StatementHandler stmtHandler) {
openStatements.remove(stmtHandler);
}
protected void closeStatements() throws SQLException {
SQLExceptionChainBuilder chain = new SQLExceptionChainBuilder();
synchronized (openStatements) {
// Make copy as the StatementHandler close will remove itself from openStatements
List statementsCopy = new ArrayList(openStatements);
Iterator iter = statementsCopy.iterator();
while (iter.hasNext()) {
StatementHandler stmt = (StatementHandler) iter.next();
try {
stmt.close();
} catch (SQLException ex) {
chain.append(ex);
// TODO : Log, ignore, something else?
} catch (Throwable t) {
// ignore?
}
}
openStatements.clear();
}
if (chain.hasException()) {
throw chain.getException();
}
}
// Connection methods
private final static Method CONNECTION_IS_CLOSED = findMethod(Connection.class, "isClosed",
new Class[0]);
private final static Method CONNECTION_CLOSE = findMethod(Connection.class, "close",
new Class[0]);
private static final Set STATEMENT_CREATION_METHOD_NAMES;
static {
Set temp = new HashSet();
temp.add("createStatement");
temp.add("prepareCall");
temp.add("prepareStatement");
STATEMENT_CREATION_METHOD_NAMES = Collections.unmodifiableSet(temp);
}
// Object Methods
private final static Method TO_STRING = findMethod(Object.class, "toString", new Class[0]);
private final static Method EQUALS = findMethod(Object.class, "equals",
new Class[] { Object.class });
private final static Method HASH_CODE = findMethod(Object.class, "hashCode", new Class[0]);
}