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/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.java.ao.db;
import net.java.ao.Disposable;
import net.java.ao.DisposableDataSource;
import org.slf4j.Logger;
import javax.sql.DataSource;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Map;
import java.util.Objects;
import static com.google.common.collect.Maps.newHashMap;
import static java.lang.reflect.Proxy.newProxyInstance;
import static java.sql.ResultSet.TYPE_FORWARD_ONLY;
import static java.sql.Types.BIGINT;
import static org.slf4j.LoggerFactory.getLogger;
/**
* The NuoDB JDBC Driver supports ResultSet.TYPE_FORWARD_ONLY currently. The NuoDB data source handler intercepts
* invocations of methods, which create SQL statements and forcibly overrides result set type to
* {@link java.sql.ResultSet.TYPE_FORWARD_ONLY}. These are methods intercepted by the handler:
*
* - Statement createStatement(int resultSetType, int resultSetConcurrency);
* - PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency);
* - CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency);
*
*
* @author Sergey Bushik
*/
public class NuoDBDisposableDataSourceHandler {
private static final ClassLoader CLASS_LOADER = NuoDBDisposableDataSourceHandler.class.getClassLoader();
/**
* Creates reflection proxy for the specified NuoDB data source
*
* @param dataSource to intercept invocations
* @return disposable data source
*/
public static DisposableDataSource newInstance(DataSource dataSource) {
return newInstance(dataSource, null);
}
public static DisposableDataSource newInstance(DataSource dataSource, Disposable disposable) {
return (DisposableDataSource) newProxy(
new Class[]{DisposableDataSource.class},
new DelegatingDisposableDataSourceHandler(dataSource, disposable));
}
private static Object newProxy(Class[] interfaces, InvocationHandler invocationHandler) {
Object proxy = newProxyInstance(CLASS_LOADER, interfaces, invocationHandler);
return proxy;
}
/**
* Intercepts dispose() and getConnection() methods
*/
static class DelegatingDisposableDataSourceHandler extends DelegatingInvocationHandler {
private static final String GET_CONNECTION = "getConnection";
private static final String DISPOSE = "dispose";
private Disposable disposable;
public DelegatingDisposableDataSourceHandler(DataSource dataSource, Disposable disposable) {
super(dataSource);
this.disposable = disposable;
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
String name = method.getName();
Class[] parameterTypes = method.getParameterTypes();
Object result = null;
// call dispose
if (name.equals(DISPOSE) && parameterTypes.length == 0 && disposable != null) {
disposable.dispose();
// proxy getConnection() invocation
} else if (name.equals(GET_CONNECTION)) {
Connection connection = (Connection) delegate(method, args);
result = newProxy(new Class[]{Connection.class},
new DelegatingConnectionHandler(connection));
} else {
result = delegate(method, args);
}
return result;
}
}
/**
* The handler, where result set type actually forcibly changed to those supported by NuoDB JDBC Driver.
*/
static class DelegatingConnectionHandler extends DelegatingInvocationHandler {
public static final String CREATE_STATEMENT = "createStatement";
public static final String PREPARE_STATEMENT = "prepareStatement";
public static final String PREPARE_CALL = "prepareCall";
public DelegatingConnectionHandler(Connection connection) {
super(connection);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
String name = method.getName();
Class[] parameterTypes = method.getParameterTypes();
Class statement = null;
Integer resultSetTypeArgIndex = null;
// change result set type to java.sql.Types.TYPE_FORWARD_ONLY
if (name.equals(CREATE_STATEMENT)) {
statement = Statement.class;
// Statement createStatement(int resultSetType, int resultSetConcurrency);
// Statement createStatement(int resultSetType, int resultSetConcurrency,
// int resultSetHoldability) throws SQLException;
if (parameterTypes.length >= 2) {
resultSetTypeArgIndex = 0;
}
} else if (name.equals(PREPARE_STATEMENT)) {
// PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency);
// PreparedStatement prepareStatement(String sql, int resultSetType,
// int resultSetConcurrency, int resultSetHoldability);
statement = PreparedStatement.class;
if (parameterTypes.length >= 3) {
resultSetTypeArgIndex = 1;
}
} else if (name.equals(PREPARE_CALL)) {
statement = CallableStatement.class;
// CallableStatement prepareCall(String sql, int resultSetType, int resultSetConcurrency);
// CallableStatement prepareCall(String sql, int resultSetType,
// int resultSetConcurrency, int resultSetHoldability) throws SQLException;
if (parameterTypes.length >= 3) {
resultSetTypeArgIndex = 1;
}
}
if (resultSetTypeArgIndex != null &&
((Integer) args[resultSetTypeArgIndex]) != TYPE_FORWARD_ONLY) {
args[resultSetTypeArgIndex] = TYPE_FORWARD_ONLY;
if (logger.isTraceEnabled()) {
logger.trace("Result set type changed to forward only");
}
}
Object result = super.invoke(proxy, method, args);
return statement != null ? newProxy(new Class[]{statement},
new DelegatingStatementHandler((Connection) proxy, (Statement) result)) : result;
}
}
static class DelegatingStatementHandler extends DelegatingInvocationHandler {
private static final String GET_CONNECTION = "getConnection";
private static final String GET_RESULT_SET = "getResultSet";
private static final String EXECUTE_QUERY = "executeQuery";
private Connection connection;
public DelegatingStatementHandler(Connection connection, Statement statement) {
super(statement);
this.connection = connection;
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
String name = method.getName();
Object result;
// proxy connection
if (name.equals(GET_CONNECTION)) {
result = connection;
// proxy result set
} else if (name.equals(EXECUTE_QUERY) || name.equals(GET_RESULT_SET)) {
result = newProxy(new Class[]{ResultSet.class},
new DelegatingResultSetHandler((Statement) proxy,
(ResultSet) super.invoke(proxy, method, args)));
} else {
result = super.invoke(proxy, method, args);
}
return result;
}
}
static class DelegatingResultSetHandler extends DelegatingInvocationHandler {
private static final String GET_STATEMENT = "getStatement";
private static final String GET_OBJECT = "getObject";
private ResultSetMetaData metaData;
private Statement statement;
private Map columns;
protected DelegatingResultSetHandler(Statement statement, ResultSet resultSet) throws SQLException {
super(resultSet);
this.statement = statement;
this.metaData = target.getMetaData();
int count = metaData.getColumnCount();
Map columns = newHashMap();
for (int index = 0; index < count; index++) {
int column = index + 1;
columns.put(metaData.getColumnName(column), column);
}
this.columns = columns;
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
String name = method.getName();
Object result;
// proxy statement
if (name.equals(GET_STATEMENT)) {
result = statement;
// change resultSet.getObject() for BIGINT to return resultSet.getLong()
} else if (name.equals(GET_OBJECT)) {
Integer column = null;
if (method.getParameterTypes()[0].equals(String.class)) {
column = columns.get(args[0]);
} else {
column = (Integer) args[0];
}
// fixes get object for java.sql.Types.BIGINT to return long
if (column != null && metaData.getColumnType(column) == BIGINT) {
result = target.getLong(column);
} else {
result = super.invoke(proxy, method, args);
}
} else {
result = super.invoke(proxy, method, args);
}
return result;
}
}
/**
* Base delegating invocation handler
*/
static class DelegatingInvocationHandler implements InvocationHandler {
protected final Logger logger = getLogger(getClass());
protected final T target;
protected DelegatingInvocationHandler(T target) {
this.target = Objects.requireNonNull(target, "target can't be null");
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
return delegate(method, args);
}
protected Object delegate(Method method, Object[] args) throws Throwable {
final Method m = target.getClass().getMethod(method.getName(), method.getParameterTypes());
m.setAccessible(true);
try {
return m.invoke(target, args);
} catch (IllegalAccessException exception) {
// avoid UndeclaredThrowableExceptions
throw new RuntimeException(exception);
} catch (IllegalArgumentException exception) {
// avoid UndeclaredThrowableExceptions
throw new RuntimeException(exception);
} catch (InvocationTargetException exception) {
// avoid UndeclaredThrowableExceptions
throw exception.getCause();
}
}
}
}