/*
* Copyright 2002-2010 the original author or authors.
*
* 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 org.springframework.jdbc.support;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.WeakHashMap;
import javax.sql.DataSource;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;
import org.springframework.util.PatternMatchUtils;
/**
* Factory for creating {@link SQLErrorCodes} based on the
* "databaseProductName" taken from the {@link java.sql.DatabaseMetaData}.
*
* <p>Returns <code>SQLErrorCodes</code> populated with vendor codes
* defined in a configuration file named "sql-error-codes.xml".
* Reads the default file in this package if not overridden by a file in
* the root of the class path (for example in the "/WEB-INF/classes" directory).
*
* @author Thomas Risberg
* @author Rod Johnson
* @author Juergen Hoeller
* @see java.sql.DatabaseMetaData#getDatabaseProductName()
*/
public class SQLErrorCodesFactory {
/**
* The name of custom SQL error codes file, loading from the root
* of the class path (e.g. from the "/WEB-INF/classes" directory).
*/
public static final String SQL_ERROR_CODE_OVERRIDE_PATH = "sql-error-codes.xml";
/**
* The name of default SQL error code files, loading from the class path.
*/
public static final String SQL_ERROR_CODE_DEFAULT_PATH = "org/springframework/jdbc/support/sql-error-codes.xml";
private static final Log logger = LogFactory.getLog(SQLErrorCodesFactory.class);
/**
* Keep track of a single instance so we can return it to classes that request it.
*/
private static final SQLErrorCodesFactory instance = new SQLErrorCodesFactory();
/**
* Return the singleton instance.
*/
public static SQLErrorCodesFactory getInstance() {
return instance;
}
/**
* Map to hold error codes for all databases defined in the config file.
* Key is the database product name, value is the SQLErrorCodes instance.
*/
private final Map errorCodesMap;
/**
* Map to cache the SQLErrorCodes instance per DataSource.
* Key is the DataSource, value is the SQLErrorCodes instance.
*/
private final Map dataSourceCache = new WeakHashMap(16);
/**
* Create a new instance of the {@link SQLErrorCodesFactory} class.
* <p>Not public to enforce Singleton design pattern. Would be private
* except to allow testing via overriding the
* {@link #loadResource(String)} method.
* <p><b>Do not subclass in application code.</b>
* @see #loadResource(String)
*/
protected SQLErrorCodesFactory() {
Map errorCodes = null;
try {
DefaultListableBeanFactory lbf = new DefaultListableBeanFactory();
XmlBeanDefinitionReader bdr = new XmlBeanDefinitionReader(lbf);
// Load default SQL error codes.
Resource resource = loadResource(SQL_ERROR_CODE_DEFAULT_PATH);
if (resource != null && resource.exists()) {
bdr.loadBeanDefinitions(resource);
}
else {
logger.warn("Default sql-error-codes.xml not found (should be included in spring.jar)");
}
// Load custom SQL error codes, overriding defaults.
resource = loadResource(SQL_ERROR_CODE_OVERRIDE_PATH);
if (resource != null && resource.exists()) {
bdr.loadBeanDefinitions(resource);
logger.info("Found custom sql-error-codes.xml file at the root of the classpath");
}
// Check all beans of type SQLErrorCodes.
errorCodes = lbf.getBeansOfType(SQLErrorCodes.class, true, false);
if (logger.isInfoEnabled()) {
logger.info("SQLErrorCodes loaded: " + errorCodes.keySet());
}
}
catch (BeansException ex) {
logger.warn("Error loading SQL error codes from config file", ex);
errorCodes = Collections.EMPTY_MAP;
}
this.errorCodesMap = errorCodes;
}
/**
* Load the given resource from the class path.
* <p><b>Not to be overridden by application developers, who should obtain
* instances of this class from the static {@link #getInstance()} method.</b>
* <p>Protected for testability.
* @param path resource path; either a custom path or one of either
* {@link #SQL_ERROR_CODE_DEFAULT_PATH} or
* {@link #SQL_ERROR_CODE_OVERRIDE_PATH}.
* @return the resource, or <code>null</code> if the resource wasn't found
* @see #getInstance
*/
protected Resource loadResource(String path) {
return new ClassPathResource(path, getClass().getClassLoader());
}
/**
* Return the {@link SQLErrorCodes} instance for the given database.
* <p>No need for a database metadata lookup.
* @param dbName the database name (must not be <code>null</code>)
* @return the <code>SQLErrorCodes</code> instance for the given database
* @throws IllegalArgumentException if the supplied database name is <code>null</code>
*/
public SQLErrorCodes getErrorCodes(String dbName) {
Assert.notNull(dbName, "Database product name must not be null");
SQLErrorCodes sec = (SQLErrorCodes) this.errorCodesMap.get(dbName);
if (sec == null) {
for (Iterator it = this.errorCodesMap.values().iterator(); it.hasNext();) {
SQLErrorCodes candidate = (SQLErrorCodes) it.next();
if (PatternMatchUtils.simpleMatch(candidate.getDatabaseProductNames(), dbName)) {
sec = candidate;
break;
}
}
}
if (sec != null) {
if (logger.isDebugEnabled()) {
logger.debug("SQL error codes for '" + dbName + "' found");
}
return sec;
}
// Could not find the database among the defined ones.
if (logger.isDebugEnabled()) {
logger.debug("SQL error codes for '" + dbName + "' not found");
}
return new SQLErrorCodes();
}
/**
* Return {@link SQLErrorCodes} for the given {@link DataSource},
* evaluating "databaseProductName" from the
* {@link java.sql.DatabaseMetaData}, or an empty error codes
* instance if no <code>SQLErrorCodes</code> were found.
* @param dataSource the <code>DataSource</code> identifying the database
* @return the corresponding <code>SQLErrorCodes</code> object
* @see java.sql.DatabaseMetaData#getDatabaseProductName()
*/
public SQLErrorCodes getErrorCodes(DataSource dataSource) {
Assert.notNull(dataSource, "DataSource must not be null");
if (logger.isDebugEnabled()) {
logger.debug("Looking up default SQLErrorCodes for DataSource [" + dataSource + "]");
}
synchronized (this.dataSourceCache) {
// Let's avoid looking up database product info if we can.
SQLErrorCodes sec = (SQLErrorCodes) this.dataSourceCache.get(dataSource);
if (sec != null) {
if (logger.isDebugEnabled()) {
logger.debug("SQLErrorCodes found in cache for DataSource [" +
dataSource.getClass().getName() + '@' + Integer.toHexString(dataSource.hashCode()) + "]");
}
return sec;
}
// We could not find it - got to look it up.
try {
String dbName = (String)
JdbcUtils.extractDatabaseMetaData(dataSource, "getDatabaseProductName");
if (dbName != null) {
if (logger.isDebugEnabled()) {
logger.debug("Database product name cached for DataSource [" +
dataSource.getClass().getName() + '@' + Integer.toHexString(dataSource.hashCode()) +
"]: name is '" + dbName + "'");
}
sec = getErrorCodes(dbName);
this.dataSourceCache.put(dataSource, sec);
return sec;
}
}
catch (MetaDataAccessException ex) {
logger.warn("Error while extracting database product name - falling back to empty error codes", ex);
}
}
// Fallback is to return an empty SQLErrorCodes instance.
return new SQLErrorCodes();
}
/**
* Associate the specified database name with the given {@link DataSource}.
* @param dataSource the <code>DataSource</code> identifying the database
* @param dbName the corresponding database name as stated in the error codes
* definition file (must not be <code>null</code>)
* @return the corresponding <code>SQLErrorCodes</code> object
*/
public SQLErrorCodes registerDatabase(DataSource dataSource, String dbName) {
synchronized (this.dataSourceCache) {
SQLErrorCodes sec = getErrorCodes(dbName);
this.dataSourceCache.put(dataSource, sec);
return sec;
}
}
}