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* distributed with this work for additional information *
* regarding copyright ownership. The ASF licenses this file *
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* "License"); you may not use this file except in compliance *
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* *
* http://www.apache.org/licenses/LICENSE-2.0 *
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* Unless required by applicable law or agreed to in writing, *
* software distributed under the License is distributed on an *
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package org.apache.james.util;
import org.apache.oro.text.perl.MalformedPerl5PatternException;
import org.apache.oro.text.perl.Perl5Util;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.NodeList;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.File;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/**
* Provides a set of SQL String resources (eg SQL Strings)
* to use for a database connection.
* This class allows SQL strings to be customised to particular
* database products, by detecting product information from the
* jdbc DatabaseMetaData object.
*
*/
public class SqlResources
{
/**
* A map of statement types to SQL statements
*/
private Map m_sql = new HashMap();
/**
* A map of engine specific options
*/
private Map m_dbOptions = new HashMap();
/**
* A set of all used String values
*/
static private Map stringTable = java.util.Collections.synchronizedMap(new HashMap());
/**
* A Perl5 regexp matching helper class
*/
private Perl5Util m_perl5Util = new Perl5Util();
/**
* Configures a DbResources object to provide SQL statements from a file.
*
* SQL statements returned may be specific to the particular type
* and version of the connected database, as well as the database driver.
*
* Parameters encoded as $(parameter} in the input file are
* replace by values from the parameters Map, if the named parameter exists.
* Parameter values may also be specified in the resourceSection element.
*
* @param sqlFile the input file containing the string definitions
* @param sqlDefsSection
* the xml element containing the strings to be used
* @param conn the Jdbc DatabaseMetaData, taken from a database connection
* @param configParameters a map of parameters (name-value string pairs) which are
* replaced where found in the input strings
*/
public void init(File sqlFile, String sqlDefsSection,
Connection conn, Map configParameters)
throws Exception
{
// Parse the sqlFile as an XML document.
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document sqlDoc = builder.parse(sqlFile);
// First process the database matcher, to determine the
// sql statements to use.
Element dbMatcherElement =
(Element)(sqlDoc.getElementsByTagName("dbMatchers").item(0));
String dbProduct = null;
if ( dbMatcherElement != null ) {
dbProduct = matchDbConnection(conn, dbMatcherElement);
m_perl5Util = null; // release the PERL matcher!
}
// Now get the options valid for the database product used.
Element dbOptionsElement =
(Element)(sqlDoc.getElementsByTagName("dbOptions").item(0));
if ( dbOptionsElement != null ) {
// First populate the map with default values
populateDbOptions("", dbOptionsElement, m_dbOptions);
// Now update the map with specific product values
if ( dbProduct != null ) {
populateDbOptions(dbProduct, dbOptionsElement, m_dbOptions);
}
}
// Now get the section defining sql for the repository required.
NodeList sections = sqlDoc.getElementsByTagName("sqlDefs");
int sectionsCount = sections.getLength();
Element sectionElement = null;
boolean found = false;
for (int i = 0; i < sectionsCount; i++ ) {
sectionElement = (Element)(sections.item(i));
String sectionName = sectionElement.getAttribute("name");
if ( sectionName != null && sectionName.equals(sqlDefsSection) ) {
found = true;
break;
}
}
if ( !found ) {
StringBuffer exceptionBuffer =
new StringBuffer(64)
.append("Error loading sql definition file. ")
.append("The element named \'")
.append(sqlDefsSection)
.append("\' does not exist.");
throw new RuntimeException(exceptionBuffer.toString());
}
// Get parameters defined within the file as defaults,
// and use supplied parameters as overrides.
Map parameters = new HashMap();
// First read from the <params> element, if it exists.
Element parametersElement =
(Element)(sectionElement.getElementsByTagName("parameters").item(0));
if ( parametersElement != null ) {
NamedNodeMap params = parametersElement.getAttributes();
int paramCount = params.getLength();
for (int i = 0; i < paramCount; i++ ) {
Attr param = (Attr)params.item(i);
String paramName = param.getName();
String paramValue = param.getValue();
parameters.put(paramName, paramValue);
}
}
// Then copy in the parameters supplied with the call.
parameters.putAll(configParameters);
// 2 maps - one for storing default statements,
// the other for statements with a "db" attribute matching this
// connection.
Map defaultSqlStatements = new HashMap();
Map dbProductSqlStatements = new HashMap();
// Process each sql statement, replacing string parameters,
// and adding to the appropriate map..
NodeList sqlDefs = sectionElement.getElementsByTagName("sql");
int sqlCount = sqlDefs.getLength();
for ( int i = 0; i < sqlCount; i++ ) {
// See if this needs to be processed (is default or product specific)
Element sqlElement = (Element)(sqlDefs.item(i));
String sqlDb = sqlElement.getAttribute("db");
Map sqlMap;
if ( sqlDb.equals("")) {
// default
sqlMap = defaultSqlStatements;
}
else if (sqlDb.equals(dbProduct) ) {
// Specific to this product
sqlMap = dbProductSqlStatements;
}
else {
// for a different product
continue;
}
// Get the key and value for this SQL statement.
String sqlKey = sqlElement.getAttribute("name");
if ( sqlKey == null ) {
// ignore statements without a "name" attribute.
continue;
}
String sqlString = sqlElement.getFirstChild().getNodeValue();
// Do parameter replacements for this sql string.
Iterator paramNames = parameters.keySet().iterator();
while ( paramNames.hasNext() ) {
String paramName = (String)paramNames.next();
String paramValue = (String)parameters.get(paramName);
StringBuffer replaceBuffer =
new StringBuffer(64)
.append("${")
.append(paramName)
.append("}");
sqlString = substituteSubString(sqlString, replaceBuffer.toString(), paramValue);
}
// See if we already have registered a string of this value
String shared = (String) stringTable.get(sqlString);
// If not, register it -- we will use it next time
if (shared == null) {
stringTable.put(sqlString, sqlString);
} else {
sqlString = shared;
}
// Add to the sqlMap - either the "default" or the "product" map
sqlMap.put(sqlKey, sqlString);
}
// Copy in default strings, then overwrite product-specific ones.
m_sql.putAll(defaultSqlStatements);
m_sql.putAll(dbProductSqlStatements);
}
/**
* Compares the DatabaseProductName value for a jdbc Connection
* against a set of regular expressions defined in XML.
* The first successful match defines the name of the database product
* connected to. This value is then used to choose the specific SQL
* expressions to use.
*
* @param conn the JDBC connection being tested
* @param dbMatchersElement the XML element containing the database type information
*
* @return the type of database to which James is connected
*
*/
private String matchDbConnection(Connection conn,
Element dbMatchersElement)
throws MalformedPerl5PatternException, SQLException
{
String dbProductName = conn.getMetaData().getDatabaseProductName();
NodeList dbMatchers =
dbMatchersElement.getElementsByTagName("dbMatcher");
for ( int i = 0; i < dbMatchers.getLength(); i++ ) {
// Get the values for this matcher element.
Element dbMatcher = (Element)dbMatchers.item(i);
String dbMatchName = dbMatcher.getAttribute("db");
StringBuffer dbProductPatternBuffer =
new StringBuffer(64)
.append("/")
.append(dbMatcher.getAttribute("databaseProductName"))
.append("/i");
// If the connection databaseProcuctName matches the pattern,
// use the match name from this matcher.
if ( m_perl5Util.match(dbProductPatternBuffer.toString(), dbProductName) ) {
return dbMatchName;
}
}
return null;
}
/**
* Gets all the name/value pair db option couples related to the dbProduct,
* and put them into the dbOptionsMap.
*
* @param dbProduct the db product used
* @param dbOptionsElement the XML element containing the options
* @param dbOptionsMap the <CODE>Map</CODE> to populate
*
*/
private void populateDbOptions(String dbProduct, Element dbOptionsElement, Map dbOptionsMap)
{
NodeList dbOptions =
dbOptionsElement.getElementsByTagName("dbOption");
for ( int i = 0; i < dbOptions.getLength(); i++ ) {
// Get the values for this option element.
Element dbOption = (Element)dbOptions.item(i);
// Check is this element is pertinent to the dbProduct
// Notice that a missing attribute returns "", good for defaults
if (!dbProduct.equalsIgnoreCase(dbOption.getAttribute("db"))) {
continue;
}
// Put into the map
dbOptionsMap.put(dbOption.getAttribute("name"), dbOption.getAttribute("value"));
}
}
/**
* Replace substrings of one string with another string and return altered string.
* @param input input string
* @param find the string to replace
* @param replace the string to replace with
* @return the substituted string
*/
private String substituteSubString( String input,
String find,
String replace )
{
int find_length = find.length();
int replace_length = replace.length();
StringBuffer output = new StringBuffer(input);
int index = input.indexOf(find);
int outputOffset = 0;
while ( index > -1 ) {
output.replace(index + outputOffset, index + outputOffset + find_length, replace);
outputOffset = outputOffset + (replace_length - find_length);
index = input.indexOf(find, index + find_length);
}
String result = output.toString();
return result;
}
/**
* Returns a named SQL string for the specified connection,
* replacing parameters with the values set.
*
* @param name the name of the SQL resource required.
* @return the requested resource
*/
public String getSqlString(String name)
{
return (String)m_sql.get(name);
}
/**
* Returns a named SQL string for the specified connection,
* replacing parameters with the values set.
*
* @param name the name of the SQL resource required.
* @param required true if the resource is required
* @return the requested resource
* @throws ConfigurationException
* if a required resource cannot be found.
*/
public String getSqlString(String name, boolean required)
{
String sql = getSqlString(name);
if (sql == null && required) {
StringBuffer exceptionBuffer =
new StringBuffer(64)
.append("Required SQL resource: '")
.append(name)
.append("' was not found.");
throw new RuntimeException(exceptionBuffer.toString());
}
return sql;
}
/**
* Returns the dbOption string value set for the specified dbOption name.
*
* @param name the name of the dbOption required.
* @return the requested dbOption value
*/
public String getDbOption(String name)
{
return (String)m_dbOptions.get(name);
}
}
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