org.apache.james.ai.classic.SqlResources Maven / Gradle / Ivy
/****************************************************************
* Licensed to the Apache Software Foundation (ASF) under one *
* or more contributor license agreements. See the NOTICE file *
* distributed with this work for additional information *
* regarding copyright ownership. The ASF licenses this file *
* to you 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.apache.james.ai.classic;
import java.io.File;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Pattern;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
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;
/**
* 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.
*
*/
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());
/**
*
* 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);
init(sqlDoc, sqlDefsSection, conn, configParameters);
}
/**
*
* Configures a DbResources object to provide SQL statements from an
* InputStream.
*
*
* 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 input
* the input stream containing the xml
* @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(InputStream input, String sqlDefsSection, Connection conn, Map configParameters) throws Exception {
// Parse the InputStream as an XML document.
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document sqlDoc = builder.parse(input);
init(sqlDoc, sqlDefsSection, conn, configParameters);
}
/**
* Configures a SqlResources object from an xml document.
*
* @param sqlDoc
* @param sqlDefsSection
* @param conn
* @param configParameters
* @throws SQLException
*/
protected void init(Document sqlDoc, String sqlDefsSection, Connection conn, Map configParameters) throws SQLException {
// 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);
}
// 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) {
StringBuilder exceptionBuffer = new StringBuilder(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 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.
StringBuilder replaceBuffer = new StringBuilder(64);
for (Map.Entry entry : parameters.entrySet()) {
replaceBuffer.setLength(0);
replaceBuffer.append("${").append(entry.getKey()).append("}");
sqlString = substituteSubString(sqlString, replaceBuffer.toString(), entry.getValue());
}
// See if we already have registered a string of this value
String shared = 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 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");
Pattern dbProductPattern = Pattern.compile(dbMatcher.getAttribute("databaseProductName"), Pattern.CASE_INSENSITIVE);
// If the connection databaseProcuctName matches the pattern,
// use the match name from this matcher.
if (dbProductPattern.matcher(dbProductName).find()) {
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 Map 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();
StringBuilder output = new StringBuilder(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 m_sql.get(name);
}
/**
* Returns a named SQL string for the specified connection, replacing
* parameters with the values set.
*
* @throws RuntimeException
* if a required resource cannot be found.
*
* @param name
* the name of the SQL resource required.
* @param required
* true if the resource is required
* @return the requested resource
*/
public String getSqlString(String name, boolean required) {
String sql = getSqlString(name);
if (sql == null && required) {
StringBuilder exceptionBuffer = new StringBuilder(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 m_dbOptions.get(name);
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy