mailet/ai/src/main/java/org/apache/james/ai/classic/SqlResources.java - james-project - Git at Google

 /****************************************************************
  * 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.<br>
  * 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 final Map<String, String> sql = new HashMap<>();

     /** A map of engine specific options */
     private final Map<String, String> dbOptions = new HashMap<>();

     /** A set of all used String values */
     private static final Map<String, String> stringTable = java.util.Collections.synchronizedMap(new HashMap<>());

     /**
      * <p>
      * Configures a DbResources object to provide SQL statements from a file.
      * </p>
      * <p>
      * SQL statements returned may be specific to the particular type and
      * version of the connected database, as well as the database driver.
      * </p>
      * <p>
      * 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.
      * </p>
      *
      * @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<String, String> 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);
     }

     /**
      * <p>
      * Configures a DbResources object to provide SQL statements from an
      * InputStream.
      * </p>
      * <p>
      * SQL statements returned may be specific to the particular type and
      * version of the connected database, as well as the database driver.
      * </p>
      * <p>
      * 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.
      * </p>
      *
      * @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<String, String> 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<String, String> 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, dbOptions);
             // Now update the map with specific product values
             if (dbProduct != null) {
                 populateDbOptions(dbProduct, dbOptionsElement, 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<String, String> 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<String, String> defaultSqlStatements = new HashMap<>();
         Map<String, String> 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<String, String> 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<String, String> 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.
         sql.putAll(defaultSqlStatements);
         sql.putAll(dbProductSqlStatements);
     }

     /**
      * Compares the DatabaseProductName value for a jdbc Connection against a
      * set of regular expressions defined in XML.<br>
      * 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 <code>Map</code> to populate
      *
      */
     private void populateDbOptions(String dbProduct, Element dbOptionsElement, Map<String, String> 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 findLength = find.length();
         int replaceLength = replace.length();

         StringBuilder output = new StringBuilder(input);
         int index = input.indexOf(find);
         int outputOffset = 0;

         while (index > -1) {
             output.replace(index + outputOffset, index + outputOffset + findLength, replace);
             outputOffset = outputOffset + (replaceLength - findLength);

             index = input.indexOf(find, index + findLength);
         }

         return output.toString();
     }

     /**
      * 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 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 dbOptions.get(name);
     }

 }
	/****************************************************************
	* 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.<br>
	* 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 final Map<String, String> sql = new HashMap<>();

	/** A map of engine specific options */
	private final Map<String, String> dbOptions = new HashMap<>();

	/** A set of all used String values */
	private static final Map<String, String> stringTable = java.util.Collections.synchronizedMap(new HashMap<>());

	/**
	* <p>
	* Configures a DbResources object to provide SQL statements from a file.
	* </p>
	* <p>
	* SQL statements returned may be specific to the particular type and
	* version of the connected database, as well as the database driver.
	* </p>
	* <p>
	* 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.
	* </p>
	*
	* @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<String, String> 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);
	}

	/**
	* <p>
	* Configures a DbResources object to provide SQL statements from an
	* InputStream.
	* </p>
	* <p>
	* SQL statements returned may be specific to the particular type and
	* version of the connected database, as well as the database driver.
	* </p>
	* <p>
	* 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.
	* </p>
	*
	* @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<String, String> 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<String, String> 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, dbOptions);
	// Now update the map with specific product values
	if (dbProduct != null) {
	populateDbOptions(dbProduct, dbOptionsElement, 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<String, String> 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<String, String> defaultSqlStatements = new HashMap<>();
	Map<String, String> 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<String, String> 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<String, String> 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.
	sql.putAll(defaultSqlStatements);
	sql.putAll(dbProductSqlStatements);
	}

	/**
	* Compares the DatabaseProductName value for a jdbc Connection against a
	* set of regular expressions defined in XML.<br>
	* 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 <code>Map</code> to populate
	*
	*/
	private void populateDbOptions(String dbProduct, Element dbOptionsElement, Map<String, String> 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 findLength = find.length();
	int replaceLength = replace.length();

	StringBuilder output = new StringBuilder(input);
	int index = input.indexOf(find);
	int outputOffset = 0;

	while (index > -1) {
	output.replace(index + outputOffset, index + outputOffset + findLength, replace);
	outputOffset = outputOffset + (replaceLength - findLength);

	index = input.indexOf(find, index + findLength);
	}

	return output.toString();
	}

	/**
	* 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 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 dbOptions.get(name);
	}

	}