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JDBC Driver for the Firebird RDBMS
/*
* Firebird Open Source JavaEE Connector - JDBC Driver
*
* Distributable under LGPL license.
* You may obtain a copy of the License at http://www.gnu.org/copyleft/lgpl.html
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* LGPL License for more details.
*
* This file was created by members of the firebird development team.
* All individual contributions remain the Copyright (C) of those
* individuals. Contributors to this file are either listed here or
* can be obtained from a source control history command.
*
* All rights reserved.
*/
package org.firebirdsql.jdbc;
import java.sql.SQLException;
import java.text.BreakIterator;
import java.util.regex.Pattern;
/**
* The class FBEscapedParser parses the SQL
* and converts escaped syntax to native form.
*
* @author Roman Rokytskyy
* @version 1.0
*/
public class FBEscapedParser {
public static final int USE_BUILT_IN = 0;
public static final int USE_STANDARD_UDF = 1;
/*
* Currently we have three states, normal when we simply copy characters
* from source to destination, escape state, when we extract the escaped
* syntax and literal, when we do copy characters from source to
* destination but we cannot enter the escape state.
*
* Currently these states seems to be exclusive, but later meanings may be
* extended, so we use the bit scale to map the state.
*/
protected static final int UNDEFINED_STATE = 0;
protected static final int NORMAL_STATE = 1;
protected static final int LITERAL_STATE = 2;
protected static final int ESCAPE_STATE = 4;
/*
Stored procedure calls support both following syntax:
{call procedure_name[(arg1, arg2, ...)]}
or
{?= call procedure_name[(arg1, arg2, ...)]}
*/
public static final String ESCAPE_CALL_KEYWORD = "call";
public static final String ESCAPE_CALL_KEYWORD3 = "?";
public static final String ESCAPE_DATE_KEYWORD = "d";
public static final String ESCAPE_TIME_KEYWORD = "t";
public static final String ESCAPE_TIMESTAMP_KEYWORD = "ts";
public static final String ESCAPE_FUNCTION_KEYWORD = "fn";
public static final String ESCAPE_ESCAPE_KEYWORD = "escape";
public static final String ESCAPE_OUTERJOIN_KEYWORS = "oj";
/**
* Regular expression to check for existence of JDBC escapes, is used to
* stop processing the entire SQL statement if it does not contain any of
* the substrings.
*/
private static final Pattern CHECK_ESCAPE_PATTERN = Pattern.compile(
"\\{(?:(?:\\?\\s*=\\s*)?call|d|ts?|escape|fn|oj)\\s",
Pattern.CASE_INSENSITIVE);
private int state = NORMAL_STATE;
private int lastState = NORMAL_STATE;
private int nestedEscaped = 0;
private int mode;
public FBEscapedParser(int mode) {
this.mode = mode;
}
/**
* Returns the current state.
*/
protected int getLastState() {
return lastState;
}
/**
* Returns the current state.
*/
protected int getState() {
return state;
}
/**
* Sets the current state.
* @param state to enter.
* @throws java.lang.IllegalStateException if the system cannot enter the desired state.
*/
protected void setState(int state) throws IllegalStateException {
int tempState = getLastState();
lastState = getState();
switch (state) {
case NORMAL_STATE:
case LITERAL_STATE:
case ESCAPE_STATE:
this.state = state;
break;
default:
lastState = tempState;
throw new IllegalStateException("State " + state + " is unknown.");
}
}
/**
* Returns if the system is in state state.
* @param state we're testing
* @return true if the system is in state state.
*/
protected boolean isInState(int state) {
return getState() == state;
}
/**
* Returns if the system was in state state.
* @param state we're testing
* @return true if the system was in state state.
*/
protected boolean wasInState(int state) {
return getLastState() == state;
}
/**
* Test the character to be the state switching character and switches
* the state if necessary.
* @param testChar character to test
*/
protected void switchState(char testChar) {
switch (testChar) {
case '\'':
if (isInState(NORMAL_STATE))
setState(LITERAL_STATE);
else if (isInState(LITERAL_STATE))
setState(NORMAL_STATE);
break;
case '{':
if (isInState(NORMAL_STATE))
setState(ESCAPE_STATE);
nestedEscaped++;
break;
case '}':
if (isInState(ESCAPE_STATE))
nestedEscaped--;
if (nestedEscaped == 0)
setState(NORMAL_STATE);
break;
}
}
/**
* Check if the target SQL contains at least one of the escaped syntax
* commands. This method performs a simple regex match, so it may
* report that SQL contains escaped syntax when the "{" is
* followed by the escaped syntax command in regular string constants that
* are passed as parameters. In this case {@link #parse(String)} will
* perform complete SQL parsing.
*
* @param sql to test
* @return true if the sql is suspected to contain
* escaped syntax.
*/
protected boolean checkForEscapes(String sql) {
return CHECK_ESCAPE_PATTERN.matcher(sql).find();
}
/**
* Converts escaped parts in the passed SQL to native representation.
* @param sql to parse
* @return native form of the sql.
*/
public String parse(String sql) throws SQLException {
lastState = NORMAL_STATE;
state = NORMAL_STATE;
nestedEscaped = 0;
if (!checkForEscapes(sql)) {
return sql;
}
try {
final StringBuilder buffer = new StringBuilder();
final StringBuilder escape = new StringBuilder();
for (int i = 0; i < sql.length(); i++) {
char currentChar = sql.charAt(i);
switchState(currentChar);
if (isInState(NORMAL_STATE) &&
(wasInState(NORMAL_STATE) || wasInState(LITERAL_STATE))) {
buffer.append(currentChar);
} else if (isInState(NORMAL_STATE) && wasInState(ESCAPE_STATE)) {
// escape now is in form "{...." without trailing '}'...
buffer.append(escapeToNative(escape.substring(1, escape.length())));
escape.setLength(0);
setState(NORMAL_STATE);
} else if (isInState(ESCAPE_STATE)) {
escape.append(currentChar);
} else if (isInState(LITERAL_STATE)) {
buffer.append(currentChar);
}
}
return buffer.toString();
} catch (IllegalStateException e) {
FBSQLParseException parseException =
new FBSQLParseException("Parser reached an invalid state: " + e.getMessage());
parseException.initCause(e);
throw parseException;
}
}
protected void processEscaped(String escaped, StringBuilder keyword, StringBuilder payload) {
keyword.setLength(0);
payload.setLength(0);
/*
* Extract the keyword from the escaped syntax.
*/
BreakIterator iterator = BreakIterator.getWordInstance();
iterator.setText(escaped);
int keyStart = iterator.first();
int keyEnd = iterator.next();
keyword.append(escaped.substring(keyStart, keyEnd));
payload.append(escaped.substring(keyEnd, escaped.length()));
}
/**
* This method checks the passed parameter to conform the escaped syntax,
* checks for the unknown keywords and re-formats result according to the
* Firebird SQL syntax.
* @param escaped the part of escaped SQL between the '{' and '}'.
* @return the native representation of the SQL code.
*/
protected String escapeToNative(String escaped) throws SQLException {
final StringBuilder keyword = new StringBuilder();
final StringBuilder payload = new StringBuilder();
processEscaped(escaped, keyword, payload);
/*
* Handle keywords.
*/
if (keyword.toString().equalsIgnoreCase(ESCAPE_CALL_KEYWORD)) {
return convertProcedureCall("{" + keyword + ' ' + payload + '}');
} else if (keyword.toString().equalsIgnoreCase(ESCAPE_CALL_KEYWORD3)) {
return convertProcedureCall("{" + ESCAPE_CALL_KEYWORD3 + payload + '}');
} else if (keyword.toString().equalsIgnoreCase(ESCAPE_DATE_KEYWORD)) {
return toDateString(payload.toString().trim());
} else if (keyword.toString().equalsIgnoreCase(ESCAPE_ESCAPE_KEYWORD)) {
return convertEscapeString(payload.toString().trim());
} else if (keyword.toString().equalsIgnoreCase(ESCAPE_FUNCTION_KEYWORD)) {
return convertEscapedFunction(payload.toString().trim());
} else if (keyword.toString().equalsIgnoreCase(ESCAPE_OUTERJOIN_KEYWORS)) {
return convertOuterJoin(payload.toString().trim());
} else if (keyword.toString().equalsIgnoreCase(ESCAPE_TIME_KEYWORD)) {
return toTimeString(payload.toString().trim());
} else if (keyword.toString().equalsIgnoreCase(ESCAPE_TIMESTAMP_KEYWORD)) {
return toTimestampString(payload.toString().trim());
} else {
throw new FBSQLParseException("Unknown keyword " + keyword + " for escaped syntax.");
}
}
/**
* This method converts the 'yyyy-mm-dd' date format into the
* Firebird understandable format.
* @param dateStr the date in the 'yyyy-mm-dd' format.
* @return Firebird understandable date format.
*/
protected String toDateString(String dateStr) throws FBSQLParseException {
/*
* We assume that Firebird can handle the 'yyyy-mm-dd' date format.
*/
return dateStr;
}
/**
* This method converts the 'hh:mm:ss' time format into the
* Firebird understandable format.
* @param timeStr the date in the 'hh:mm:ss' format.
* @return Firebird understandable date format.
*/
protected String toTimeString(String timeStr) throws FBSQLParseException {
/*
* We assume that Firebird can handle the 'hh:mm:ss' date format.
*/
return timeStr;
}
/**
* This method converts the 'yyyy-mm-dd hh:mm:ss' timestamp format into the
* Firebird understandable format.
* @param timestampStr the date in the 'yyyy-mm-dd hh:mm:ss' format.
* @return Firebird understandable date format.
*/
protected String toTimestampString(String timestampStr) throws FBSQLParseException {
/*
* We assume that Firebird can handle the 'dd.mm.yyyy hh:mm:ss' date format.
*/
return timestampStr;
}
/**
* This methods converts the escaped procedure call syntax into the
* native procedure call.
* @param procedureCall part of {call proc_name(...)} without curly braces and "call" word.
* @return native procedure call.
*/
protected String convertProcedureCall(String procedureCall) throws SQLException {
FBEscapedCallParser tempParser = new FBEscapedCallParser(mode);
FBProcedureCall call = tempParser.parseCall(procedureCall);
call.checkParameters();
return call.getSQL(false);
}
/**
* This method converts the escaped outer join call syntax into the
* native outer join. Actually, we do not change anything here, since
* Firebird's syntax is the same.
*/
protected String convertOuterJoin(String outerJoin) throws FBSQLParseException {
return outerJoin;
}
/**
* Convert the "{escape '...'}" call into the corresponding
* escape clause for Firebird.
*
* @param escapeString escape string to convert
*
* @return converted code.
*/
protected String convertEscapeString(String escapeString) {
return "ESCAPE " + escapeString;
}
/**
* This method converts escaped function to a server function call. Actually
* we do not change anything here, we hope that all UDF are defined.
*
* @param escapedFunction escaped function call
* @return server-side function call.
*
* @throws FBSQLParseException if something was wrong.
*/
protected String convertEscapedFunction(String escapedFunction)
throws FBSQLParseException {
String templateResult =
FBEscapedFunctionHelper.convertTemplate(escapedFunction, mode);
if (templateResult != null)
return templateResult;
else
return escapedFunction;
}
public static boolean supportsStoredProcedures() {
return true;
}
public static boolean supportsLikeEscapeClause() {
return false;
}
}