/**
* Redistribution and use of this software and associated documentation
* ("Software"), with or without modification, are permitted provided
* that the following conditions are met:
*
* 1. Redistributions of source code must retain copyright
* statements and notices. Redistributions must also contain a
* copy of this document.
*
* 2. Redistributions in binary form must reproduce the
* above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* 3. The name "Exolab" must not be used to endorse or promote
* products derived from this Software without prior written
* permission of Exoffice Technologies. For written permission,
* please contact info@exolab.org.
*
* 4. Products derived from this Software may not be called "Exolab"
* nor may "Exolab" appear in their names without prior written
* permission of Exoffice Technologies. Exolab is a registered
* trademark of Exoffice Technologies.
*
* 5. Due credit should be given to the Exolab Project
* (http://www.exolab.org/).
*
* THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
* NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Copyright 2000-2001,2003 (C) Exoffice Technologies Inc. All Rights Reserved.
*/
package org.exolab.jms.selector;
import org.apache.oro.text.regex.MalformedPatternException;
import org.apache.oro.text.regex.Pattern;
import org.apache.oro.text.regex.Perl5Compiler;
/**
* Regular expression factory. This creates a regular expression for a given
* SQL92 pattern and escape character.
*
* @version $Revision: 1.1 $ $Date: 2004/11/26 01:50:44 $
* @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a>
*/
final class RegexpFactory {
/**
* Private constructor
*/
private RegexpFactory() {
}
/**
* Converts the pattern and escape to an ORO <code>Pattern</code>
*
* @param pattern the pattern
* @param escape the escape character. May be null
* @return an ORO <code>Pattern</code> corresponding to
* <code>pattern</code> and <code>escape</code>
* @throws InvalidRegexpException if <code>pattern</code> or
* <code>escape</code> are invalid
*/
public static Pattern create(final String pattern, final Character escape)
throws InvalidRegexpException {
StringBuffer buff = new StringBuffer();
buff.append('^');
for (int i = 0; i < pattern.length(); ++i) {
boolean escaped = false;
char ch = pattern.charAt(i);
if (escape != null && ch == escape.charValue()) {
if (++i < pattern.length()) {
ch = pattern.charAt(i);
escaped = true;
} else {
throw new InvalidRegexpException(pattern);
}
}
switch (ch) {
case '_':
if (escaped) {
buff.append(ch);
} else {
buff.append('.');
}
break;
case '%':
if (escaped) {
buff.append(ch);
} else {
buff.append(".*");
}
break;
case '.':
case '[':
case ']':
case '\\':
case '+':
case '?':
case '{':
case '}':
case '$':
case '^':
case '|':
case '(':
case ')':
// the above are all special characters that need to be
// escaped.
buff.append('\\');
buff.append(ch);
break;
default:
buff.append(ch);
}
}
buff.append('$');
Pattern result = null;
try {
Perl5Compiler compiler = new Perl5Compiler();
result = compiler.compile(buff.toString());
} catch (MalformedPatternException exception) {
// coding error if this gets thrown here...
throw new InvalidRegexpException(pattern);
}
return result;
}
} //-- RegexpFactory