/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed 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.commons.net.ftp.parser;
import org.apache.commons.net.ftp.FTPFileEntryParserImpl;
import org.apache.oro.text.regex.MalformedPatternException;
import org.apache.oro.text.regex.MatchResult;
import org.apache.oro.text.regex.Pattern;
import org.apache.oro.text.regex.PatternMatcher;
import org.apache.oro.text.regex.Perl5Compiler;
import org.apache.oro.text.regex.Perl5Matcher;
/**
* This abstract class implements both the older FTPFileListParser and
* newer FTPFileEntryParser interfaces with default functionality.
* All the classes in the parser subpackage inherit from this.
*
* This is the base for all regular based FTPFileEntryParser
*
* @author Steve Cohen <scohen@apache.org>
*/
public abstract class RegexFTPFileEntryParserImpl extends FTPFileEntryParserImpl
{
/**
* internal pattern the matcher tries to match, representing a file
* entry
*/
private Pattern pattern = null;
/**
* internal match result used by the parser
*/
private MatchResult result = null;
/**
* Internal PatternMatcher object used by the parser. It has protected
* scope in case subclasses want to make use of it for their own purposes.
*/
protected PatternMatcher _matcher_ = null;
/**
* The constructor for a RegexFTPFileEntryParserImpl object.
*
* @param regex The regular expression with which this object is
* initialized.
*
* @exception IllegalArgumentException
* Thrown if the regular expression is unparseable. Should not be seen in
* normal conditions. It it is seen, this is a sign that a subclass has
* been created with a bad regular expression. Since the parser must be
* created before use, this means that any bad parser subclasses created
* from this will bomb very quickly, leading to easy detection.
*/
public RegexFTPFileEntryParserImpl(String regex)
{
super();
try
{
_matcher_ = new Perl5Matcher();
pattern = new Perl5Compiler().compile(regex);
}
catch (MalformedPatternException e)
{
throw new IllegalArgumentException (
"Unparseable regex supplied: " + regex);
}
}
/**
* Convenience method delegates to the internal MatchResult's matches()
* method.
*
* @param s the String to be matched
* @return true if s matches this object's regular expression.
*/
public boolean matches(String s)
{
this.result = null;
if (_matcher_.matches(s.trim(), this.pattern))
{
this.result = _matcher_.getMatch();
}
return null != this.result;
}
/**
* Convenience method delegates to the internal MatchResult's groups()
* method.
*
* @return the number of groups() in the internal MatchResult.
*/
public int getGroupCnt()
{
if (this.result == null)
{
return 0;
}
return this.result.groups();
}
/**
* Convenience method delegates to the internal MatchResult's group()
* method.
*
* @param matchnum match group number to be retrieved
*
* @return the content of the <code>matchnum'th<code> group of the internal
* match or null if this method is called without a match having
* been made.
*/
public String group(int matchnum)
{
if (this.result == null)
{
return null;
}
return this.result.group(matchnum);
}
/**
* For debugging purposes - returns a string shows each match group by
* number.
*
* @return a string shows each match group by number.
*/
public String getGroupsAsString()
{
StringBuffer b = new StringBuffer();
for (int i = 1; i <= this.result.groups(); i++)
{
b.append(i).append(") ").append(this.result.group(i))
.append(System.getProperty("line.separator"));
}
return b.toString();
}
}
/* Emacs configuration
* Local variables: **
* mode: java **
* c-basic-offset: 4 **
* indent-tabs-mode: nil **
* End: **
*/