/* gnu.classpath.tools.doclets.PackageMatcher
   Copyright (C) 2004 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
 
GNU Classpath 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 GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */

package gnu.classpath.tools.doclets;

import java.util.Iterator;
import java.util.HashSet;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.sun.javadoc.PackageDoc;

/**
 *  Filters a set of packages according to a set of wildcards.
 */
public class PackageMatcher
{
   private Set patterns = new HashSet();
   
   /**
    *  Add a wildcard to be matched. Wildcards can contain asterisk
    *  characters which match zero or more characters.
    *
    *  @throw InvalidPackageWildcardException if the wildcard cannot
    *  match any valid package name.
    */
   public void addWildcard(String wildcard) 
      throws InvalidPackageWildcardException
   {
      final int STATE_ID_START = 0;
      final int STATE_ID = 1;

      int state = STATE_ID_START;

      char[] wildcardChars = wildcard.toCharArray();
      StringBuffer regexString = new StringBuffer();

      for (int i=0; i<wildcardChars.length; ++i) {
         char c = wildcardChars[i];
         switch (state) {
         case STATE_ID_START:
            if ('*' == c) {
               regexString.append(".*");
            }
            else if (Character.isJavaIdentifierStart(c)) {
               regexString.append(c);
            }
            else {
               throw new InvalidPackageWildcardException(wildcard);
            }
            state = STATE_ID;
            break;

         case STATE_ID:
            if ('.' == c) {
               regexString.append("\\.");
               state = STATE_ID_START;
            }
            else if ('*' == c) {
               regexString.append(".*");
            }
            else if (Character.isJavaIdentifierPart(c)) {
               regexString.append(c);
            }
            else {
               throw new InvalidPackageWildcardException(wildcard);
            }
         }
      }
      if (STATE_ID_START == state) {
         throw new InvalidPackageWildcardException(wildcard);
      }

      patterns.add(Pattern.compile(regexString.toString()));
   }

   /**
    *  Return a sorted, filtered set of packages. A package from the
    *  array given will be put into the output list if it matches one
    *  or more of the wildcards added to this PackageMatcher before.
    */
   public SortedSet filter(PackageDoc[] packageDocs)
   {
      SortedSet result = new TreeSet();
      for (int i=0; i<packageDocs.length; ++i) {
         if (match(packageDocs[i])) {
            result.add(packageDocs[i]);
         }
      }
      return result;
   }

   /**
    *  Return true when the given PackageDoc matches one or more of
    *  the wildcard added to this PackageMatcher before.
    */
   public boolean match(PackageDoc packageDoc)
   {
      Iterator it = patterns.iterator();
      while (it.hasNext()) {
         Pattern pattern = (Pattern)it.next();
         Matcher matcher = pattern.matcher(packageDoc.name());
         if (matcher.matches()) {
            break;
         }
      }
      return false;
   }
}