//
   //  ========================================================================
   //  Copyright (c) 1995-2015 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.util;
  
  import java.util.AbstractSet;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Set;
  import java.util.function.BiFunction;
  import java.util.regex.Pattern;
  
  
  /**
   * A Set of Regular expressions strings.
   * <p>
   * Provides the efficient {@link #matches(String)} method to check for a match against all the combined Regex's
   */
  public class RegexSet extends AbstractSet<String>
  {
      public static final BiFunction<RegexSet,String,Boolean> MATCHER=(rs,p)->{return rs.matches(p);};
      private final Set<String> _patterns=new HashSet<String>();
      private final Set<String> _unmodifiable=Collections.unmodifiableSet(_patterns);
      private Pattern _pattern;
      
      @Override
      public Iterator<String> iterator()
      {
          return _unmodifiable.iterator();
      }
  
      @Override
      public int size()
      {
          return _patterns.size();
      }
      
      @Override
      public boolean add(String pattern)
      {
          boolean added = _patterns.add(pattern);
          if (added)
              updatePattern();
          return added;
      }
      
      @Override
      public boolean remove(Object pattern)
      {
          boolean removed = _patterns.remove(pattern);
  
          if (removed)
              updatePattern();
          return removed;
      }
  
      @Override
      public boolean isEmpty()
      {
          return _patterns.isEmpty();
      }
  
      @Override
      public void clear()
      {
          _patterns.clear();
          _pattern=null;
      }
  
      private void updatePattern()
      {
          StringBuilder builder = new StringBuilder();
          builder.append("^(");
          for (String pattern: _patterns)
          {
              if (builder.length()>2)
                  builder.append('|');
              builder.append('(');
              builder.append(pattern);
              builder.append(')');
          }
          builder.append(")$");
          _pattern = Pattern.compile(builder.toString());   
     }
 
     public boolean matches(String s)
     {
         return _pattern!=null && _pattern.matcher(s).matches();
     }
 }