package org.codehaus.plexus.classworlds.strategy;
   
   import java.net.URL;
   import java.util.Collection;
   import java.util.Collections;
   import java.util.Enumeration;
   import java.util.LinkedHashSet;
   
   import org.codehaus.plexus.classworlds.UrlUtils;
  import org.codehaus.plexus.classworlds.realm.ClassRealm;
  
  /*
   * Copyright 2001-2006 Codehaus 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.
   */
  
  /**
   * @author Jason van Zyl
   */
  public abstract class AbstractStrategy implements Strategy {
  
      protected ClassRealm realm;
  
      public AbstractStrategy(ClassRealm realm) {
          this.realm = realm;
      }
  
      protected String getNormalizedResource(String name) {
          return UrlUtils.normalizeUrlPath(name);
      }
  
      protected Enumeration<URL> combineResources(Enumeration<URL> en1, Enumeration<URL> en2, Enumeration<URL> en3) {
          Collection<URL> urls = new LinkedHashSet<>();
  
          addAll(urls, en1);
          addAll(urls, en2);
          addAll(urls, en3);
  
          return Collections.enumeration(urls);
      }
  
      private void addAll(Collection<URL> target, Enumeration<URL> en) {
          if (en != null) {
              while (en.hasMoreElements()) {
                  target.add(en.nextElement());
              }
          }
      }
  
      public ClassRealm getRealm() {
          return realm;
      }
  }