/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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
    *
   *   https://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.bcel.verifier;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Set;
  import java.util.TreeSet;
  
  import javax.swing.ListModel;
  import javax.swing.event.ListDataEvent;
  import javax.swing.event.ListDataListener;
  
  import org.apache.commons.lang3.ArrayUtils;
  
  /**
   * This class implements an adapter; it implements both a Swing ListModel and a VerifierFactoryObserver.
   */
  public class VerifierFactoryListModel implements VerifierFactoryObserver, ListModel<String> {
  
      private final List<ListDataListener> listeners = new ArrayList<>();
      private final Set<String> cache = new TreeSet<>();
  
      /**
       * Constructs a VerifierFactoryListModel.
       */
      public VerifierFactoryListModel() {
          VerifierFactory.attach(this);
          update(null); // fill cache.
      }
  
      @Override
      public synchronized void addListDataListener(final ListDataListener l) {
          listeners.add(l);
      }
  
      @Override
      public synchronized String getElementAt(final int index) {
          return cache.toArray(ArrayUtils.EMPTY_STRING_ARRAY)[index];
      }
  
      @Override
      public synchronized int getSize() {
          return cache.size();
      }
  
      @Override
      public synchronized void removeListDataListener(final ListDataListener l) {
          listeners.remove(l);
      }
  
      @Override
      public synchronized void update(final String s) {
          final Verifier[] verifiers = VerifierFactory.getVerifiers();
          final int verifierLen = verifiers.length;
          cache.clear();
          for (final Verifier verifier : verifiers) {
              cache.add(verifier.getClassName());
          }
          for (final ListDataListener listener : listeners) {
              listener.contentsChanged(new ListDataEvent(this, ListDataEvent.CONTENTS_CHANGED, 0, verifierLen - 1));
          }
      }
  
  }