/*
    * 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
    *
    *      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.collections.collection;
  
  import java.util.Collection;
  import java.util.Iterator;
  
  import org.apache.commons.collections.BoundedCollection;
  import org.apache.commons.collections.iterators.UnmodifiableIterator;
  
  /**
   * {@link UnmodifiableBoundedCollection} decorates another
   * {@link BoundedCollection} to ensure it can't be altered.
   * <p>
   * If a BoundedCollection is first wrapped in some other collection decorator,
   * such as synchronized or predicated, the BoundedCollection methods are no
   * longer accessible.
   * The factory on this class will attempt to retrieve the bounded nature by
   * examining the package scope variables.
   * <p>
   * This class is Serializable from Commons Collections 3.1.
   * <p>
   * Attempts to modify it will result in an UnsupportedOperationException. 
   *
   * @since 3.0
   * @version $Id: UnmodifiableBoundedCollection.java 1429905 2013-01-07 17:15:14Z ggregory $
   */
  public final class UnmodifiableBoundedCollection<E> extends AbstractCollectionDecorator<E>
          implements BoundedCollection<E> {
  
      /** Serialization version */
      private static final long serialVersionUID = -7112672385450340330L;
  
      /**
       * Factory method to create an unmodifiable bounded collection.
       *
       * @param <E> the type of the elements in the collection
       * @param coll  the <code>BoundedCollection</code> to decorate, must not be null
       * @return a new unmodifiable bounded collection
       * @throws IllegalArgumentException if {@code coll} is {@code null}
       */
      public static <E> BoundedCollection<E> unmodifiableBoundedCollection(final BoundedCollection<E> coll) {
          return new UnmodifiableBoundedCollection<E>(coll);
      }
  
      /**
       * Factory method to create an unmodifiable bounded collection.
       * <p>
       * This method is capable of drilling down through up to 1000 other decorators
       * to find a suitable BoundedCollection.
       *
       * @param <E> the type of the elements in the collection
       * @param coll  the <code>BoundedCollection</code> to decorate, must not be null
       * @return a new unmodifiable bounded collection
       * @throws IllegalArgumentException if {@code coll} is {@code null}
       */
      @SuppressWarnings("unchecked")
      public static <E> BoundedCollection<E> unmodifiableBoundedCollection(Collection<? extends E> coll) {
          if (coll == null) {
              throw new IllegalArgumentException("The collection must not be null");
          }
  
          // handle decorators
          for (int i = 0; i < 1000; i++) {  // counter to prevent infinite looping
              if (coll instanceof BoundedCollection) {
                  break;  // normal loop exit
              }
              if (coll instanceof AbstractCollectionDecorator) {
                  coll = ((AbstractCollectionDecorator<E>) coll).collection;
              } else if (coll instanceof SynchronizedCollection) {
                  coll = ((SynchronizedCollection<E>) coll).collection;
              }
          }
  
          if (coll instanceof BoundedCollection == false) {
              throw new IllegalArgumentException("The collection is not a bounded collection");
          }
          return new UnmodifiableBoundedCollection<E>((BoundedCollection<E>) coll);
      }
  
      /**
       * Constructor that wraps (not copies).
       *
       * @param coll  the collection to decorate, must not be null
       * @throws IllegalArgumentException if coll is null
      */
     private UnmodifiableBoundedCollection(final BoundedCollection<E> coll) {
         super(coll);
     }
 
     //-----------------------------------------------------------------------
     @Override
     public Iterator<E> iterator() {
         return UnmodifiableIterator.unmodifiableIterator(decorated().iterator());
     }
 
     @Override
     public boolean add(final E object) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public boolean addAll(final Collection<? extends E> coll) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public void clear() {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public boolean remove(final Object object) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public boolean removeAll(final Collection<?> coll) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public boolean retainAll(final Collection<?> coll) {
         throw new UnsupportedOperationException();
     }
 
     //-----------------------------------------------------------------------
     public boolean isFull() {
         return decorated().isFull();
     }
 
     public int maxSize() {
         return decorated().maxSize();
     }
 
     @Override
     protected BoundedCollection<E> decorated() {
         return (BoundedCollection<E>) super.decorated();
     }
 }