/*
    * 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.primitives;
  
  /**
   * Abstract base class for {@link BooleanCollection}s.
   * <p/>
   * Read-only subclasses must override {@link #iterator} and {@link #size}.
   * Mutable subclasses should also override {@link #add} and {@link
   * BooleanIterator#remove BooleanIterator.remove}.  All other methods have
   * at least some base implementation derived from these.  Subclasses may
   * choose to override these methods to provide a more efficient implementation.
   * 
   * @since Commons Primitives 1.1
   * @version $Revision: 480460 $ $Date: 2006-11-29 03:14:21 -0500 (Wed, 29 Nov 2006) $
   */
  public abstract class AbstractBooleanCollection implements BooleanCollection {
      public abstract BooleanIterator iterator();
      public abstract int size();
            
      protected AbstractBooleanCollection() { }
                
      /** Unsupported in this base implementation. */
      public boolean add(boolean element) {
          throw new UnsupportedOperationException(
                  "add(boolean) is not supported.");
      }
  
      public boolean addAll(BooleanCollection c) {
          boolean modified = false;
          for(BooleanIterator iter = c.iterator(); iter.hasNext(); ) {
              modified  |= add(iter.next());
          }
          return modified;
      }
      
      public void clear() {
          for(BooleanIterator iter = iterator(); iter.hasNext();) {
              iter.next();
              iter.remove();
          }
      }        
  
      public boolean contains(boolean element) {
          for(BooleanIterator iter = iterator(); iter.hasNext();) {
              if(iter.next() == element) {
                  return true;
              }
          }
          return false;
      }
          
      public boolean containsAll(BooleanCollection c) {
          for(BooleanIterator iter = c.iterator(); iter.hasNext();) {
              if(!contains(iter.next())) {
                  return false;
              }
          }
          return true;
      }
      
      public boolean isEmpty() {
          return (0 == size());
      }
         
      public boolean removeElement(boolean element) {
          for(BooleanIterator iter = iterator(); iter.hasNext();) {
              if(iter.next() == element) {
                  iter.remove();
                  return true;
              }
          }
          return false;
      }        
      
      public boolean removeAll(BooleanCollection c) {
          boolean modified = false;
          for(BooleanIterator iter = c.iterator(); iter.hasNext(); ) {
              modified  |= removeElement(iter.next());
          }
          return modified;
      }       
      
      public boolean retainAll(BooleanCollection c) {
          boolean modified = false;
         for(BooleanIterator iter = iterator(); iter.hasNext();) {
             if(!c.contains(iter.next())) {
                 iter.remove();
                 modified = true;
             }
         }
         return modified;
     }
     
     public boolean[] toArray() {
         boolean[] array = new boolean[size()];
         int i = 0;
         for(BooleanIterator iter = iterator(); iter.hasNext();) {
             array[i] = iter.next();
             i++;
         }
         return array;
     }
         
     public boolean[] toArray(boolean[] a) {
         if(a.length < size()) {
             return toArray();
         } else {
             int i = 0;
             for(BooleanIterator iter = iterator(); iter.hasNext();) {
                 a[i] = iter.next();
                 i++;
             }
             return a;
         }            
     }
 }