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 *    any, must include the following acknowledgement:
 *       "This product includes software developed by the
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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;

/**
 * <code>UnmodifiableBoundedCollection</code> decorates another <code>BoundedCollection</code>
 * 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 nature is lost.
 * The factory on this class will attempt to retrieve the bounded nature by
 * examining the package scope variables.
 *
 * @since Commons Collections 3.0
 * @version $Revision: 1.5 $ $Date: 2004/01/14 21:43:18 $
 * 
 * @author Stephen Colebourne
 */
public final class UnmodifiableBoundedCollection extends AbstractCollectionDecorator implements BoundedCollection {
    
    /**
     * Factory method to create an unmodifiable bounded collection.
     * 
     * @param coll  the <code>BoundedCollection</code> to decorate, must not be null
     * @throws IllegalArgumentException if bag is null
     */
    public static BoundedCollection decorate(BoundedCollection coll) {
        return new UnmodifiableBoundedCollection(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 coll  the <code>BoundedCollection</code> to decorate, must not be null
     * @throws IllegalArgumentException if bag is null
     */
    public static BoundedCollection decorateUsing(Collection 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
            } else if (coll instanceof AbstractCollectionDecorator) {
                coll = ((AbstractCollectionDecorator) coll).collection;
            } else if (coll instanceof SynchronizedCollection) {
                coll = ((SynchronizedCollection) coll).collection;
            } else {
                break;  // normal loop exit
            }
        }
            
        if (coll instanceof BoundedCollection == false) {
            throw new IllegalArgumentException("The collection is not a bounded collection");
        }
        return new UnmodifiableBoundedCollection((BoundedCollection) coll);
    }    
    
    /**
     * Constructor that wraps (not copies).
     * 
     * @param coll  the collection to decorate, must not be null
     * @throws IllegalArgumentException if coll is null
     */
    private UnmodifiableBoundedCollection(BoundedCollection coll) {
        super(coll);
    }

    //-----------------------------------------------------------------------
    public Iterator iterator() {
        return UnmodifiableIterator.decorate(getCollection().iterator());
    }

    public boolean add(Object object) {
        throw new UnsupportedOperationException();
    }

    public boolean addAll(Collection coll) {
        throw new UnsupportedOperationException();
    }

    public void clear() {
        throw new UnsupportedOperationException();
    }

    public boolean remove(Object object) {
        throw new UnsupportedOperationException();
    }

    public boolean removeAll(Collection coll) {
        throw new UnsupportedOperationException();
    }

    public boolean retainAll(Collection coll) {
        throw new UnsupportedOperationException();
    }

    //-----------------------------------------------------------------------    
    public boolean isFull() {
        return ((BoundedCollection) collection).isFull();
    }

    public int maxSize() {
        return ((BoundedCollection) collection).maxSize();
    }
    
}
