Commons Collections example source code file (UnmodifiableBoundedCollection.java)

This example Commons Collections source code file (UnmodifiableBoundedCollection.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Collections tags/keywords

abstractcollectiondecorator, abstractserializablecollectiondecorator, boundedcollection, boundedcollection, illegalargumentexception, iterator, synchronizedcollection, the, the, unmodifiableboundedcollection, unmodifiableboundedcollection, unsupportedoperationexception, unsupportedoperationexception, util

The Commons Collections UnmodifiableBoundedCollection.java source code

/*
 *  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;

/**
 * <code>UnmodifiableBoundedCollection decorates another 
 * <code>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.
 *
 * @since Commons Collections 3.0
 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
 * 
 * @author Stephen Colebourne
 */
public final class UnmodifiableBoundedCollection
        extends AbstractSerializableCollectionDecorator
        implements BoundedCollection {

    /** Serialization version */
    private static final long serialVersionUID = -7112672385450340330L;

    /**
     * Factory method to create an unmodifiable bounded collection.
     * 
     * @param coll  the <code>BoundedCollection to decorate, must not be null
     * @return a new unmodifiable bounded collection
     * @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 to decorate, must not be null
     * @return a new unmodifiable bounded collection
     * @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();
    }

}