org.apache.commons.collections.collection.UnmodifiableBoundedCollection Maven / Gradle / Ivy
/*
* 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;
/**
* UnmodifiableBoundedCollection decorates another
* BoundedCollection to ensure it can't be altered.
*
* 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.
*
* This class is Serializable from Commons Collections 3.1.
*
* @since Commons Collections 3.0
* @version $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (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 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.
*
* This method is capable of drilling down through up to 1000 other decorators
* to find a suitable BoundedCollection.
*
* @param coll the 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();
}
}