org.apache.commons.collections.BagUtils Maven / Gradle / Ivy
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/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2002-2004 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "Apache"
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*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
*
* It is imperative that the user manually synchronize on the returned
* bag when iterating over it:
*
*
* Bag bag = BagUtils.synchronizedBag(new HashBag());
* ...
* synchronized(bag) {
* Iterator i = bag.iterator(); // Must be in synchronized block
* while (i.hasNext())
* foo(i.next());
* }
* }
*
*
* Failure to follow this advice may result in non-deterministic
* behavior.
*
* @param bag the bag to synchronize, must not be null
* @return a synchronized bag backed by that bag
* @throws IllegalArgumentException if the Bag is null
*/
public static Bag synchronizedBag(Bag bag) {
return SynchronizedBag.decorate(bag);
}
/**
* Returns an unmodifiable view of the given bag. Any modification
* attempts to the returned bag will raise an
* {@link UnsupportedOperationException}.
*
* @param bag the bag whose unmodifiable view is to be returned, must not be null
* @return an unmodifiable view of that bag
* @throws IllegalArgumentException if the Bag is null
*/
public static Bag unmodifiableBag(Bag bag) {
return UnmodifiableBag.decorate(bag);
}
/**
* Returns a predicated bag backed by the given bag. Only objects
* that pass the test in the given predicate can be added to the bag.
* It is important not to use the original bag after invoking this
* method, as it is a backdoor for adding unvalidated objects.
*
* @param bag the bag to predicate, must not be null
* @param predicate the predicate for the bag, must not be null
* @return a predicated bag backed by the given bag
* @throws IllegalArgumentException if the Bag or Predicate is null
*/
public static Bag predicatedBag(Bag bag, Predicate predicate) {
return PredicatedBag.decorate(bag, predicate);
}
/**
* Returns a typed bag backed by the given bag.
*
* Only objects of the specified type can be added to the bag.
*
* @param bag the bag to limit to a specific type, must not be null
* @param type the type of objects which may be added to the bag
* @return a typed bag backed by the specified bag
*/
public static Bag typedBag(Bag bag, Class type) {
return TypedBag.decorate(bag, type);
}
/**
* Returns a transformed bag backed by the given bag.
*
* Each object is passed through the transformer as it is added to the
* Bag. It is important not to use the original bag after invoking this
* method, as it is a backdoor for adding untransformed objects.
*
* @param bag the bag to predicate, must not be null
* @param transformer the transformer for the bag, must not be null
* @return a transformed bag backed by the given bag
* @throws IllegalArgumentException if the Bag or Transformer is null
*/
public static Bag transformedBag(Bag bag, Transformer transformer) {
return TransformedBag.decorate(bag, transformer);
}
//-----------------------------------------------------------------------
/**
* Returns a synchronized (thread-safe) sorted bag backed by the given
* sorted bag.
* In order to guarantee serial access, it is critical that all
* access to the backing bag is accomplished through the returned bag.
*
* It is imperative that the user manually synchronize on the returned
* bag when iterating over it:
*
*
* SortedBag bag = BagUtils.synchronizedSortedBag(new TreeBag());
* ...
* synchronized(bag) {
* Iterator i = bag.iterator(); // Must be in synchronized block
* while (i.hasNext())
* foo(i.next());
* }
* }
*
*
* Failure to follow this advice may result in non-deterministic
* behavior.
*
* @param bag the bag to synchronize, must not be null
* @return a synchronized bag backed by that bag
* @throws IllegalArgumentException if the SortedBag is null
*/
public static SortedBag synchronizedSortedBag(SortedBag bag) {
return SynchronizedSortedBag.decorate(bag);
}
/**
* Returns an unmodifiable view of the given sorted bag. Any modification
* attempts to the returned bag will raise an
* {@link UnsupportedOperationException}.
*
* @param bag the bag whose unmodifiable view is to be returned, must not be null
* @return an unmodifiable view of that bag
* @throws IllegalArgumentException if the SortedBag is null
*/
public static SortedBag unmodifiableSortedBag(SortedBag bag) {
return UnmodifiableSortedBag.decorate(bag);
}
/**
* Returns a predicated sorted bag backed by the given sorted bag.
* Only objects that pass the test in the given predicate can be
* added to the bag.
* It is important not to use the original bag after invoking this
* method, as it is a backdoor for adding unvalidated objects.
*
* @param bag the sorted bag to predicate, must not be null
* @param predicate the predicate for the bag, must not be null
* @return a predicated bag backed by the given bag
* @throws IllegalArgumentException if the SortedBag or Predicate is null
*/
public static SortedBag predicatedSortedBag(SortedBag bag, Predicate predicate) {
return PredicatedSortedBag.decorate(bag, predicate);
}
/**
* Returns a typed sorted bag backed by the given bag.
*
* Only objects of the specified type can be added to the bag.
*
* @param bag the bag to limit to a specific type, must not be null
* @param type the type of objects which may be added to the bag
* @return a typed bag backed by the specified bag
*/
public static SortedBag typedSortedBag(SortedBag bag, Class type) {
return TypedSortedBag.decorate(bag, type);
}
/**
* Returns a transformed sorted bag backed by the given bag.
*
* Each object is passed through the transformer as it is added to the
* Bag. It is important not to use the original bag after invoking this
* method, as it is a backdoor for adding untransformed objects.
*
* @param bag the bag to predicate, must not be null
* @param transformer the transformer for the bag, must not be null
* @return a transformed bag backed by the given bag
* @throws IllegalArgumentException if the Bag or Transformer is null
*/
public static SortedBag transformedSortedBag(SortedBag bag, Transformer transformer) {
return TransformedSortedBag.decorate(bag, transformer);
}
}