commons-collections/RELEASE-NOTES.html

<title>RELEASE NOTES: COLLECTIONS 3.0</title>

<center><h2>RELEASE NOTES: COLLECTIONS 3.0</h2></center>

<p><i>Collections 3.0</i> includes a lot of new functionality, including new interfaces
and new implementations in addition to various bug fixes and refactoring changes.
The major additions are:
</p>
<ul>
<li><strong>Bidirectional maps</strong> -
    New interface and implementations for maps that need bidirectional lookup.</li>
<li><strong>Map iterator</strong> -
    New interface to enable iteration over map keys and values in one easy step.</li>
<li><strong>Observable collections</strong> -
    New collection decorators that allow changes to collections to be observed via listeners.</li>
<li><strong>Decorators</strong> -
    An entire package of classes that decorate existing collections/maps to add functionality.
    This includes fixed size, lazy loading, validating, unmodifiable, synchronized, bounded,
    transforming and ordered.</li>
<li><strong>Functors</strong> -
    A default set of functor implementations is now provided for Predicate, Transformer,
    Closure and Factory.</li>
<li><strong>Pairs</strong> -
    A new package full of key-value pairs and map entry implementations.</li>
</ul>
<p>
All previously deprecated classes have been removed.
</p>

<hr />

<center><h3>
NEW PACKAGES
</h3></center>

<p>These packages are new to <i>Collections 3.0</i>:</p>

<ul>
<li><strong>decorators</strong> - 
	Package of classes that decorate other collections/maps. Some of these classes
	were previously inner classes, others are new.</li>
	
<li><strong>observed</strong> - 
	Package of classes that enable changes to collections/maps to be observed.</li>
	
<li><strong>pairs</strong> - 
	Package of key-value pairs and map entries.</li>
</ul>

<center><h3>
NEW CLASSES
</h3></center>

<p>These collections are new to <i>Collections 3.0</i>:</p>

<ul>
</ul>

<p>These comparators are new to <i>Collections 3.0</i>:</p>

<ul>
<li><strong>BooleanIterator</strong> - 
	Provides a comparator over Boolean instances.</li>

<li><strong>FixedOrderIterator</strong> - 
	Provides an iterator in a fixed pre-determined order.</li>
</ul>

<p>These iterators are new to <i>Collections 3.0</i>:</p>

<ul>
<li><strong>MapIterator</strong> - 
	Interface that defines a simple and powerful way to iterate over a Map.</li>

<li><strong>Resetable*Iterator</strong> - 
	Interfaces that defines a reset() method to reset the iterator back to the start.</li>

<li><strong>ArrayListIterator</strong> - 
    Provides a ListIterator over an array of any type (including primitive arrays).</li>

<li><strong>LoopingIterator</strong> - 
    Provides an Iterator that loops repeatedly over the collection.</li>

<li><strong>ObjectArray*Iterator</strong> - 
	Provides iterators over an Object array.</li>

<li><strong>Abstract*IteratorDecorator</strong> - 
	Provides abstract decorators that can be used to build extra functionality.</li>

<li><strong>Unmodifiable*Iterator</strong> - 
	Provides decorators for iterators that are unmodifiable.</li>
</ul>

<p>These are the new utility classes:</p>

<ul>
</ul>


<hr />

<center><h3>CHANGED CLASSES</h3></center>

<p>These comparators have changed since <i>Collections 3.0</i>:</p>

<ul>
<li><strong>ComparableComparator</strong> - 
	Simpler implementation that respects interface better.</li>
	
<li><strong>ComparatorChain</strong> - 
	Equals and HashCode added.</li>
	
<li><strong>ReverseComparator</strong> - 
	Equals and HashCode added.</li>
</ul>

<p>These iterators have changed since <i>Collections 3.0</i>:</p>

<ul>
<li><strong>ArrayIterator</strong> - 
	This now implements the ResetableIterator interface. It also supports a start index to iterate from.</li>

<li><strong>CollatingIterator</strong> - 
	The remove() method now throws IllegalStateException not NoSuchElementException.</li>

<li><strong>FilterIterator</strong> - 
	The remove() method is now supported, with some limitations.</li>

<li><strong>IteratorChain</strong> - 
	Bug fix for when remove() called before hasNext()/next().</li>

<li><strong>Singleton*Iterator</strong> - 
	These now implement the ResetableIterator interface.</li>

<li><strong>Proxy*Iterator</strong> - 
	Now deprecated in favour of AbstractIteratorDecorator/AbstractListIteratorDecorator.</li>

<li><strong>Filter*Iterator/TransformIterator</strong> - 
	No longer extend ProxyIterator.</li>
</ul>


<hr />


<center><h3>REFACTORING</h3></center>

<p><u>Documentation</u></p>

<p>Every class released in 3.0 has been changed in some way.
This might be simply the update to the Apache license, or it could be improved Javadoc.</p>