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The cloning library is a small, open source (Apache licensed) Java library which deep-clones objects. The objects do not have to implement the Cloneable interface. Effectively, this library can clone ANY Java object. It can be used i.e. in cache implementations, if you don't want the cached object to be modified or whenever you want to create a deep copy of an object.

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package com.rits.perspectives;

import java.util.Collection;

import com.rits.cloning.Cloner;

/**
 * Perspectives: an object instance of a class behaving differently according to the "view angle".
 *  
 * @author kostantinos.kougios
 *
 * 30 Nov 2009
 */
public class Perspectives
{
	private final Cloner	cloner;

	public Perspectives(final Cloner cloner)
	{
		this.cloner = cloner;
	}

	/**
	 * Sample: if o is an instance of Product and c is OrderedProduct.class then this returns
	 * and instance of OrderedProduct.class which has equal field values to those of the instance of Product.
	 * In other words, the returned instance of OrderedProduct.class is the Product instance from the perspective
	 * of an OrderedProduct
	 * 
	 * View an object o from the perspective of class c. (view o as an instance of c). c must be instanceof o.getClass() 
	 * 
	 * @param 		the object
	 * @param 		this will be the returned type and it must be instanceof T. All properties of o will be copied to this instance.
	 * @param c			the class of E. This is used to generate new instances of c
	 * @param o			the object that must be viewed from a different perspective
	 * @return			the E perspective of o
	 */
	public  E viewAs(final Class c, final T o)
	{
		if (o == null) return null;
		if (o instanceof Collection) throw new IllegalArgumentException("for collections please use viewCollectionAs() method. Invalid object " + o);
		final E newInstance = cloner.fastCloneOrNewInstance(c);
		cloner.copyPropertiesOfInheritedClass(o, newInstance);
		return newInstance;
	}

	/**
	 * Sample: if o is a [ Products extends LinkedList ] then the returned instance 
	 * is a [ OrderedProducts extends LinkedList ].
	 * 
	 * View a collection o from the perspective of collection E.
	 * 
	 * NOTE: order of the items might not be preserved, depending on the collection type
	 * 
	 * @param 								the type of the collection o
	 * @param 								the type of the elements of the collection o
	 * @param 								the type of the perspective collection
	 * @param 								the type of the perspective's elements
	 * @param newCollection			the collection to which the adapted instances should be added
	 * @param currentCollection			the collection with the instances to be adapted
	 * @param perspectiveCollectionItemClass	the class of the NI
	 * @return									E, the collection from a different perspective or null if currentCollection is null
	 */
	public , E extends Collection> E viewCollectionAs(final E newCollection, final Class perspectiveCollectionItemClass, final T currentCollection)
	{
		if (currentCollection == null) return null;
		for (final I item : currentCollection)
		{
			final NI newItem = viewAs(perspectiveCollectionItemClass, item);
			newCollection.add(newItem);
		}
		return newCollection;
	}
}