java.util.RandomAccess Maven / Gradle / Ivy
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package java.util;
/**
* Marker interface used by List implementations to indicate that
* they support fast (generally constant time) random access. The primary
* purpose of this interface is to allow generic algorithms to alter their
* behavior to provide good performance when applied to either random or
* sequential access lists.
*
* The best algorithms for manipulating random access lists (such as
* ArrayList) can produce quadratic behavior when applied to
* sequential access lists (such as LinkedList). Generic list
* algorithms are encouraged to check whether the given list is an
* instanceof this interface before applying an algorithm that would
* provide poor performance if it were applied to a sequential access list,
* and to alter their behavior if necessary to guarantee acceptable
* performance.
*
*
It is recognized that the distinction between random and sequential
* access is often fuzzy. For example, some List implementations
* provide asymptotically linear access times if they get huge, but constant
* access times in practice. Such a List implementation
* should generally implement this interface. As a rule of thumb, a
* List implementation should implement this interface if,
* for typical instances of the class, this loop:
*
* for (int i=0, n=list.size(); i < n; i++)
* list.get(i);
*
* runs faster than this loop:
*
* for (Iterator i=list.iterator(); i.hasNext(); )
* i.next();
*
*
* This interface is a member of the
*
* Java Collections Framework.
*
* @since 1.4
*/
public interface RandomAccess {
}