Create a typesafe copy of a raw list. : Generic Collections « Generics « Java Tutorial






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import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.RandomAccess;

/**
 * @since 4.37
 * @author Jaroslav Tulach
 */


public class Utils {

  /**
   * Create a typesafe copy of a raw list.
   * @param rawList an unchecked list
   * @param type the desired supertype of the entries
   * @param strict true to throw a <code>ClassCastException</code> if the raw list has an invalid entry,
   *               false to skip over such entries (warnings may be logged)
   * @return a typed list guaranteed to contain only entries assignable
   *         to the named type (or they may be null)
   * @throws ClassCastException if some entry in the raw list was not well-typed, and only if <code>strict</code> was true
   */
  public static <E> List<E> checkedListByCopy(List rawList, Class<E> type, boolean strict) throws ClassCastException {
      List<E> l = (rawList instanceof RandomAccess) ? new ArrayList<E>(rawList.size()) : new LinkedList<E>();
      Iterator it = rawList.iterator();
      while (it.hasNext()) {
          Object e = it.next();
          try {
              l.add(type.cast(e));
          } catch (ClassCastException x) {
              if (strict) {
                  throw x;
              } else {
                  System.out.println("not assignable ");
              }
          }
      }
      return l;
  }
}








12.2.Generic Collections
12.2.1.Generics and Collections: ArrayList
12.2.2.Arrays: Storing class objects in Array as data items
12.2.3.Using Generic Comparable interface
12.2.4.A generic first-in, first-out bounded collection of objects
12.2.5.A list declared to hold objects of a type T can also hold objects that extend from T.
12.2.6.Utilities for generic ArrayList
12.2.7.Your own tree with generic user object
12.2.8.Generic to list
12.2.9.Create a typesafe copy of a raw list.
12.2.10.Create a typesafe copy of a raw map.
12.2.11.Create a typesafe filter of an unchecked iterator.
12.2.12.Create a typesafe view over an underlying raw set.
12.2.13.Create a typesafe view over an underlying raw map.
12.2.14.Create a typesafe filter of an unchecked enumeration.