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Java Source | 2000-05-25 | 5.2 KB | 142 lines |
- //: Collection1.java
- //////////////////////////////////////////////////
- // Copyright (c) Bruce Eckel, 1998
- // Source code file from the book "Thinking in Java"
- // All rights reserved EXCEPT as allowed by the
- // following statements: You can freely use this file
- // for your own work (personal or commercial),
- // including modifications and distribution in
- // executable form only. Permission is granted to use
- // this file in classroom situations, including its
- // use in presentation materials, as long as the book
- // "Thinking in Java" is cited as the source.
- // Except in classroom situations, you cannot copy
- // and distribute this code; instead, the sole
- // distribution point is http://www.BruceEckel.com
- // (and official mirror sites) where it is
- // freely available. You cannot remove this
- // copyright and notice. You cannot distribute
- // modified versions of the source code in this
- // package. You cannot use this file in printed
- // media without the express permission of the
- // author. Bruce Eckel makes no representation about
- // the suitability of this software for any purpose.
- // It is provided "as is" without express or implied
- // warranty of any kind, including any implied
- // warranty of merchantability, fitness for a
- // particular purpose or non-infringement. The entire
- // risk as to the quality and performance of the
- // software is with you. Bruce Eckel and the
- // publisher shall not be liable for any damages
- // suffered by you or any third party as a result of
- // using or distributing software. In no event will
- // Bruce Eckel or the publisher be liable for any
- // lost revenue, profit, or data, or for direct,
- // indirect, special, consequential, incidental, or
- // punitive damages, however caused and regardless of
- // the theory of liability, arising out of the use of
- // or inability to use software, even if Bruce Eckel
- // and the publisher have been advised of the
- // possibility of such damages. Should the software
- // prove defective, you assume the cost of all
- // necessary servicing, repair, or correction. If you
- // think you've found an error, please email all
- // modified files with clearly commented changes to:
- // Bruce@EckelObjects.com. (Please use the same
- // address for non-code errors found in the book.)
- /////////////////////////////////////////////////
-
- // Things you can do with all Collections
- package c08.newcollections;
- import java.util.*;
-
- public class Collection1 {
- // Fill with 'size' elements, start
- // counting at 'start':
- public static Collection
- fill(Collection c, int start, int size) {
- for(int i = start; i < start + size; i++)
- c.add(Integer.toString(i));
- return c;
- }
- // Default to a "start" of 0:
- public static Collection
- fill(Collection c, int size) {
- return fill(c, 0, size);
- }
- // Default to 10 elements:
- public static Collection fill(Collection c) {
- return fill(c, 0, 10);
- }
- // Create & upcast to Collection:
- public static Collection newCollection() {
- return fill(new ArrayList());
- // ArrayList is used for simplicity, but it's
- // only seen as a generic Collection
- // everywhere else in the program.
- }
- // Fill a Collection with a range of values:
- public static Collection
- newCollection(int start, int size) {
- return fill(new ArrayList(), start, size);
- }
- // Moving through a List with an iterator:
- public static void print(Collection c) {
- for(Iterator x = c.iterator(); x.hasNext();)
- System.out.print(x.next() + " ");
- System.out.println();
- }
- public static void main(String[] args) {
- Collection c = newCollection();
- c.add("ten");
- c.add("eleven");
- print(c);
- // Make an array from the List:
- Object[] array = c.toArray();
- // Make a String array from the List:
- String[] str =
- (String[])c.toArray(new String[1]);
- // Find max and min elements; this means
- // different things depending on the way
- // the Comparable interface is implemented:
- System.out.println("Collections.max(c) = " +
- Collections.max(c));
- System.out.println("Collections.min(c) = " +
- Collections.min(c));
- // Add a Collection to another Collection
- c.addAll(newCollection());
- print(c);
- c.remove("3"); // Removes the first one
- print(c);
- c.remove("3"); // Removes the second one
- print(c);
- // Remove all components that are in the
- // argument collection:
- c.removeAll(newCollection());
- print(c);
- c.addAll(newCollection());
- print(c);
- // Is an element in this Collection?
- System.out.println(
- "c.contains(\"4\") = " + c.contains("4"));
- // Is a Collection in this Collection?
- System.out.println(
- "c.containsAll(newCollection()) = " +
- c.containsAll(newCollection()));
- Collection c2 = newCollection(5, 3);
- // Keep all the elements that are in both
- // c and c2 (an intersection of sets):
- c.retainAll(c2);
- print(c);
- // Throw away all the elements in c that
- // also appear in c2:
- c.removeAll(c2);
- System.out.println("c.isEmpty() = " +
- c.isEmpty());
- c = newCollection();
- print(c);
- c.clear(); // Remove all elements
- System.out.println("after c.clear():");
- print(c);
- }
- } ///:~