69 lines
2.4 KiB
Java
69 lines
2.4 KiB
Java
// understandingcollections/Unsupported.java
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// (c)2016 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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// Unsupported operations in Java collections
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import java.util.*;
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public class Unsupported {
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static void test(String msg, List<String> list) {
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System.out.println("--- " + msg + " ---");
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Collection<String> c = list;
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Collection<String> subList = list.subList(1,8);
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// Copy of the sublist:
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Collection<String> c2 = new ArrayList<>(subList);
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try { c.retainAll(c2); } catch(Exception e) {
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System.out.println("retainAll(): " + e);
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}
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try { c.removeAll(c2); } catch(Exception e) {
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System.out.println("removeAll(): " + e);
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}
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try { c.clear(); } catch(Exception e) {
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System.out.println("clear(): " + e);
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}
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try { c.add("X"); } catch(Exception e) {
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System.out.println("add(): " + e);
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}
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try { c.addAll(c2); } catch(Exception e) {
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System.out.println("addAll(): " + e);
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}
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try { c.remove("C"); } catch(Exception e) {
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System.out.println("remove(): " + e);
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}
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// The List.set() method modifies the value but
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// doesn't change the size of the data structure:
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try {
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list.set(0, "X");
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} catch(Exception e) {
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System.out.println("List.set(): " + e);
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}
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}
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public static void main(String[] args) {
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List<String> list =
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Arrays.asList("A B C D E F G H I J K L".split(" "));
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test("Modifiable Copy", new ArrayList<>(list));
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test("Arrays.asList()", list);
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test("unmodifiableList()",
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Collections.unmodifiableList(
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new ArrayList<>(list)));
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}
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}
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/* Output:
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--- Modifiable Copy ---
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--- Arrays.asList() ---
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retainAll(): java.lang.UnsupportedOperationException
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removeAll(): java.lang.UnsupportedOperationException
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clear(): java.lang.UnsupportedOperationException
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add(): java.lang.UnsupportedOperationException
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addAll(): java.lang.UnsupportedOperationException
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remove(): java.lang.UnsupportedOperationException
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--- unmodifiableList() ---
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retainAll(): java.lang.UnsupportedOperationException
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removeAll(): java.lang.UnsupportedOperationException
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clear(): java.lang.UnsupportedOperationException
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add(): java.lang.UnsupportedOperationException
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addAll(): java.lang.UnsupportedOperationException
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remove(): java.lang.UnsupportedOperationException
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List.set(): java.lang.UnsupportedOperationException
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*/
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