39 lines
1.0 KiB
Java
39 lines
1.0 KiB
Java
// references/CloneArrayList.java
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// (c)2017 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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// The clone() operation works for only a few
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// items in the standard Java library
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import java.util.*;
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import java.util.stream.*;
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class Int {
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private int i;
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Int(int ii) { i = ii; }
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public void increment() { i++; }
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@Override
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public String toString() {
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return Integer.toString(i);
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}
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}
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public class CloneArrayList {
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public static void main(String[] args) {
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ArrayList<Int> v = IntStream.range(0, 10)
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.mapToObj(Int::new)
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.collect(Collectors
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.toCollection(ArrayList::new));
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System.out.println("v: " + v);
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@SuppressWarnings("unchecked")
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ArrayList<Int> v2 = (ArrayList<Int>)v.clone();
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// Increment all v2's elements:
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v2.forEach(Int::increment);
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// See if it changed v's elements:
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System.out.println("v: " + v);
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}
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}
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/* Output:
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v: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
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v: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
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*/
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