56 lines
1.5 KiB
Java
56 lines
1.5 KiB
Java
//: references/AddingClone.java
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// You must go through a few gyrations
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// to add cloning to your own class.
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import java.util.*;
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class Int2 implements Cloneable {
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private int i;
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public Int2(int ii) { i = ii; }
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public void increment() { i++; }
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@Override
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public String toString() { return Integer.toString(i); }
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@Override
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public Object clone() {
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Object o = null;
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try {
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o = super.clone();
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} catch(CloneNotSupportedException e) {
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System.err.println("Int2 can't clone");
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}
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return o;
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}
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}
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// Inheritance doesn't remove cloneability:
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class Int3 extends Int2 {
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private int j; // Automatically duplicated
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public Int3(int i) { super(i); }
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}
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public class AddingClone {
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@SuppressWarnings("unchecked")
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public static void main(String[] args) {
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Int2 x = new Int2(10);
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Int2 x2 = (Int2)x.clone();
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x2.increment();
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System.out.println("x = " + x + ", x2 = " + x2);
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// Anything inherited is also cloneable:
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Int3 x3 = new Int3(7);
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x3 = (Int3)x3.clone();
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ArrayList v = new ArrayList();
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for(int i = 0; i < 10; i++ )
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v.add(new Int2(i));
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System.out.println("v: " + v);
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ArrayList v2 = (ArrayList)v.clone();
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// Now clone each element:
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for(int i = 0; i < v.size(); i++)
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v2.set(i, ((Int2)v2.get(i)).clone());
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// Increment all v2's elements:
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for(Iterator e = v2.iterator(); e.hasNext(); )
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((Int2)e.next()).increment();
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System.out.println("v2: " + v2);
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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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