40 lines
1.0 KiB
Java
40 lines
1.0 KiB
Java
// generics/GenericArray2.java
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// (c)2020 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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public class GenericArray2<T> {
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private Object[] array;
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public GenericArray2(int sz) {
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array = new Object[sz];
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}
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public void put(int index, T item) {
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array[index] = item;
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}
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@SuppressWarnings("unchecked")
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public T get(int index) { return (T)array[index]; }
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@SuppressWarnings("unchecked")
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public T[] rep() {
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return (T[])array; // Unchecked cast
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}
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public static void main(String[] args) {
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GenericArray2<Integer> gai =
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new GenericArray2<>(10);
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for(int i = 0; i < 10; i ++)
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gai.put(i, i);
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for(int i = 0; i < 10; i ++)
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System.out.print(gai.get(i) + " ");
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System.out.println();
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try {
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Integer[] ia = gai.rep();
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} catch(Exception e) {
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System.out.println(e);
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}
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}
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}
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/* Output:
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0 1 2 3 4 5 6 7 8 9
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java.lang.ClassCastException: [Ljava.lang.Object;
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cannot be cast to [Ljava.lang.Integer;
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*/
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