48 lines
1.2 KiB
Java
48 lines
1.2 KiB
Java
// generics/GenericCast.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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import java.util.*;
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import java.util.stream.*;
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class FixedSizeStack<T> {
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private final int size;
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private Object[] storage;
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private int index = 0;
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FixedSizeStack(int size) {
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this.size = size;
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storage = new Object[size];
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}
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public void push(T item) {
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if(index < size)
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storage[index++] = item;
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}
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@SuppressWarnings("unchecked")
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public T pop() {
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return index == 0 ? null : (T)storage[--index];
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}
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@SuppressWarnings("unchecked")
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Stream<T> stream() {
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return (Stream<T>)Arrays.stream(storage);
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}
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}
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public class GenericCast {
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static String[] letters =
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"ABCDEFGHIJKLMNOPQRS".split("");
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public static void main(String[] args) {
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FixedSizeStack<String> strings =
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new FixedSizeStack<>(letters.length);
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Arrays.stream("ABCDEFGHIJKLMNOPQRS".split(""))
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.forEach(strings::push);
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System.out.println(strings.pop());
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strings.stream()
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.map(s -> s + " ")
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.forEach(System.out::print);
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}
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}
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/* Output:
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S
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A B C D E F G H I J K L M N O P Q R S
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*/
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