48 lines
1.2 KiB
Java
48 lines
1.2 KiB
Java
// streams/MapCollector.java
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// (c)2021 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 Pair {
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public final Character c;
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public final Integer i;
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Pair(Character c, Integer i) {
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this.c = c;
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this.i = i;
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}
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public Character getC() { return c; }
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public Integer getI() { return i; }
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@Override public String toString() {
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return "Pair(" + c + ", " + i + ")";
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}
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}
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class RandomPair {
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Random rand = new Random(47);
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// An infinite iterator of random capital letters:
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Iterator<Character> capChars = rand.ints(65,91)
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.mapToObj(i -> (char)i)
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.iterator();
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public Stream<Pair> stream() {
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return rand.ints(100, 1000).distinct()
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.mapToObj(i -> new Pair(capChars.next(), i));
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}
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}
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public class MapCollector {
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public static void main(String[] args) {
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Map<Integer, Character> map =
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new RandomPair().stream()
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.limit(8)
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.collect(
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Collectors.toMap(Pair::getI, Pair::getC));
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System.out.println(map);
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}
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}
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/* Output:
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{688=W, 309=C, 293=B, 761=N, 858=N, 668=G, 622=F,
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751=N}
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*/
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