85 lines
3.1 KiB
Java
85 lines
3.1 KiB
Java
// collectionsindepth/Utilities.java
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// (c)2016 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://mindviewinc.com/Books/OnJava/ for more book information.
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// Simple demonstrations of the Collections utilities
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import java.util.*;
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public class Utilities {
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static List<String> list = Arrays.asList(
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"one Two three Four five six one".split(" "));
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public static void main(String[] args) {
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System.out.println(list);
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System.out.println("'list' disjoint (Four)?: " +
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Collections.disjoint(list,
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Collections.singletonList("Four")));
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System.out.println("max: " + Collections.max(list));
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System.out.println("min: " + Collections.min(list));
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System.out.println(
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"max w/ comparator: " + Collections.max(list,
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String.CASE_INSENSITIVE_ORDER));
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System.out.println(
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"min w/ comparator: " + Collections.min(list,
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String.CASE_INSENSITIVE_ORDER));
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List<String> sublist =
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Arrays.asList("Four five six".split(" "));
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System.out.println("indexOfSubList: " +
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Collections.indexOfSubList(list, sublist));
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System.out.println("lastIndexOfSubList: " +
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Collections.lastIndexOfSubList(list, sublist));
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Collections.replaceAll(list, "one", "Yo");
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System.out.println("replaceAll: " + list);
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Collections.reverse(list);
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System.out.println("reverse: " + list);
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Collections.rotate(list, 3);
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System.out.println("rotate: " + list);
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List<String> source =
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Arrays.asList("in the matrix".split(" "));
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Collections.copy(list, source);
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System.out.println("copy: " + list);
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Collections.swap(list, 0, list.size() - 1);
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System.out.println("swap: " + list);
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Collections.shuffle(list, new Random(47));
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System.out.println("shuffled: " + list);
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Collections.fill(list, "pop");
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System.out.println("fill: " + list);
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System.out.println("frequency of 'pop': " +
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Collections.frequency(list, "pop"));
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List<String> dups = Collections.nCopies(3, "snap");
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System.out.println("dups: " + dups);
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System.out.println("'list' disjoint 'dups'?: " +
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Collections.disjoint(list, dups));
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// Getting an old-style Enumeration:
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Enumeration<String> e = Collections.enumeration(dups);
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Vector<String> v = new Vector<>();
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while(e.hasMoreElements())
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v.addElement(e.nextElement());
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// Converting an old-style Vector
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// to a List via an Enumeration:
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ArrayList<String> arrayList =
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Collections.list(v.elements());
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System.out.println("arrayList: " + arrayList);
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}
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}
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/* Output:
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[one, Two, three, Four, five, six, one]
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'list' disjoint (Four)?: false
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max: three
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min: Four
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max w/ comparator: Two
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min w/ comparator: five
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indexOfSubList: 3
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lastIndexOfSubList: 3
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replaceAll: [Yo, Two, three, Four, five, six, Yo]
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reverse: [Yo, six, five, Four, three, Two, Yo]
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rotate: [three, Two, Yo, Yo, six, five, Four]
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copy: [in, the, matrix, Yo, six, five, Four]
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swap: [Four, the, matrix, Yo, six, five, in]
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shuffled: [six, matrix, the, Four, Yo, five, in]
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fill: [pop, pop, pop, pop, pop, pop, pop]
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frequency of 'pop': 7
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dups: [snap, snap, snap]
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'list' disjoint 'dups'?: true
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arrayList: [snap, snap, snap]
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*/
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