44 lines
1.3 KiB
Java
44 lines
1.3 KiB
Java
// containers/AdapterMethodIdiom.java
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// ©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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// The "Adapter Method" idiom uses for-in
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// with additional kinds of Iterables.
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import java.util.*;
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class ReversibleArrayList<T> extends ArrayList<T> {
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public ReversibleArrayList(Collection<T> c) { super(c); }
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public Iterable<T> reversed() {
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return () -> new Iterator<T>() { // <* Describe *>
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int current = size() - 1;
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@Override
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public boolean hasNext() { return current > -1; }
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@Override
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public T next() { return get(current--); }
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@Override
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public void remove() { // Not implemented
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throw new UnsupportedOperationException();
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}
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};
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}
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}
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public class AdapterMethodIdiom {
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public static void main(String[] args) {
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ReversibleArrayList<String> ral =
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new ReversibleArrayList<>(
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Arrays.asList("To be or not to be".split(" ")));
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// Grabs the ordinary iterator via iterator():
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for(String s : ral)
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System.out.print(s + " ");
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System.out.println();
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// Hand it the Iterable of your choice
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for(String s : ral.reversed())
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System.out.print(s + " ");
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}
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}
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/* Output:
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To be or not to be
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be to not or be To
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*/
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