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    <p>I had the same problem some time ago and was disappointed because I couldn't find any solution that suites my needs so I wrote my own class. Honestly, I did found some code back then, but even that wasn't what I was searching for so I adapted it and now I'm sharing it, just like the author of that piece of code did. </p> <p>EDIT: This is the original (although slightly different) code: <a href="http://www.museful.net/2011/software-development/circulararraylist-for-java" rel="nofollow">CircularArrayList for java</a></p> <p>I don't have the link of the source because it was time ago, but here's the code:</p> <pre><code>import java.util.AbstractList; import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.RandomAccess; public class CircularArrayList&lt;E&gt; extends AbstractList&lt;E&gt; implements RandomAccess { private final int n; // buffer length private final List&lt;E&gt; buf; // a List implementing RandomAccess private int leader = 0; private int size = 0; public CircularArrayList(int capacity) { n = capacity + 1; buf = new ArrayList&lt;E&gt;(Collections.nCopies(n, (E) null)); } public int capacity() { return n - 1; } private int wrapIndex(int i) { int m = i % n; if (m &lt; 0) { // modulus can be negative m += n; } return m; } @Override public int size() { return this.size; } @Override public E get(int i) { if (i &lt; 0 || i &gt;= n-1) throw new IndexOutOfBoundsException(); if(i &gt; size()) throw new NullPointerException("Index is greater than size."); return buf.get(wrapIndex(leader + i)); } @Override public E set(int i, E e) { if (i &lt; 0 || i &gt;= n-1) { throw new IndexOutOfBoundsException(); } if(i == size()) // assume leader's position as invalid (should use insert(e)) throw new IndexOutOfBoundsException("The size of the list is " + size() + " while the index was " + i +". Please use insert(e) method to fill the list."); return buf.set(wrapIndex(leader - size + i), e); } public void insert(E e) { int s = size(); buf.set(wrapIndex(leader), e); leader = wrapIndex(++leader); buf.set(leader, null); if(s == n-1) return; // we have replaced the eldest element. this.size++; } @Override public void clear() { int cnt = wrapIndex(leader-size()); for(; cnt != leader; cnt = wrapIndex(++cnt)) this.buf.set(cnt, null); this.size = 0; } public E removeOldest() { int i = wrapIndex(leader+1); for(;;i = wrapIndex(++i)) { if(buf.get(i) != null) break; if(i == leader) throw new IllegalStateException("Cannot remove element." + " CircularArrayList is empty."); } this.size--; return buf.set(i, null); } @Override public String toString() { int i = wrapIndex(leader - size()); StringBuilder str = new StringBuilder(size()); for(; i != leader; i = wrapIndex(++i)){ str.append(buf.get(i)); } return str.toString(); } public E getOldest(){ int i = wrapIndex(leader+1); for(;;i = wrapIndex(++i)) { if(buf.get(i) != null) break; if(i == leader) throw new IllegalStateException("Cannot remove element." + " CircularArrayList is empty."); } return buf.get(i); } public E getNewest(){ int i = wrapIndex(leader-1); if(buf.get(i) == null) throw new IndexOutOfBoundsException("Error while retrieving the newest element. The Circular Array list is empty."); return buf.get(i); } } </code></pre>
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    1. POJava - Ring Buffer
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    1. COThis might be the source you're referring to: http://www.museful.net/2011/software-development/circulararraylist-for-java
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    2. COYes, that is the original source. (I'll edit my post now.)
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