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SchemaCrawler is an open-source Java API that makes working with database metadata as easy as working with plain old Java objects. SchemaCrawler is also a database schema discovery and comprehension, and schema documentation tool. You can search for database schema objects using regular expressions, and output the schema and data in a readable text format. The output is designed to be diff-ed against other database schemas.

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/*
========================================================================
SchemaCrawler
http://www.schemacrawler.com
Copyright (c) 2000-2024, Sualeh Fatehi .
All rights reserved.
------------------------------------------------------------------------

SchemaCrawler is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SchemaCrawler and the accompanying materials are made available under
the terms of the Eclipse Public License v1.0, GNU General Public License
v3 or GNU Lesser General Public License v3.

You may elect to redistribute this code under any of these licenses.

The Eclipse Public License is available at:
http://www.eclipse.org/legal/epl-v10.html

The GNU General Public License v3 and the GNU Lesser General Public
License v3 are available at:
http://www.gnu.org/licenses/

========================================================================
*/

package us.fatehi.utility.collections;

import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

public class CircularBoundedList implements Iterable {

  private class CyclicalBoundedListIterator implements Iterator {
    private int currentIndex;
    private int remainingElements;

    public CyclicalBoundedListIterator() {
      currentIndex = head;
      remainingElements = size;
    }

    @Override
    public boolean hasNext() {
      return remainingElements > 0;
    }

    @Override
    @SuppressWarnings("unchecked")
    public T next() {
      if (!hasNext()) {
        throw new IllegalStateException("No more elements");
      }
      final T element = (T) elements[currentIndex];
      currentIndex = (currentIndex + 1) % elements.length;
      remainingElements--;
      return element;
    }
  }

  private final Object[] elements;

  private int size;
  private int head;
  private int tail;
  private boolean isFull;

  public CircularBoundedList(final int capacity) {
    if (capacity <= 0) {
      throw new IllegalArgumentException("Capacity must be a positive integer");
    }
    elements = new Object[capacity];
    size = 0;
    head = 0;
    tail = 0;
    isFull = false;
  }

  public void add(final T element) {
    elements[tail] = element;
    tail = (tail + 1) % elements.length;
    if (size < elements.length) {
      size++;
    } else {
      head = (head + 1) % elements.length;
    }
    isFull = size == elements.length;
  }

  public List convertToList() {
    return StreamSupport.stream(((Iterable) this).spliterator(), false)
        .collect(Collectors.toList());
  }

  @SuppressWarnings("unchecked")
  public T get(final int index) {
    if (index < 0 || index >= size) {
      throw new IndexOutOfBoundsException("Invalid index");
    }
    final int actualIndex = (head + index) % elements.length;
    return (T) elements[actualIndex];
  }

  public boolean isEmpty() {
    return size == 0;
  }

  public boolean isFull() {
    return isFull;
  }

  @Override
  public Iterator iterator() {
    return new CyclicalBoundedListIterator();
  }

  public int size() {
    return size;
  }
}