content: /**
   * ========================================
   * JCommon : a free Java report library
   * ========================================
   *
   * Project Info:  http://www.jfree.org/jcommon/
   *
   * (C) Copyright 2000-2006, by Object Refinery Limited and Contributors.
   *
   * This library is free software; you can redistribute it and/or modify it under the terms
   * of the GNU Lesser General Public License as published by the Free Software Foundation;
   * either version 2.1 of the License, or (at your option) any later version.
   *
   * This library 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.
   * See the GNU Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public License along with this
   * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
   * Boston, MA 02111-1307, USA.
   *
   * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
   * in the United States and other countries.]
   *
   * ------------
   * $Id: FastStack.java,v 1.3 2008/09/10 09:22:05 mungady Exp $
   * ------------
   * (C) Copyright 2002-2006, by Object Refinery Limited.
   */
  
  package org.jfree.util;
  
  import java.io.Serializable;
  import java.util.Arrays;
  import java.util.EmptyStackException;
  
  /**
   * A very simple unsynchronized stack. This one is faster than the
   * java.util-Version.
   *
   * @author Thomas Morgner
   */
  public final class FastStack implements Serializable, Cloneable {
      private Object[] contents;
      private int size;
      private int initialSize;
  
      /**
       * Creates a new empty stack.
       */
      public FastStack() {
          this.initialSize = 10;
      }
  
      /**
       * Creates a new empty stack with the specified initial storage size.
       *
       * @param size  the initial storage elements.
       */
      public FastStack(int size) {
          this.initialSize = Math.max(1, size);
      }
  
      /**
       * Returns <code>true</code> if the stack is empty, and <code>false</code>
       * otherwise.
       *
       * @return A boolean.
       */
      public boolean isEmpty() {
          return this.size == 0;
      }
  
      /**
       * Returns the number of elements in the stack.
       *
       * @return The element count.
       */
      public int size() {
          return this.size;
      }
  
      /**
       * Pushes an object onto the stack.
       *
       * @param o  the object.
       */
      public void push(Object o) {
          if (this.contents == null) {
              this.contents = new Object[this.initialSize];
              this.contents[0] = o;
              this.size = 1;
              return;
          }
  
          final int oldSize = this.size;
          this.size += 1;
          if (this.contents.length == this.size) {
              // grow ..
              final Object[] newContents = new Object[this.size
                      + this.initialSize];
              System.arraycopy(this.contents, 0, newContents, 0, this.size);
              this.contents = newContents;
          }
          this.contents[oldSize] = o;
      }
  
      /**
       * Returns the object at the top of the stack without removing it.
       *
       * @return The object at the top of the stack.
       */
      public Object peek() {
          if (this.size == 0) {
              throw new EmptyStackException();
          }
          return this.contents[this.size - 1];
      }
  
      /**
       * Removes and returns the object from the top of the stack.
       *
       * @return The object.
       */
      public Object pop() {
          if (this.size == 0) {
              throw new EmptyStackException();
          }
          this.size -= 1;
          final Object retval = this.contents[this.size];
          this.contents[this.size] = null;
          return retval;
      }
  
      /**
       * Returns a clone of the stack.
       *
       * @return A clone.
       */
      public Object clone() {
          try {
              FastStack stack = (FastStack) super.clone();
              if (this.contents != null) {
                  stack.contents = (Object[]) this.contents.clone();
              }
              return stack;
          }
          catch (CloneNotSupportedException cne) {
              throw new IllegalStateException("Clone not supported? Why?");
          }
      }
  
      /**
       * Clears the stack.
       */
      public void clear() {
          this.size = 0;
          if (this.contents != null) {
              Arrays.fill(this.contents, null);
          }
      }
  
      /**
       * Returns the item at the specified slot in the stack.
       *
       * @param index  the index.
       *
       * @return The item.
       */
      public Object get(final int index) {
          if (index >= this.size) {
              throw new IndexOutOfBoundsException();
          }
          return this.contents[index];
      }
  }
  