io.ebeaninternal.server.util.ArrayStack Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of ebean Show documentation

composite of common runtime dependencies for all platforms

There is a newer version: 15.8.1

package io.ebeaninternal.server.util;

import java.util.ArrayList;
import java.util.EmptyStackException;

/**
 * Stack based on ArrayList.
 *
 * @author rbygrave
 */
public class ArrayStack {

  private final ArrayList list;

  /**
   * Creates an empty Stack with an initial size.
   */
  public ArrayStack(int size) {
    this.list = new ArrayList<>(size);
  }

  /**
   * Creates an empty Stack.
   */
  public ArrayStack() {
    this.list = new ArrayList<>();
  }

  @Override
  public String toString() {
    return list.toString();
  }

  /**
   * Pushes an item onto the top of this stack.
   */
  public void push(E item) {
    list.add(item);
  }

  /**
   * Removes the object at the top of this stack and returns that object as
   * the value of this function.
   */
  public E pop() {
    int len = list.size();
    if (len == 0) {
      throw new EmptyStackException();
    }
    return list.remove(len - 1);
  }

  protected E peekZero(boolean retNull) {
    int len = list.size();
    if (len == 0) {
      if (retNull) {
        return null;
      }
      throw new EmptyStackException();
    }
    return list.get(len - 1);
  }

  /**
   * Returns the object at the top of this stack without removing it.
   */
  public E peek() {
    return peekZero(false);
  }

  /**
   * Returns the object at the top of this stack without removing it.
   * If the stack is empty this returns null.
   */
  public E peekWithNull() {
    return peekZero(true);
  }

  /**
   * Tests if this stack is empty.
   */
  public boolean isEmpty() {
    return list.isEmpty();
  }

  public int size() {
    return list.size();
  }

  public boolean contains(Object o) {
    //noinspection SuspiciousMethodCalls
    return list.contains(o);
  }
}