PopupFactory.java   [plain text]

/* PopupFactory.java --
   Copyright (C) 2003 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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General Public License for more details.

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02111-1307 USA.

Linking this library statically or dynamically with other modules is
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permission to link this library with independent modules to produce an
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package javax.swing;

import java.awt.Component;


/**
 * A factory for <code>Popup</code> objects. These are used to
 * managed little windows that float over everything else,
 * typically containing a popup menu.
 *
 * @since 1.4
 *
 * @author Sascha Brawer (brawer@dandelis.ch)
 */
public class PopupFactory
{
  /**
   * The shared factory object.
   *
   * @see #getSharedFactory
   * @see #setSharedFactory
   */
  private static PopupFactory sharedFactory;


  /**
   * Constructs a new <code>PopupFactory</code>. Usually, a single
   * <code>PopupFactory</code> is shared among multiple consumers
   * of <code>Popup</code>. Use {@link #getSharedInstance} to retrieve
   * the current factory.
   */
  public PopupFactory()
  {
  }


  /**
   * Sets the shared factory.
   *
   * @param factory the PopupFactory that future invocations of
   *        {@link #getSharedInstance} will return.
   *
   * @throws IllegalArgumentException if <code>factory</code>
   *         is <code>null</code>.
   */
  public static void setSharedInstance(PopupFactory factory)
  {
    if (factory == null)
      throw new IllegalArgumentException();

    /* Swing is not designed to be thread-safe, so there is no
     * need to synchronize the access to the global variable.
     */
    sharedFactory = factory;
  }


  /**
   * Retrieves the shared factory, creating a new factory if
   * necessary.
   *
   * @return a <code>PopupFactory</code> that can be used
   *         to create <code>Popup</code> objects.
   */
  public static PopupFactory getSharedInstance()
  {
    /* Swing is not designed to be thread-safe, so there is no
     * need to synchronize the access to the global variable.
     */
    if (sharedFactory == null)
      sharedFactory = new PopupFactory();

    return sharedFactory;
  }


  /**
   * Creates a new <code>Popup</code> given its owner,
   * contents and the screen position where the popup
   * will appear.
   *
   * @param owner the Component to which <code>x</code> and
   *        <code>y</code> are relative, or <code>null</code> for
   *        placing the popup relative to the origin of the screen.
   *
   * @param contents the contents that will be displayed inside
   *        the <code>Popup</code>.
   *
   * @param x the horizontal position where the Popup will appear.
   *
   * @param y the vertical position where the Popup will appear.
   *
   * @throws IllegalArgumentException if <code>contents</code>
   *         is <code>null</code>.
   */
  public Popup getPopup(Component owner, Component contents,
                        int x, int y)
  {
    return new Popup.JWindowPopup(owner, contents, x, y);
  }
}