/* Dialog.java -- An AWT dialog box
 Copyright (C) 1999, 2000, 2001, 2002, 2005, 2006  
 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
 the Free Software Foundation; either version 2, or (at your option)
 any later version.

 GNU Classpath 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
 General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with GNU Classpath; see the file COPYING.  If not, write to the
 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 02110-1301 USA.

 Linking this library statically or dynamically with other modules is
 making a combined work based on this library.  Thus, the terms and
 conditions of the GNU General Public License cover the whole
 combination.

 As a special exception, the copyright holders of this library give you
 permission to link this library with independent modules to produce an
 executable, regardless of the license terms of these independent
 modules, and to copy and distribute the resulting executable under
 terms of your choice, provided that you also meet, for each linked
 independent module, the terms and conditions of the license of that
 module.  An independent module is a module which is not derived from
 or based on this library.  If you modify this library, you may extend
 this exception to your version of the library, but you are not
 obligated to do so.  If you do not wish to do so, delete this
 exception statement from your version. */


package java.awt;

import java.awt.peer.DialogPeer;

import javax.accessibility.AccessibleContext;
import javax.accessibility.AccessibleRole;
import javax.accessibility.AccessibleState;
import javax.accessibility.AccessibleStateSet;

/**
 * <code>Dialog</code> provides a top-level window normally used to receive 
 * user input in applications.
 * <p>
 * A dialog always has another top-level window as owner and is only visible
 * if this owner is visible to the user. The default layout of dialogs is the 
 * <code>BorderLayout</code>. Dialogs can be modal (blocks user input to other
 * components) or non-modal (user input in other components are allowed).
 * </p> 
 * 
 * @author Aaron M. Renn (arenn@urbanophile.com)
 * @author Tom Tromey (tromey@redhat.com)
 */
public class Dialog extends Window
{
  // Serialization constant
  private static final long serialVersionUID = 5920926903803293709L;

  /**
   * @serial Indicates whether or not this dialog box is modal.
   */
  private boolean modal;

  /**
   * @serial Indicates whether or not this dialog box is resizable.
   */
  private boolean resizable = true;

  /**
   * @serial The title string for this dialog box, which can be
   *         <code>null</code>.
   */
  private String title;

  /**
   * This field indicates whether the dialog is undecorated or not.
   */
  private boolean undecorated = false;

  /**
   * Indicates that we are blocked for modality in show
   */
  private boolean blocked = false;

  /**
   * Secondary EventQueue to handle AWT events while we are blocked for 
   * modality in show.
   */
  private EventQueue eq2 = null;

  /**
   * Initializes a new instance of <code>Dialog</code> with the specified
   * parent, that is resizable and not modal, and which has no title.
   * 
   * @param parent The parent frame of this dialog box.
   * @exception IllegalArgumentException If the owner's GraphicsConfiguration 
   * is not from a screen device, or if owner is null. This exception is 
   * always thrown when GraphicsEnvironment.isHeadless() returns true.
   */
  public Dialog(Frame parent)
  {
    this(parent, "", false);
  }

  /**
   * Initializes a new instance of <code>Dialog</code> with the specified
   * parent and modality, that is resizable and which has no title.
   * 
   * @param parent The parent frame of this dialog box.
   * @param modal <code>true</code> if this dialog box is modal,
   * <code>false</code> otherwise.
   * 
   * @exception IllegalArgumentException If the owner's GraphicsConfiguration
   * is not from a screen device, or if owner is null. This exception is 
   * always thrown when GraphicsEnvironment.isHeadless() returns true.
   */
  public Dialog(Frame parent, boolean modal)
  {
    this(parent, "", modal);
  }

  /**
   * Initializes a new instance of <code>Dialog</code> with the specified
   * parent, that is resizable and not modal, and which has the specified 
   * title.
   * 
   * @param parent The parent frame of this dialog box.
   * @param title The title string for this dialog box.
   * 
   * @exception IllegalArgumentException If the owner's GraphicsConfiguration
   * is not from a screen device, or if owner is null. This exceptionnis 
   * always thrown when GraphicsEnvironment.isHeadless() returns true.
   */
  public Dialog(Frame parent, String title)
  {
    this(parent, title, false);
  }

  /**
   * Initializes a new instance of <code>Dialog</code> with the specified,
   * parent, title, and modality, that is resizable.
   * 
   * @param parent The parent frame of this dialog box.
   * @param title The title string for this dialog box.
   * @param modal <code>true</code> if this dialog box is modal,
   * <code>false</code> otherwise.
   *          
   * @exception IllegalArgumentException If owner is null or
   *              GraphicsEnvironment.isHeadless() returns true.
   */
  public Dialog(Frame parent, String title, boolean modal)
  {
    this(parent, title, modal, parent.getGraphicsConfiguration());
  }

  /**
   * Initializes a new instance of <code>Dialog</code> with the specified,
   * parent, title, modality and <code>GraphicsConfiguration</code>, that is
   * resizable.
   * 
   * @param parent The parent frame of this dialog box.
   * @param title The title string for this dialog box.
   * @param modal <code>true</code> if this dialog box is modal,
   * <code>false</code> otherwise.
   * @param gc The <code>GraphicsConfiguration</code> object to use. If 
   * <code>null</code> the <code>GraphicsConfiguration</code> of the target 
   * frame is used.
   * 
   * @exception IllegalArgumentException If owner is null, the
   *              GraphicsConfiguration is not a screen device or
   *              GraphicsEnvironment.isHeadless() returns true.
   * @since 1.4
   */
  public Dialog(Frame parent, String title, boolean modal,
                GraphicsConfiguration gc)
  {
    super(parent, (gc == null) ? parent.getGraphicsConfiguration() : gc);

    // A null title is equivalent to an empty title
    this.title = (title != null) ? title : "";
    this.modal = modal;
    visible = false;

    setLayout(new BorderLayout());
  }

  /**
   * Initializes a new instance of <code>Dialog</code> with the specified,
   * parent, that is resizable.
   * 
   * @param owner The parent frame of this dialog box.
   * 
   * @exception IllegalArgumentException If parent is null. This exception is
   * always thrown when GraphicsEnvironment.isHeadless() returns true.
   * 
   * @since 1.2
   */
  public Dialog(Dialog owner)
  {
    this(owner, "", false, owner.getGraphicsConfiguration());
  }

  /**
   * Initializes a new instance of <code>Dialog</code> with the specified,
   * parent and title, that is resizable.
   * 
   * @param owner The parent frame of this dialog box.
   * @param title The title string for this dialog box.
   * 
   * @exception IllegalArgumentException If parent is null. This exception is
   *              always thrown when GraphicsEnvironment.isHeadless() returns
   *              true.
   * @since 1.2
   */
  public Dialog(Dialog owner, String title)
  {
    this(owner, title, false, owner.getGraphicsConfiguration());
  }

  /**
   * Initializes a new instance of <code>Dialog</code> with the specified,
   * parent, title and modality, that is resizable.
   * 
   * @param owner The parent frame of this dialog box.
   * @param title The title string for this dialog box.
   * @param modal <code>true</code> if this dialog box is modal,
   * <code>false</code> otherwise.
   * 
   * @exception IllegalArgumentException If parent is null. This exception is
   * always thrown when GraphicsEnvironment.isHeadless() returns true.
   * @since 1.2
   */
  public Dialog(Dialog owner, String title, boolean modal)
  {
    this(owner, title, modal, owner.getGraphicsConfiguration());
  }

  /**
   * Initializes a new instance of <code>Dialog</code> with the specified,
   * parent, title, modality and <code>GraphicsConfiguration</code>, that is
   * resizable.
   * 
   * @param parent The parent frame of this dialog box.
   * @param title The title string for this dialog box.
   * @param modal <code>true</code> if this dialog box is modal,
   * <code>false</code> otherwise.
   * @param gc The <code>GraphicsConfiguration</code> object to use. If 
   * <code>null</code> the <code>GraphicsConfiguration</code> of the target 
   * frame is used.
   * 
   * @exception IllegalArgumentException If parent is null, the
   * GraphicsConfiguration is not a screen device or 
   * GraphicsEnvironment.isHeadless() returns true.
   * 
   * @since 1.4
   */
  public Dialog(Dialog parent, String title, boolean modal,
                GraphicsConfiguration gc)
  {
    super(parent, (gc == null) ? parent.getGraphicsConfiguration() : gc);

    // A null title is equivalent to an empty title
    this.title = (title != null) ? title : "";
    this.modal = modal;
    visible = false;

    setLayout(new BorderLayout());
  }

  /**
   * Returns the title of this dialog box.
   * 
   * @return The title of this dialog box.
   */
  public String getTitle()
  {
    return title;
  }

  /**
   * Sets the title of this dialog box to the specified string.
   * 
   * @param title the new title. If <code>null</code> an empty
   * title will be set.
   */
  public synchronized void setTitle(String title)
  {
    // A null title is equivalent to an empty title
    this.title = (title != null) ? title : "";

    if (peer != null)
      {
        DialogPeer d = (DialogPeer) peer;
        d.setTitle(title);
      }
  }

  /**
   * Tests whether or not this dialog box is modal.
   * 
   * @return <code>true</code> if this dialog box is modal, <code>false</code>
   * otherwise.
   */
  public boolean isModal()
  {
    return modal;
  }

  /**
   * Changes the modality of this dialog box. This can only be done before the
   * peer is created.
   * 
   * @param modal <code>true</code> to make this dialog box modal,
   * <code>false</code> to make it non-modal. 
   */
  public void setModal(boolean modal)
  {
    this.modal = modal;
  }

  /**
   * Tests whether or not this dialog box is resizable.
   * 
   * @return <code>true</code> if this dialog is resizable,
   * <code>false</code> otherwise.
   */
  public boolean isResizable()
  {
    return resizable;
  }

  /**
   * Changes the resizability of this dialog box.
   * 
   * @param resizable <code>true</code> to make this dialog resizable,
   * <code>false</code> to make it non-resizable.
   */
  public synchronized void setResizable(boolean resizable)
  {
    this.resizable = resizable;
    if (peer != null)
      {
        DialogPeer d = (DialogPeer) peer;
        d.setResizable(resizable);
      }
  }

  /**
   * Creates this object's native peer.
   */
  public synchronized void addNotify()
  {
    if (peer == null)
      peer = getToolkit().createDialog(this);
    super.addNotify();
  }

  /**
   * Makes this dialog visible and brings it to the front. If the dialog is
   * modal and is not already visible, this call will not return until the
   * dialog is hidden by someone calling hide or dispose. If this is the event
   * dispatching thread we must ensure that another event thread runs while the
   * one which invoked this method is blocked.
   * 
   * @deprecated Use {@link Component#setVisible(boolean)} instead.
   */
  public synchronized void show()
  {
    super.show();

    if (isModal())
      {
        // If already shown (and blocked) just return
        if (blocked)
          return;

        /*
         * If show is called in the dispatch thread for a modal dialog it will
         * block so we must run another thread so the events keep being
         * dispatched.
         */
        if (EventQueue.isDispatchThread())
          {
            EventQueue eq = Toolkit.getDefaultToolkit().getSystemEventQueue();
            eq2 = new EventQueue();
            eq.push(eq2);
          }

        try
          {
            blocked = true;
            wait();
            blocked = false;
          }
        catch (InterruptedException e)
          {
            blocked = false;
          }

        if (eq2 != null)
          {
            eq2.pop();
            eq2 = null;
          }
      }
  }

  /**
   * Hides the Dialog and then causes show() to return if it is currently
   * blocked.
   * 
   * @deprecated Use {@link Component#setVisible(boolean)} instead.
   */
  public synchronized void hide()
  {
    if (blocked)
      {
        notifyAll();
      }

    super.hide();
  }

  /**
   * Disposes the Dialog and then causes show() to return if it is currently
   * blocked.
   */
  public synchronized void dispose()
  {
    if (blocked)
      {
        notifyAll();
      }

    super.dispose();
  }

  /**
   * Returns a debugging string for this component.
   * 
   * @return A debugging string for this component.
   */
  protected String paramString()
  {
    return "title+" + title + ",modal=" + modal + ",resizable=" + resizable
            + "," + super.paramString();
  }

  /**
   * Returns whether this frame is undecorated or not.
   * 
   * @return <code>true</code> if this dialog is undecorated,
   * <code>false</code> otherwise.
   * 
   * @since 1.4
   */
  public boolean isUndecorated()
  {
    return undecorated;
  }

  /**
   * Disables or enables decorations for this frame. This method can only be
   * called while the frame is not displayable.
   * 
   * @param undecorated <code>true</code> to disable dialog decorations,
   * <code>false</code> otherwise.
   * 
   * @exception IllegalComponentStateException If this frame is displayable.
   * @since 1.4
   */
  public void setUndecorated(boolean undecorated)
  {
    if (isDisplayable())
      throw new IllegalComponentStateException();

    this.undecorated = undecorated;
  }

  /**
   * Accessibility support for <code>Dialog</code>.
   */
  protected class AccessibleAWTDialog
      extends AccessibleAWTWindow
  {
    private static final long serialVersionUID = 4837230331833941201L;

    /**
     * Gets the role of this object.
     * @return AccessibleRole.DIALOG 
     */
    public AccessibleRole getAccessibleRole()
    {
      return AccessibleRole.DIALOG;
    }

    /**
     * Gets the state set of this object.
     * @return The current state of this dialog.
     */
    public AccessibleStateSet getAccessibleStateSet()
    {
      AccessibleStateSet states = super.getAccessibleStateSet();
      if (isResizable())
        states.add(AccessibleState.RESIZABLE);
      if (isModal())
        states.add(AccessibleState.MODAL);
      return states;
    }
  }

  /**
   * Gets the AccessibleContext associated with this <code>Dialog</code>. The
   * context is created, if necessary.
   * 
   * @return the associated context
   */
  public AccessibleContext getAccessibleContext()
  {
    /* Create the context if this is the first request */
    if (accessibleContext == null)
      accessibleContext = new AccessibleAWTDialog();
    return accessibleContext;
  }

}