embeddedobj/test/Container1/NativeView.java

   1 /*
   2  * This file is part of the LibreOffice project.
   3  *
   4  * This Source Code Form is subject to the terms of the Mozilla Public
   5  * License, v. 2.0. If a copy of the MPL was not distributed with this
   6  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   7  *
   8  * This file incorporates work covered by the following license notice:
   9  *
  10  *   Licensed to the Apache Software Foundation (ASF) under one or more
  11  *   contributor license agreements. See the NOTICE file distributed
  12  *   with this work for additional information regarding copyright
  13  *   ownership. The ASF licenses this file to you under the Apache
  14  *   License, Version 2.0 (the "License"); you may not use this file
  15  *   except in compliance with the License. You may obtain a copy of
  16  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  17  */
  18 package embeddedobj.test;
  19
  20 // __________ Imports __________
  21
  22 import java.awt.*;
  23 import java.lang.*;
  24 import java.awt.event.*;
  25
  26 // __________ Implementation __________
  27
  28 /**
  29  * Class to pass the system window handle to the OpenOffice.org toolkit.
  30  * It use special JNI methods to get the system handle of used java window.
  31  *
  32  * Attention!
  33  * Use JNI functions on already visible canvas objects only!
  34  * Otherwise they can make some trouble.
  35  *
  36  */
  37
  38 public class NativeView extends java.awt.Canvas
  39 {
  40
  41
  42     /**
  43      * ctor
  44      * Does nothing really.
  45      * We can use our JNI mechanism for an already visible
  46      * canvas only. So we override the method for showing ( "setVisible()" )
  47      * and make our initialization there. BUt we try to show an empty clean
  48      * window till there.
  49      */
  50     public NativeView()
  51     {
  52         maHandle = null;
  53         maSystem = 0;
  54         this.setBackground( Color.white );
  55     }
  56
  57
  58
  59     /**
  60      * Override this method to make necessary initializations here.
  61      * ( e.g. get the window handle and necessary system information )
  62      *
  63      * Why here?
  64      * Because the handle seems to be available for already-visible windows
  65      * only. So it's the best place to get it. The special helper method
  66      * can be called more than once - but call native code one time only
  67      * and save the handle and the system type on our members maHandle/maSystem!
  68      */
  69     public void setVisible( boolean bState )
  70     {
  71         getHWND();
  72     }
  73
  74
  75
  76     /**
  77      * to guarantee right resize handling inside a swing container
  78      * ( e.g. JSplitPane ) we must provide some information about our
  79      * preferred/minimum and maximum size.
  80      */
  81     public Dimension getPreferredSize()
  82     {
  83         return new Dimension( 800, 600 );
  84     }
  85
  86     public Dimension getMaximumSize()
  87     {
  88         return new Dimension( 1024, 768 );
  89     }
  90
  91     public Dimension getMinimumSize()
  92     {
  93         return new Dimension( 300, 300 );
  94     }
  95
  96
  97
  98     /**
  99      * override paint routine to show provide against
 100      * repaint errors if no office view is really plugged
 101      * into this canvas.
 102      * If handle is present - we shouldn't paint anything further.
 103      * May the remote window is already plugged. In such case we
 104      * shouldn't paint it over.
 105      */
 106     public void paint( Graphics aGraphic )
 107     {
 108         if( maHandle == null )
 109         {
 110             Dimension aSize = getSize();
 111             aGraphic.clearRect( 0, 0, aSize.width, aSize.height );
 112         }
 113     }
 114
 115
 116
 117     /**
 118      * JNI interface of this class
 119      * These two methods are implemented by using JNI mechanismen.
 120      * The will be used to get the platform dependent window handle
 121      * of a java awt canvas. This handle can be used to create an office
 122      * window as direct child of it. So it's possible to plug Office
 123      * windows in a java UI container.
 124      *
 125      * Note:
 126      * Native code for Windows registers a special function pointer to handle
 127      * window messages... But if it doesn't check for an already-registered
 128      * instance of this handler it will do it twice and produce a stack overflow
 129      * because such method calls itself in a never-ending loop...
 130      * So we try to use the JNI code one time only and save already-obtained
 131      * information inside this class.
 132      */
 133     public  native int  getNativeWindowSystemType();
 134     private native long getNativeWindow(); // private! => use getHWND() with cache mechanism!
 135
 136     public Integer getHWND()
 137     {
 138         if( maHandle == null )
 139         {
 140             maHandle = Integer.valueOf( (int )getNativeWindow() );
 141             maSystem = getNativeWindowSystemType();
 142         }
 143         return maHandle;
 144     }
 145
 146
 147
 148     /**
 149      * for using of the JNI methods it's necessary to load
 150      * system library which exports it.
 151      */
 152     static
 153     {
 154         System.loadLibrary( "nativeview" );
 155     }
 156
 157
 158
 159     /**
 160      * @member  maHandle    system window handle
 161      * @member  maSystem    info about currently used platform
 162      */
 163     public Integer maHandle ;
 164     public int     maSystem ;
 165 }
 166