odk/examples/DevelopersGuide/Forms/ControlLock.java

   1 /*************************************************************************
   2  *
   3  *  $RCSfile: ControlLock.java,v $
   4  *
   5  *  $Revision: 1.4 $
   6  *
   7  *  last change: $Author: rt $ $Date: 2005-01-31 16:28:13 $
   8  *
   9  *  The Contents of this file are made available subject to the terms of
  10  *  the BSD license.
  11  *
  12  *  Copyright (c) 2003 by Sun Microsystems, Inc.
  13  *  All rights reserved.
  14  *
  15  *  Redistribution and use in source and binary forms, with or without
  16  *  modification, are permitted provided that the following conditions
  17  *  are met:
  18  *  1. Redistributions of source code must retain the above copyright
  19  *     notice, this list of conditions and the following disclaimer.
  20  *  2. Redistributions in binary form must reproduce the above copyright
  21  *     notice, this list of conditions and the following disclaimer in the
  22  *     documentation and/or other materials provided with the distribution.
  23  *  3. Neither the name of Sun Microsystems, Inc. nor the names of its
  24  *     contributors may be used to endorse or promote products derived
  25  *     from this software without specific prior written permission.
  26  *
  27  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30  *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31  *  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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  37  *  USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  38  *
  39  *************************************************************************/
  40
  41 import com.sun.star.uno.*;
  42 import com.sun.star.lang.*;
  43 import com.sun.star.container.*;
  44 import com.sun.star.beans.*;
  45 import com.sun.star.form.*;
  46 import com.sun.star.util.*;
  47 import com.sun.star.sdbc.*;
  48
  49
  50 /**************************************************************************/
  51 /** A helper class for recursively locking control models which are bound
  52     to a specific field
  53 */
  54
  55 class LockControlModels extends ComponentTreeTraversal
  56 {
  57     private String      m_sDataField;
  58     private Boolean     m_aLockIt;
  59     private int         m_nLevel;       // nesting level relative to the form we started with
  60
  61     /* ------------------------------------------------------------------ */
  62     public LockControlModels( String sDataField, boolean bLockIt )
  63     {
  64         m_sDataField = sDataField;
  65         m_aLockIt = new Boolean( bLockIt );
  66         m_nLevel = 0;
  67     }
  68
  69     /* ------------------------------------------------------------------ */
  70     protected boolean shouldStepInto( XIndexContainer xContainer ) throws com.sun.star.uno.Exception
  71     {
  72         if ( !super.shouldStepInto( xContainer ) )
  73             return false;       // don't try to be more clever than our base class
  74
  75         XForm xForm = (XForm)UnoRuntime.queryInterface( XForm.class, xContainer );
  76         if ( ( null != xForm ) && ( m_nLevel > 1 ) )
  77             // don't step into sub forms - we only handle the form we were originally
  78             // applied to
  79             return false;
  80
  81         return true;
  82     }
  83
  84     /* ------------------------------------------------------------------ */
  85     public void handle( Object aFormComponent ) throws com.sun.star.uno.Exception
  86     {
  87         // entering this nesting level
  88         ++m_nLevel;
  89
  90         // check if the component has a DataField property
  91         XPropertySet xCompProps = UNO.queryPropertySet( aFormComponent );
  92         XPropertySetInfo xPSI = null;
  93         if ( null != xCompProps )
  94             xPSI = xCompProps.getPropertySetInfo();
  95
  96         if ( ( null != xPSI ) && xPSI.hasPropertyByName( "DataField" ) )
  97         {       // indeed it has ....
  98             String sDataField = (String)xCompProps.getPropertyValue( "DataField" );
  99             if ( sDataField.equals( m_sDataField ) )
 100             {   // we found a control model which is bound to what we're looking for
 101                 xCompProps.setPropertyValue( "ReadOnly", m_aLockIt );
 102             }
 103         }
 104
 105         // allow the super class to step down, if possible
 106         super.handle( aFormComponent );
 107
 108         // leaving this nesting level
 109         --m_nLevel;
 110     }
 111 };
 112
 113 /**************************************************************************/
 114 /** a class which automatically handles control locking.
 115     <p>The class has to be bound to a form. Upon every movement of the form,
 116     all controls which are bound to a (to be specified) field are locked
 117     on existing and unlocked on new records.</p>
 118 */
 119 class ControlLock implements XRowSetListener
 120 {
 121     private     XPropertySet    m_xForm;
 122     private     String                  m_sDataField;
 123     private boolean                     m_bLockingEnabled;
 124     private boolean                     m_bPreviousRoundLock;
 125
 126     /* ------------------------------------------------------------------ */
 127     ControlLock( XPropertySet xForm, String sBoundDataField )
 128     {
 129         m_xForm = xForm;
 130         m_sDataField = sBoundDataField;
 131         m_bLockingEnabled = false;
 132         m_bPreviousRoundLock = false;
 133     }
 134
 135     /* ------------------------------------------------------------------ */
 136     /** updates the locks on the affected controls
 137     */
 138     protected void updateLocks( )
 139     {
 140         try
 141         {
 142             // first determine if we need to lock
 143             Boolean aIsNewRecord = (Boolean)m_xForm.getPropertyValue( "IsNew" );
 144
 145             boolean bNeedLock = m_bLockingEnabled && !aIsNewRecord.booleanValue();
 146
 147             if ( m_bPreviousRoundLock != bNeedLock )
 148             {
 149                 LockControlModels aLocker = new LockControlModels( m_sDataField, bNeedLock );
 150                 aLocker.handle( m_xForm );
 151                 m_bPreviousRoundLock = bNeedLock;
 152             }
 153
 154             // please note that we choose the expensive way here: We always loop through
 155             // _all_ control models belonging to the form. This clearly slows down the
 156             // whole process.
 157             // A better solution would be to cache the affected control models. Then we
 158             // could either rely on the fact that the model hierarchy is static, or we
 159             // could add ourself as container listener to the form.
 160         }
 161         catch(com.sun.star.uno.Exception e)
 162         {
 163             System.out.println(e);
 164             e.printStackTrace();
 165         }
 166     }
 167
 168     /* ------------------------------------------------------------------ */
 169     /** enables the locking in general
 170         <p>If the control models are really locked depends on the current
 171         record of the form: on the insert row, controls are never locked.</p>
 172     */
 173     public void enableLock( boolean bLock )
 174     {
 175         // remember this new setting
 176         m_bLockingEnabled = bLock;
 177
 178         // add or remove ourself as listener to get notified of cursor moves
 179         XRowSet xRowSet = (XRowSet)UnoRuntime.queryInterface(
 180             XRowSet.class, m_xForm );
 181         if ( m_bLockingEnabled )
 182         {
 183             xRowSet.addRowSetListener( this );
 184         }
 185         else
 186         {
 187             xRowSet.removeRowSetListener( this );
 188         }
 189
 190         // update the locks
 191         updateLocks();
 192     }
 193
 194     /* ==================================================================
 195        = UNO callbacks
 196        ================================================================== */
 197
 198     /* ------------------------------------------------------------------ */
 199     // XResetListener overridables
 200     /* ------------------------------------------------------------------ */
 201     public void cursorMoved( EventObject aEvent ) throws com.sun.star.uno.RuntimeException
 202     {
 203         updateLocks( );
 204     }
 205
 206     /* ------------------------------------------------------------------ */
 207     public void rowChanged( EventObject aEvent ) throws com.sun.star.uno.RuntimeException
 208     {
 209         // not interested in
 210     }
 211
 212     /* ------------------------------------------------------------------ */
 213     public void rowSetChanged( EventObject aEvent ) throws com.sun.star.uno.RuntimeException
 214     {
 215         // not interested in
 216     }
 217
 218     /* ------------------------------------------------------------------ */
 219     // XEventListener overridables
 220     /* ------------------------------------------------------------------ */
 221     public void disposing( EventObject aEvent )
 222     {
 223         // not interested in
 224     }
 225 }