odk/examples/DevelopersGuide/Forms/TableCellTextBinding.java

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  30 import com.sun.star.uno.Type;
  31 import com.sun.star.uno.UnoRuntime;
  32 import com.sun.star.table.XCell;
  33 import com.sun.star.util.XModifyListener;
  34 import com.sun.star.beans.XPropertySet;
  35 import com.sun.star.text.XTextRange;
  36 import com.sun.star.form.binding.IncompatibleTypesException;
  37
  38 /** a value binding to be connected to a form control
  39
  40     This binding synchronizes the text contained in a table cell (which you must
  41     pass upon construction) to the text in an XBindableValue.
  42
  43     Well, in real it does not synchronize both directions. The ValueBinding
  44     service has not much room for own activity: It allows notification of changes
  45     in the own value, and it allows external instances to set the current value.
  46
  47     Note that we implement this binding as a separate thread, which is (more or
  48     less permanently) polling for a new text at the cell. This is unfortunate, but
  49     sadly the Writer table cells do not support actively notifying changes in their
  50     content to other interested parties.
  51 */
  52 public class TableCellTextBinding
  53                 extends     java.lang.Thread
  54                 implements  com.sun.star.form.binding.XValueBinding,
  55                             com.sun.star.util.XModifyBroadcaster
  56 {
  57     private XTextRange  m_cellText;
  58     private Object      m_writeSignal;
  59     private String      m_newCellText;
  60     private String      m_lastKnownCellText;
  61     private boolean     m_haveNewCellText;
  62     private java.util.List  m_listeners;
  63
  64     /** Creates a new instance of TableCellTextBinding */
  65     public TableCellTextBinding( XCell cell )
  66     {
  67         m_cellText = (XTextRange)UnoRuntime.queryInterface( XTextRange.class, cell );
  68
  69         m_newCellText = new String();
  70         m_listeners = new java.util.LinkedList();
  71
  72         start();
  73     }
  74
  75     /** retrieves the list of data types which this binding can exchange
  76     */
  77     public com.sun.star.uno.Type[] getSupportedValueTypes()
  78     {
  79         try
  80         {
  81             // well, only strings here ...
  82             return new Type[] {
  83                 getStringType()
  84             };
  85         }
  86         catch( java.lang.Exception e )
  87         {
  88         }
  89         return new Type[] { };
  90     }
  91
  92     /** retrieves the current value
  93     */
  94     public Object getValue(com.sun.star.uno.Type type) throws com.sun.star.form.binding.IncompatibleTypesException
  95     {
  96         if ( !type.equals( getStringType() ) )
  97             throw new com.sun.star.form.binding.IncompatibleTypesException();
  98
  99         return m_cellText.getString();
 100     }
 101
 102     /** sets a new value
 103     */
 104     public void setValue(Object obj) throws com.sun.star.form.binding.IncompatibleTypesException
 105     {
 106         String text;
 107         try
 108         {
 109             text = (String)obj;
 110         }
 111         catch( java.lang.ClassCastException e )
 112         {
 113             throw new com.sun.star.form.binding.IncompatibleTypesException();
 114         }
 115         // remember the new text
 116         synchronized( m_newCellText )
 117         {
 118             m_newCellText = text;
 119             m_haveNewCellText = true;
 120         }
 121         // and wake up the thread which is waiting for it
 122         synchronized( m_writeSignal )
 123         {
 124             m_writeSignal.notify();
 125         }
 126     }
 127
 128     /** determines whether a given value type is supported
 129     */
 130     public boolean supportsType(com.sun.star.uno.Type type)
 131     {
 132         return type.equals( getStringType() );
 133     }
 134
 135     /** retrieves the UNO type for the string class
 136     */
 137     private static final Type getStringType()
 138     {
 139         return new com.sun.star.uno.Type( String.class );
 140     }
 141
 142     /** runs the thread
 143     */
 144     public void run()
 145     {
 146         try
 147         {
 148             m_writeSignal = new Object();
 149             while ( true )
 150             {
 151                 // go sleep a while
 152                 synchronized( m_writeSignal )
 153                 {
 154                     m_writeSignal.wait( 200 );
 155                 }
 156
 157                 // if there's new text in the control, propagate it to the cell
 158                 synchronized ( m_newCellText )
 159                 {
 160                     if ( m_haveNewCellText )
 161                     {
 162                         m_cellText.setString( m_newCellText );
 163                         m_lastKnownCellText = m_newCellText;
 164                     }
 165                     m_haveNewCellText = false;
 166                 }
 167
 168                 // if there's new text in the cell, propagate it to the control
 169                 String currentCellText = m_cellText.getString();
 170                 if ( !currentCellText.equals( m_lastKnownCellText ) )
 171                 {
 172                     m_lastKnownCellText = currentCellText;
 173                     // notify the modification
 174                     synchronized( m_listeners )
 175                     {
 176                         com.sun.star.lang.EventObject eventSource = new com.sun.star.lang.EventObject( this );
 177
 178                         java.util.Iterator loop = m_listeners.iterator();
 179                         while ( loop.hasNext() )
 180                         {
 181                             ((XModifyListener)loop.next()).modified( eventSource );
 182                         }
 183                     }
 184                 }
 185             }
 186         }
 187         catch( java.lang.Exception e )
 188         {
 189             e.printStackTrace(System.err);
 190         }
 191     }
 192
 193     public void addModifyListener(com.sun.star.util.XModifyListener xModifyListener)
 194     {
 195         synchronized( m_listeners )
 196         {
 197             m_listeners.add( xModifyListener );
 198         }
 199     }
 200
 201     public void removeModifyListener(com.sun.star.util.XModifyListener xModifyListener)
 202     {
 203         synchronized( m_listeners )
 204         {
 205             m_listeners.remove( xModifyListener );
 206         }
 207     }
 208
 209     public void disposing(com.sun.star.lang.EventObject eventObject)
 210     {
 211         // not interested in
 212     }
 213 }