AOO410/main/odk/examples/DevelopersGuide/Forms/GridFieldValidator.java

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 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
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/**************************************************************************/
import com.sun.star.uno.*;
import com.sun.star.beans.*;
import com.sun.star.form.*;
import com.sun.star.lang.*;
import com.sun.star.sdb.*;
import com.sun.star.sdbc.*;
import com.sun.star.sdbcx.*;
import com.sun.star.container.*;
import com.sun.star.awt.*;
import com.sun.star.task.*;

/**************************************************************************/
/** helper class for validating a grid field before it is updated

	<p>Actually, the mechanism for validating the field is not restricted to
	grid control fields. Instead, it can be used for any bound controls.</p>
*/
class GridFieldValidator implements XUpdateListener
{
	private DocumentHelper		m_aDocument;
	private	XComponentContext	m_xCtx;
	private XPropertySet		m_xWatchedColumn;

	private	boolean			m_bWatching;

	/* ------------------------------------------------------------------ */
	public GridFieldValidator( XComponentContext xCtx, XPropertySet xWatchedGridColumn )
	{
		// remember
		m_xCtx = xCtx;
		m_xWatchedColumn = xWatchedGridColumn;
		m_aDocument = DocumentHelper.getDocumentForComponent(xWatchedGridColumn,
                                                             xCtx);

		m_bWatching = false;
	}

	/* ------------------------------------------------------------------ */
	public void enableColumnWatch( boolean bEnable )
	{
		if ( bEnable == m_bWatching )
			return;

		XUpdateBroadcaster xUpdate = (XUpdateBroadcaster)UnoRuntime.queryInterface(
			XUpdateBroadcaster.class, m_xWatchedColumn );

		if ( bEnable )
			xUpdate.addUpdateListener( this );
		else
			xUpdate.removeUpdateListener( this );

		m_bWatching = bEnable;
	}

	/* ------------------------------------------------------------------ */
	/** shows a message that we can't do several things due to an implementation error
	*/
	private void showInvalidValueMessage( )
	{
		try
		{
			// build the message we want to show
			String sMessage = "The column \"";
			sMessage += FLTools.getLabel( m_xWatchedColumn );
			sMessage += "\" is not allowed to contain empty strings.";

			SQLContext aError = new SQLContext(
				new String( "Invalid Value Entered" ),
				null,
				new String( "S1000" ),
				0,
				new Any( new Type(), null ),
				sMessage
			);

			// instantiate an interaction handler who can handle SQLExceptions
			XInteractionHandler xHandler = (XInteractionHandler)UnoRuntime.queryInterface(
				XInteractionHandler.class,
                m_xCtx.getServiceManager().createInstanceWithContext(
                    "com.sun.star.task.InteractionHandler", m_xCtx ) );

			// create a new request and execute it
			InteractionRequest aRequest = new InteractionRequest( aError );
			xHandler.handle( aRequest );
		}
		catch( com.sun.star.uno.Exception e )
		{
			System.out.println(e);
			e.printStackTrace();
		}
	}

	/* ------------------------------------------------------------------ */
	// XUpdateListener overridables
	/* ------------------------------------------------------------------ */
    public boolean approveUpdate( EventObject aEvent ) throws com.sun.star.uno.RuntimeException
	{
		boolean bApproved = true;
		try
		{
			// the control model which fired the event
			XPropertySet xSourceProps = UNO.queryPropertySet( aEvent.Source );

			String sNewText = (String)xSourceProps.getPropertyValue( "Text" );
			if ( 0 == sNewText.length() )
			{
				// say that the value is invalid
				showInvalidValueMessage( );
				bApproved = false;

				// reset the control value
				// for this, we take the current value from the row set field the control
				// is bound to, and forward it to the control model
				XColumn xBoundColumn = UNO.queryColumn( xSourceProps.getPropertyValue( "BoundField" ) );
				if ( null != xBoundColumn )
				{
					xSourceProps.setPropertyValue( "Text", xBoundColumn.getString() );
				}
			}
		}
		catch( com.sun.star.uno.Exception e )
		{
			System.out.println(e);
			e.printStackTrace();
		}
		return bApproved;
	}

	/* ------------------------------------------------------------------ */
    public void updated( EventObject aEvent ) throws com.sun.star.uno.RuntimeException
	{
	}

	/* ------------------------------------------------------------------ */
	// XEventListener overridables
	/* ------------------------------------------------------------------ */
	public void disposing( EventObject aEvent )
	{
		// not interested in
	}
};