/******************************************************************************
* Copyright (c) 2014 Oracle
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Konstantin Komissarchik - initial implementation and ongoing maintenance
******************************************************************************/
package org.eclipse.sapphire.internal;
import org.eclipse.sapphire.Element;
import org.eclipse.sapphire.ElementProperty;
import org.eclipse.sapphire.Event;
import org.eclipse.sapphire.ImpliedElementProperty;
import org.eclipse.sapphire.Listener;
import org.eclipse.sapphire.LoggingService;
import org.eclipse.sapphire.PropertyDef;
import org.eclipse.sapphire.RequiredConstraintService;
import org.eclipse.sapphire.Sapphire;
import org.eclipse.sapphire.ValueProperty;
import org.eclipse.sapphire.modeling.annotations.Required;
import org.eclipse.sapphire.modeling.el.FailSafeFunction;
import org.eclipse.sapphire.modeling.el.Function;
import org.eclipse.sapphire.modeling.el.FunctionResult;
import org.eclipse.sapphire.modeling.el.Literal;
import org.eclipse.sapphire.modeling.el.ModelElementFunctionContext;
import org.eclipse.sapphire.modeling.el.parser.ExpressionLanguageParser;
import org.eclipse.sapphire.services.ServiceCondition;
import org.eclipse.sapphire.services.ServiceContext;
/**
* {@link RequiredConstraintService} implementation that derives its behavior from @{@link Required} annotation.
*
* @author <a href="mailto:konstantin.komissarchik@oracle.com">Konstantin Komissarchik</a>
*/
public final class DeclarativeRequiredConstraintService extends RequiredConstraintService
{
private FunctionResult functionResult;
@Override
protected void initRequiredConstraintService()
{
Function function;
final Required annotation = context( PropertyDef.class ).getAnnotation( Required.class );
if( annotation == null )
{
function = Literal.FALSE;
}
else
{
final String expr = annotation.value().trim();
if( expr.length() == 0 )
{
function = Literal.TRUE;
}
else
{
try
{
function = ExpressionLanguageParser.parse( expr );
function = FailSafeFunction.create( function, Boolean.class, false );
}
catch( Exception e )
{
Sapphire.service( LoggingService.class ).log( e );
function = Literal.FALSE;
}
}
}
final ModelElementFunctionContext context = new ModelElementFunctionContext( context( Element.class ) );
this.functionResult = function.evaluate( context );
final Listener listener = new Listener()
{
@Override
public void handle( final Event event )
{
refresh();
}
};
this.functionResult.attach( listener );
}
@Override
protected Boolean compute()
{
return (Boolean) this.functionResult.value();
}
@Override
public void dispose()
{
super.dispose();
if( this.functionResult != null )
{
try
{
this.functionResult.dispose();
}
catch( Exception e )
{
Sapphire.service( LoggingService.class ).log( e );
}
}
}
public static final class Condition extends ServiceCondition
{
@Override
public boolean applicable( final ServiceContext context )
{
final PropertyDef property = context.find( PropertyDef.class );
return ( property instanceof ValueProperty || ( property instanceof ElementProperty && ! ( property instanceof ImpliedElementProperty ) ) );
}
}
}