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From Andrus Adamchik <and...@objectstyle.org>
Subject Re: Is andExp supported on Scalar booleans?
Date Thu, 17 Aug 2006 13:52:36 GMT
Good point. Another suggestion: instead of using ASTScalar, you can  
implement a similar custom subclass that extends ConditionNode. E.g.  
"ASTBoolean extends ASTCondition".

We should include this in Cayenne at some point too...

Andrus


On Aug 16, 2006, at 4:47 PM, Øyvind Harboe wrote:

> I'm getting an exception when I try to invoke andExp() on a Scalar  
> expression:
>
> Expression e=new ASTScalar(Boolean.TRUE);
> e=e.andExp(ExpressionFactory.matchExp(propName + (i+1), t));
>
> [v.1.2-dev July 19 2006] And: invalid child - Scalar
> org.objectstyle.cayenne.exp.parser.AggregateConditionNode.jjtAddChild( 
> AggregateConditionNode.java:125)
> org.objectstyle.cayenne.exp.parser.SimpleNode.setOperand 
> (SimpleNode.java:187)
> org.objectstyle.cayenne.exp.Expression.joinExp(Expression.java:395)
> org.objectstyle.cayenne.exp.Expression.andExp(Expression.java:405)
>
> Some fiendishly clever code to work around horrid database structures
> for implementing trees:
>
> 	/* returns the non-recursive list of children based upon the old
> scheme for trees */
> 	public Expression getChildrenQualifierGeneric(
> 			/* Name of property without the number suffix, e.g.  
> "treataspecVc" */
> 			String propName,
> 			/* total number of levels, for e.g. treataspecVc==5 */
> 			int totLevels)
> 	{
> 		try
> 		{
> 			OgnlContext context = new OgnlContext();
> 			Expression e=new ASTScalar(Boolean.TRUE);
> 			
> 			for (int i=0; i<totLevels; i++)
> 			{
> 				Object propObj;
> 				propObj = Ognl.parseExpression(propName + (i+1));
> 				String t=(String) Ognl.getValue(propObj, context, this);
> 				if (t==null)
> 				{
> 					e=e.andExp(ExpressionFactory.noMatchExp(propName + (i+1), null));
> 					e=e.andExp(ExpressionFactory.matchExp(propName + (i+2), null));
> 					return e;
> 				} else if ((i+1)<totLevels)
> 				{
> 					e=e.andExp(ExpressionFactory.matchExp(propName + (i+1), t));
> 				}
> 			}
> 			return new ASTScalar(Boolean.FALSE);
> 		} catch (OgnlException e)
> 		{
> 			throw new RuntimeException(e);
> 		}
> 	}
>
>
> -- 
> Øyvind Harboe
> http://www.zylin.com
>


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