/*
* Copyright 2005 JBoss Inc
*
* Licensed 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 under the License.
*/
package org.drools.compiler.xml.rules;
import java.util.HashSet;
import org.drools.lang.descr.BindingDescr;
import org.drools.lang.descr.ExprConstraintDescr;
import org.drools.lang.descr.FieldConstraintDescr;
import org.drools.lang.descr.PatternDescr;
import org.drools.lang.descr.PredicateDescr;
import org.drools.xml.BaseAbstractHandler;
import org.drools.xml.ExtensibleXmlParser;
import org.drools.xml.Handler;
import org.w3c.dom.Element;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
/**
*
* TODO To change the template for this generated type comment go to Window -
* Preferences - Java - Code Style - Code Templates
*/
public class PredicateHandler extends BaseAbstractHandler
implements
Handler {
public PredicateHandler() {
}
public Object start(final String uri,
final String localName,
final Attributes attrs,
final ExtensibleXmlParser parser) throws SAXException {
parser.startElementBuilder( localName,
attrs );
return ""; // need to return something, otherwise it'll pop the parent
}
public Object end(final String uri,
final String localName,
final ExtensibleXmlParser parser) throws SAXException {
final Element element = parser.endElementBuilder();
final String expression =((org.w3c.dom.Text)element.getChildNodes().item( 0 )).getWholeText();
if ( expression == null || expression.trim().equals( "" ) ) {
throw new SAXParseException( "<predicate> must have some content",
parser.getLocator() );
}
final PatternDescr patternDescr = (PatternDescr) parser.getParent();
ExprConstraintDescr expr = new ExprConstraintDescr("eval(" + expression + ")");
patternDescr.addConstraint( expr );
return expr;
}
public Class generateNodeFor() {
return PredicateDescr.class;
}
}