org.drools.compiler.compiler.xml.rules.ExistsHandler Maven / Gradle / Ivy

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/*
 * 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.compiler.xml.rules;

import org.drools.compiler.lang.descr.ConditionalElementDescr;
import org.drools.compiler.lang.descr.ExistsDescr;
import org.drools.compiler.lang.descr.PatternDescr;
import org.drools.core.xml.BaseAbstractHandler;
import org.drools.core.xml.ExtensibleXmlParser;
import org.drools.core.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 ExistsHandler extends BaseAbstractHandler
    implements
    Handler {
    public ExistsHandler() {
    }

    public Object start(final String uri,
                        final String localName,
                        final Attributes attrs,
                        final ExtensibleXmlParser parser) throws SAXException {
        parser.startElementBuilder( localName,
                                    attrs );
        final ExistsDescr existsDescr = new ExistsDescr();

        return existsDescr;
    }

    public Object end(final String uri,
                      final String localName,
                      final ExtensibleXmlParser parser) throws SAXException {
        final Element element = parser.endElementBuilder();

        final ExistsDescr existsDescr = (ExistsDescr) parser.getCurrent();

        if ( (existsDescr.getDescrs().size() != 1) && (existsDescr.getDescrs().get( 0 ).getClass() != PatternDescr.class) ) {
            throw new SAXParseException( " can only have a single  as a child element",
                                         parser.getLocator() );
        }

        final ConditionalElementDescr parentDescr = (ConditionalElementDescr) parser.getParent();
        parentDescr.addDescr( existsDescr );

        return existsDescr;
    }

    public Class generateNodeFor() {
        return ExistsDescr.class;
    }
}