/*
* Copyright 2006 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.rule.builder;
import java.util.Iterator;
import org.drools.core.RuntimeDroolsException;
import org.drools.compiler.lang.descr.AndDescr;
import org.drools.compiler.lang.descr.BaseDescr;
import org.drools.compiler.lang.descr.ConditionalElementDescr;
import org.drools.compiler.lang.descr.ExistsDescr;
import org.drools.compiler.lang.descr.NotDescr;
import org.drools.compiler.lang.descr.OrDescr;
import org.drools.core.rule.GroupElement;
import org.drools.core.rule.GroupElementFactory;
import org.drools.core.rule.Pattern;
import org.drools.core.rule.RuleConditionElement;
public class GroupElementBuilder
implements
RuleConditionBuilder {
public RuleConditionElement build(final RuleBuildContext context,
final BaseDescr descr) {
return build( context,
descr,
null );
}
public RuleConditionElement build(final RuleBuildContext context,
final BaseDescr descr,
final Pattern prefixPattern) {
final ConditionalElementDescr cedescr = (ConditionalElementDescr) descr;
final GroupElement ge = this.newGroupElementFor( descr );
context.getBuildStack().push( ge );
if ( prefixPattern != null ) {
ge.addChild( prefixPattern );
}
// iterate over child descriptors
for ( final Iterator it = cedescr.getDescrs().iterator(); it.hasNext(); ) {
// gets child to build
final BaseDescr child = (BaseDescr) it.next();
child.setResource(context.getRuleDescr().getResource());
child.setNamespace(context.getRuleDescr().getNamespace());
// gets corresponding builder
final RuleConditionBuilder builder = (RuleConditionBuilder) context.getDialect().getBuilder( child.getClass() );
if ( builder != null ) {
final RuleConditionElement element = builder.build( context,
child );
// in case there is a problem with the building,
// builder will return null. Ex: ClassNotFound for the pattern type
if ( element != null ) {
ge.addChild( element );
}
} else {
throw new RuntimeDroolsException( "BUG: no builder found for descriptor class " + child.getClass() );
}
}
context.getBuildStack().pop();
return ge;
}
protected GroupElement newGroupElementFor( final BaseDescr baseDescr ) {
Class descr = baseDescr.getClass();
if ( AndDescr.class.isAssignableFrom( descr ) ) {
return GroupElementFactory.newAndInstance();
} else if ( OrDescr.class.isAssignableFrom( descr ) ) {
return GroupElementFactory.newOrInstance();
} else if ( NotDescr.class.isAssignableFrom( descr ) ) {
return GroupElementFactory.newNotInstance();
} else if ( ExistsDescr.class.isAssignableFrom( descr ) ) {
return GroupElementFactory.newExistsInstance();
} else {
throw new RuntimeDroolsException( "BUG: Not able to create a group element for descriptor: " + descr.getName() );
}
}
}