package org.drools.rule.builder;
import org.drools.base.ArrayElements;
import org.drools.base.ClassObjectType;
import org.drools.base.DroolsQuery;
import org.drools.base.FieldFactory;
import org.drools.base.ValueType;
import org.drools.base.evaluators.Operator;
import org.drools.base.extractors.ArrayElementReader;
import org.drools.compiler.DescrBuildError;
import org.drools.lang.descr.QueryDescr;
import org.drools.rule.Declaration;
import org.drools.rule.LiteralConstraint;
import org.drools.rule.Pattern;
import org.drools.rule.Query;
import org.drools.spi.FieldValue;
import org.drools.spi.InternalReadAccessor;
import org.drools.spi.ObjectType;
public class QueryBuilder implements EngineElementBuilder {
public Pattern build(final RuleBuildContext context,
final QueryDescr queryDescr) {
ObjectType queryObjectType = ClassObjectType.DroolsQuery_ObjectType;
final Pattern pattern = new Pattern( context.getNextPatternId(),
0, // offset is 0 by default
queryObjectType,
null );
final InternalReadAccessor extractor = PatternBuilder.getFieldReadAccessor( context, queryDescr, queryObjectType, "name", null, true );
final FieldValue field = FieldFactory.getFieldValue( queryDescr.getName(),
ValueType.STRING_TYPE,
context.getPackageBuilder().getDateFormats() );
final LiteralConstraint constraint = new LiteralConstraint( extractor,
context.getConfiguration().getEvaluatorRegistry().getEvaluator( ValueType.STRING_TYPE,
Operator.EQUAL ),
field );
PatternBuilder.registerReadAccessor( context, queryObjectType, "name", constraint );
// adds appropriate constraint to the pattern
pattern.addConstraint( constraint );
ObjectType argsObjectType = new ClassObjectType( ArrayElements.class );
InternalReadAccessor arrayExtractor = PatternBuilder.getFieldReadAccessor( context, queryDescr, argsObjectType, "elements", null, true );
String[] params = queryDescr.getParameters();
String[] types = queryDescr.getParameterTypes();
int i = 0;
Declaration[] declarations = new Declaration[ params.length ];
try {
for ( i = 0; i < params.length; i++ ) {
Declaration declr = pattern.addDeclaration( params[i] );
// this bit is different, notice its the ArrayElementReader that we wire up to, not the declaration.
ArrayElementReader reader = new ArrayElementReader( arrayExtractor,
i,
context.getDialect().getTypeResolver().resolveType( types[i] ) );
PatternBuilder.registerReadAccessor( context, argsObjectType, "elements", reader );
declr.setReadAccessor( reader );
declarations[i] = declr;
}
((Query)context.getRule()).setParameters( declarations );
} catch ( ClassNotFoundException e ) {
context.getErrors().add( new DescrBuildError( context.getParentDescr(),
queryDescr,
e,
"Unable to resolve type '" + types[i] + " for parameter" + params[i] ) );
}
return pattern;
}
}