/*
* 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.template.parser;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.mvel2.integration.VariableResolverFactory;
import org.mvel2.integration.impl.MapVariableResolverFactory;
import org.mvel2.templates.CompiledTemplate;
import org.mvel2.templates.SimpleTemplateRegistry;
import org.mvel2.templates.TemplateCompiler;
import org.mvel2.templates.TemplateRegistry;
import org.mvel2.templates.TemplateRuntime;
/**
* Generate the rules for a decision table row from a rule template.
*/
public class DefaultGenerator
implements
Generator {
private Map<String, RuleTemplate> ruleTemplates;
private TemplateRegistry registry = new SimpleTemplateRegistry();
private List<String> rules = new ArrayList<String>();
public DefaultGenerator( final Map<String, RuleTemplate> t ) {
ruleTemplates = t;
}
/*
* (non-Javadoc)
*
* @see org.kie.decisiontable.parser.Generator#generate(java.lang.String,
* org.kie.decisiontable.parser.Row)
*/
public void generate( String templateName,
Row row ) {
try {
CompiledTemplate template = getTemplate( templateName );
VariableResolverFactory factory = new MapVariableResolverFactory();
Map<String, Object> vars = new HashMap<String, Object>();
initializePriorCommaConstraints( vars );
initializeHasPriorJunctionConstraint( vars );
vars.put( "row",
row );
for ( Cell cell : row.getCells() ) {
cell.addValue( vars );
}
String drl = String.valueOf( TemplateRuntime.execute( template,
vars,
factory,
registry ) );
rules.add( drl );
} catch ( Exception e ) {
throw new RuntimeException( e );
}
}
private void initializePriorCommaConstraints( final Map<String, Object> vars ) {
for ( int depth = 0; depth < 10; depth++ ) {
vars.put( "hasPriorCommaConstraint" + depth,
false );
}
}
private void initializeHasPriorJunctionConstraint( final Map<String, Object> vars ) {
for ( int depth = 0; depth < 10; depth++ ) {
vars.put( "hasPriorJunctionConstraint" + depth,
false );
}
}
private CompiledTemplate getTemplate( String templateName ) throws IOException {
CompiledTemplate contents;
if ( !registry.contains( templateName ) ) {
RuleTemplate template = ruleTemplates.get( templateName );
contents = TemplateCompiler.compileTemplate( template.getContents() );
registry.addNamedTemplate( templateName,
contents );
} else {
contents = registry.getNamedTemplate( templateName );
}
return contents;
}
/*
* (non-Javadoc)
*
* @see org.kie.decisiontable.parser.Generator#getDrl()
*/
public String getDrl() {
StringBuffer sb = new StringBuffer();
for ( String rule : rules ) {
sb.append( rule ).append( "\n" );
}
return sb.toString();
}
}