/*! ******************************************************************************
*
* Pentaho Data Integration
*
* Copyright (C) 2002-2013 by Pentaho : http://www.pentaho.com
*
*******************************************************************************
*
* 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.
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package org.pentaho.di.trans.steps.rules;
import java.io.StringReader;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseFactory;
import org.drools.builder.KnowledgeBuilder;
import org.drools.builder.KnowledgeBuilderFactory;
import org.drools.builder.ResourceType;
import org.drools.definition.KnowledgePackage;
import org.drools.io.Resource;
import org.drools.io.ResourceFactory;
import org.drools.runtime.ObjectFilter;
import org.drools.runtime.StatefulKnowledgeSession;
import org.pentaho.di.core.row.RowMetaInterface;
import org.pentaho.di.core.row.ValueMetaInterface;
import org.pentaho.di.i18n.BaseMessages;
import org.pentaho.di.trans.step.BaseStepData;
import org.pentaho.di.trans.step.StepDataInterface;
import org.pentaho.di.trans.steps.rules.Rules.Column;
/**
* This Transformation Step allows a user to execute a rule set against an individual rule or a collection of rules.
*
* Additional columns can be added to the output from the rules and these (of course) can be used for routing if
* desired.
*
* @author cboyden
*
*/
public class RulesExecutorData extends BaseStepData implements StepDataInterface {
private static Class<?> PKG = RulesExecutor.class; // for i18n purposes
private RowMetaInterface outputRowMeta;
private KnowledgeBuilder kbuilder;
private KnowledgeBase kbase;
private Column[] columnList;
private Map<String, Column> resultMap = new HashMap<String, Column>();
private String ruleString;
public String getRuleString() {
return ruleString;
}
public void setRuleString( String ruleString ) {
this.ruleString = ruleString;
}
public String getRuleFilePath() {
return ruleFilePath;
}
public void setRuleFilePath( String ruleFilePath ) {
this.ruleFilePath = ruleFilePath;
}
private String ruleFilePath;
public void setOutputRowMeta( RowMetaInterface outputRowMeta ) {
this.outputRowMeta = outputRowMeta;
}
public RowMetaInterface getOutputRowMeta() {
return outputRowMeta;
}
public void initializeRules() {
// To ensure the plugin classloader use for dependency resolution
ClassLoader orig = Thread.currentThread().getContextClassLoader();
ClassLoader loader = getClass().getClassLoader();
Thread.currentThread().setContextClassLoader( loader );
Resource ruleSet = null;
if ( ruleString != null ) {
ruleSet = ResourceFactory.newReaderResource( new StringReader( ruleString ) );
} else {
ruleSet = ResourceFactory.newFileResource( ruleFilePath );
}
kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
kbuilder.add( ruleSet, ResourceType.DRL );
if ( kbuilder.hasErrors() ) {
System.out.println( kbuilder.getErrors().toString() );
throw new RuntimeException( BaseMessages.getString( PKG, "RulesData.Error.CompileDRL" ) );
}
Collection<KnowledgePackage> pkgs = kbuilder.getKnowledgePackages();
kbase = KnowledgeBaseFactory.newKnowledgeBase();
// Cache the knowledge base as its creation is intensive
kbase.addKnowledgePackages( pkgs );
// reset classloader back to original
Thread.currentThread().setContextClassLoader( orig );
}
public void initializeColumns( RowMetaInterface inputRowMeta ) {
if ( inputRowMeta == null ) {
BaseMessages.getString( PKG, "RulesData.InitializeColumns.InputRowMetaIsNull" );
return;
}
// Create objects for insertion into the rules engine
List<ValueMetaInterface> columns = inputRowMeta.getValueMetaList();
// This array must 1-1 match the row[] feteched by getRow()
columnList = new Column[columns.size()];
for ( int i = 0; i < columns.size(); i++ ) {
ValueMetaInterface column = columns.get( i );
Column c = new Column( true );
c.setName( column.getName() );
c.setType( column.getTypeDesc() );
c.setPayload( null );
columnList[i] = c;
}
}
public void loadRow( Object[] r ) {
for ( int i = 0; i < columnList.length; i++ ) {
columnList[i].setPayload( r[i] );
}
resultMap.clear();
}
public void execute() {
StatefulKnowledgeSession session = initNewKnowledgeSession();
Collection<Object> oList = fetchColumns( session );
for ( Object o : oList ) {
resultMap.put( ( (Column) o ).getName(), (Column) o );
}
session.dispose();
}
protected StatefulKnowledgeSession initNewKnowledgeSession() {
StatefulKnowledgeSession session = kbase.newStatefulKnowledgeSession();
for ( int i = 0; i < columnList.length; i++ ) {
session.insert( columnList[i] );
}
session.fireAllRules();
return session;
}
protected Collection<Object> fetchColumns( StatefulKnowledgeSession session ) {
Collection<Object> oList = session.getObjects( new ObjectFilter() {
@Override
public boolean accept( Object o ) {
if ( o instanceof Column && !( (Column) o ).isExternalSource() ) {
return true;
}
return false;
}
} );
return oList;
}
/**
*
* @param columnName
* Column.payload associated with the result, or null if not found
* @return
*/
public Object fetchResult( String columnName ) {
return resultMap.get( columnName );
}
public void shutdown() {
}
}