/*
* Copyright 2010 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.core.base.dataproviders;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.Serializable;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import org.drools.core.WorkingMemory;
import org.drools.core.base.mvel.MVELCompilationUnit;
import org.drools.core.base.mvel.MVELCompileable;
import org.drools.core.common.InternalFactHandle;
import org.drools.core.common.InternalWorkingMemory;
import org.drools.core.reteoo.LeftTuple;
import org.drools.core.rule.Declaration;
import org.drools.core.rule.MVELDialectRuntimeData;
import org.drools.core.spi.DataProvider;
import org.drools.core.spi.PropagationContext;
import org.drools.core.spi.Tuple;
import org.drools.core.util.ArrayIterator;
import org.drools.core.util.MVELSafeHelper;
import org.mvel2.integration.VariableResolverFactory;
public class MVELDataProvider
implements
DataProvider,
MVELCompileable,
Externalizable {
private static final long serialVersionUID = 510l;
private MVELCompilationUnit unit;
private String id;
private Serializable expr;
public MVELDataProvider() {
}
public MVELDataProvider(final MVELCompilationUnit unit,
final String id) {
this.unit = unit;
this.id = id;
}
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
id = in.readUTF();
unit = (MVELCompilationUnit) in.readObject();
// expr = (Serializable)in.readObject();
// prototype = (DroolsMVELFactory)in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeUTF( id );
out.writeObject( unit );
// out.writeObject(expr);
// out.writeObject(prototype);
}
@SuppressWarnings("unchecked")
public void compile(MVELDialectRuntimeData runtimeData) {
expr = unit.getCompiledExpression( runtimeData );
// @TODO URGENT DO NOT FORGET!!!!
// Map previousDeclarations = this.unit.getFactory().getPreviousDeclarations();
// this.requiredDeclarations = (Declaration[]) previousDeclarations.values().toArray( new Declaration[previousDeclarations.size()] );
}
public Declaration[] getRequiredDeclarations() {
return this.unit.getPreviousDeclarations();
}
public void replaceDeclaration(Declaration declaration,
Declaration resolved) {
this.unit.replaceDeclaration( declaration,
resolved );
}
public Object createContext() {
return null;
}
public Iterator getResults(final Tuple tuple,
final WorkingMemory wm,
final PropagationContext ctx,
final Object executionContext) {
VariableResolverFactory factory = unit.getFactory( null, null, null, ( InternalFactHandle ) null, (LeftTuple) tuple, null, (InternalWorkingMemory) wm, wm.getGlobalResolver() );
//this.expression.
final Object result = MVELSafeHelper.getEvaluator().executeExpression( this.expr,
factory );
if ( result == null ) {
return Collections.EMPTY_LIST.iterator();
} else if ( result instanceof Collection ) {
return ((Collection) result).iterator();
} else if ( result instanceof Iterator ) {
return (Iterator) result;
} else if ( result.getClass().isArray() ) {
return new ArrayIterator( result );
} else {
return Collections.singletonList( result ).iterator();
}
}
public DataProvider clone() {
// not sure this is safe, but at this point we don't have a classloader
// reference to compile a new copy of the data provider. My require
// refactory later.
return this;
}
}