/**
* 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.base.accumulators;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import org.drools.WorkingMemory;
import org.drools.base.mvel.DroolsMVELFactory;
import org.drools.base.mvel.MVELCompilationUnit;
import org.drools.base.mvel.MVELCompileable;
import org.drools.common.InternalFactHandle;
import org.drools.rule.Declaration;
import org.drools.spi.Accumulator;
import org.drools.spi.Tuple;
import org.mvel2.MVEL;
/**
* An MVEL accumulator function executor implementation
*
* @author etirelli
*/
public class MVELAccumulatorFunctionExecutor
implements
MVELCompileable,
Externalizable,
Accumulator {
private static final long serialVersionUID = 510l;
private final Object dummy = new Object();
private MVELCompilationUnit unit;
private org.drools.runtime.rule.AccumulateFunction function;
private DroolsMVELFactory model;
private Serializable expression;
public MVELAccumulatorFunctionExecutor() {
}
public MVELAccumulatorFunctionExecutor(MVELCompilationUnit unit,
final org.drools.runtime.rule.AccumulateFunction function) {
super();
this.unit = unit;
this.function = function;
}
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
unit = (MVELCompilationUnit) in.readObject();
function = (org.drools.runtime.rule.AccumulateFunction) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject( unit );
out.writeObject( function );
}
public void compile(ClassLoader classLoader) {
expression = unit.getCompiledExpression( classLoader );
model = unit.getFactory();
}
/* (non-Javadoc)
* @see org.drools.spi.Accumulator#createContext()
*/
public Serializable createContext() {
MVELAccumulatorFunctionContext context = new MVELAccumulatorFunctionContext();
context.context = this.function.createContext();
if ( this.function.supportsReverse() ) {
context.reverseSupport = new HashMap<Integer, Object>();
}
return context;
}
/* (non-Javadoc)
* @see org.drools.spi.Accumulator#init(java.lang.Object, org.drools.spi.Tuple, org.drools.rule.Declaration[], org.drools.WorkingMemory)
*/
public void init(Object workingMemoryContext,
Object context,
Tuple leftTuple,
Declaration[] declarations,
WorkingMemory workingMemory) throws Exception {
this.function.init( ((MVELAccumulatorFunctionContext) context).context );
}
/* (non-Javadoc)
* @see org.drools.spi.Accumulator#accumulate(java.lang.Object, org.drools.spi.Tuple, org.drools.common.InternalFactHandle, org.drools.rule.Declaration[], org.drools.rule.Declaration[], org.drools.WorkingMemory)
*/
public void accumulate(Object workingMemoryContext,
Object context,
Tuple leftTuple,
InternalFactHandle handle,
Declaration[] declarations,
Declaration[] innerDeclarations,
WorkingMemory workingMemory) throws Exception {
DroolsMVELFactory factory = (DroolsMVELFactory) workingMemoryContext;
factory.setContext( leftTuple,
null,
handle.getObject(),
workingMemory,
null );
final Object value = MVEL.executeExpression( this.expression,
this.dummy,
factory );
if ( this.function.supportsReverse() ) {
((MVELAccumulatorFunctionContext) context).reverseSupport.put( Integer.valueOf( handle.getId() ),
value );
}
this.function.accumulate( ((MVELAccumulatorFunctionContext) context).context,
value );
}
public void reverse(Object workingMemoryContext,
Object context,
Tuple leftTuple,
InternalFactHandle handle,
Declaration[] declarations,
Declaration[] innerDeclarations,
WorkingMemory workingMemory) throws Exception {
final Object value = ((MVELAccumulatorFunctionContext) context).reverseSupport.remove( Integer.valueOf( handle.getId() ) );
this.function.reverse( ((MVELAccumulatorFunctionContext) context).context,
value );
}
/* (non-Javadoc)
* @see org.drools.spi.Accumulator#getResult(java.lang.Object, org.drools.spi.Tuple, org.drools.rule.Declaration[], org.drools.WorkingMemory)
*/
public Object getResult(Object workingMemoryContext,
Object context,
Tuple leftTuple,
Declaration[] declarations,
WorkingMemory workingMemory) throws Exception {
return this.function.getResult( ((MVELAccumulatorFunctionContext) context).context );
}
public boolean supportsReverse() {
return this.function.supportsReverse();
}
public Object createWorkingMemoryContext() {
return this.model.clone();
}
private static class MVELAccumulatorFunctionContext
implements
Externalizable {
public Serializable context;
public Map<Integer, Object> reverseSupport;
public MVELAccumulatorFunctionContext() {
}
@SuppressWarnings("unchecked")
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
context = (Serializable) in.readObject();
reverseSupport = (Map<Integer, Object>) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject( context );
out.writeObject( reverseSupport );
}
}
}