/**
* 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.Collection;
import org.drools.WorkingMemory;
import org.drools.common.InternalFactHandle;
import org.drools.common.InternalWorkingMemory;
import org.drools.rule.Collect;
import org.drools.rule.Declaration;
import org.drools.spi.Accumulator;
import org.drools.spi.Tuple;
/**
* An accumulator to execute "collect" CEs
*
* @author etirelli
*/
public class CollectAccumulator
implements
Accumulator,
Externalizable {
private static final long serialVersionUID = 510l;
private Collect collect;
public CollectAccumulator() {
}
public CollectAccumulator( final Collect collect ) {
this.collect = collect;
}
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
this.collect = (Collect) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject( this.collect );
}
/* (non-Javadoc)
* @see org.drools.spi.Accumulator#createContext()
*/
public Serializable createContext() {
return new CollectContext();
}
/* (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 {
((CollectContext) context).result = this.collect.instantiateResultObject( (InternalWorkingMemory) workingMemory );
}
/* (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 {
((CollectContext) context).result.add( handle.getObject() );
}
public void reverse(Object workingMemoryContext,
Object context,
Tuple leftTuple,
InternalFactHandle handle,
Declaration[] declarations,
Declaration[] innerDeclarations,
WorkingMemory workingMemory) throws Exception {
((CollectContext) context).result.remove( handle.getObject() );
}
/* (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 ((CollectContext) context).result;
}
public boolean supportsReverse() {
return true;
}
public Object createWorkingMemoryContext() {
// no working memory context needed
return null;
}
private static class CollectContext
implements
Externalizable {
public Collection<Object> result;
public CollectContext() {}
@SuppressWarnings("unchecked")
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
result = (Collection<Object>) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject( result );
}
}
}