org.drools.runtime.rule.WorkingMemoryEntryPoint Maven / Gradle / Ivy
/**
* 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.runtime.rule;
import java.util.Collection;
import org.drools.KnowledgeBaseConfiguration;
import org.drools.runtime.ObjectFilter;
/**
* An entry-point is an abstract channel through where facts are inserted into the engine.
* Drools 5 supports multiple entry-points into a single StatefulKnowledgeBase: the
* default, anonymous entry-point, as well as as many user declared entry points the application
* requires.
*
* To get a reference to an entry point, just request the session:
*
* StatefulKnowledgeSession session = kbase.newStatelessKnowledgeSession();
* ...
* WorkingMemoryEntryPoint entrypoint = session.getWorkingMemoryEntryPoint("my entry point");
*
* Once a reference to an entry point is acquired, the application can insert, update and retract facts
* to/from that entry-point as usual:
*
* ...
* FactHandle factHandle = entrypoint.insert( fact );
* ...
* entrypoint.update( factHandle, newFact );
* ...
* entrypoint.retract( factHandle );
* ...
*
*
*/
public interface WorkingMemoryEntryPoint {
/**
* Returns the String Id of this entry point
*
* @return
*/
public String getEntryPointId();
/**
* Inserts a new fact into this entry point
*
* @param object
* the fact to be inserted
*
* @return the fact handle created for the given fact
*/
FactHandle insert(Object object);
/**
* Retracts the fact for which the given FactHandle was assigned.
*
* @param handle the handle whose fact is to be retracted.
*/
void retract(FactHandle handle);
/**
* Updates the fact for which the given FactHandle was assigned with the new
* fact set as the second parameter in this method.
*
* @param handle the FactHandle for the fact to be updated.
*
* @param object the new value for the fact being updated.
*/
void update(FactHandle handle,
Object object);
/**
* Returns the fact handle associated with the given object. It is important to note that this
* method behaves in accordance with the configured assert behaviour for this knowledge base
* (either IDENTITY or EQUALITY).
*
* @param object
* the fact for which the fact handle will be returned.
*
* @return the fact handle for the given object, or null in case no fact handle was found for the
* given object.
*
* @see KnowledgeBaseConfiguration
*/
FactHandle getFactHandle(Object object);
/**
* Returns the object associated with the given FactHandle.
*
* @param factHandle
* @return
*/
Object getObject(FactHandle factHandle);
/**
*
* Returns all facts from the current session as a Collection.
*
*
* This class is not a general-purpose Collection
* implementation! While this class implements the Collection interface, it
* intentionally violates Collection general contract, which mandates the
* use of the equals method when comparing objects.
*
* Instead the approach used when comparing objects with the contains(Object)
* method is dependent on the WorkingMemory configuration, where it can be configured for Identity
* or for Equality.
*
* @return
*/
Collection< Object > getObjects();
/**
* Returns all facts from the current session that are accepted by the given ObjectFilter.
*
* @param filter the filter to be applied to the returned collection of facts.
*
* @return
*/
Collection< Object > getObjects(ObjectFilter filter);
/**
* Returns all FactHandles from the current session.
*
* @return
*/
Collection< T > getFactHandles();
/**
* Returns all FactHandles from the current session for which the facts are accepted by
* the given filter.
*
* @param filter the filter to be applied to the returned collection of FactHandles.
*
* @return
*/
Collection< T > getFactHandles(ObjectFilter filter);
/**
* Returns the total number of facts currently in this entry point
*
* @return
*/
public long getFactCount();
}