org.drools.spi
Interface Accumulator

All Superinterfaces:

Invoker, RuleComponent

All Known Implementing Classes:

CollectAccumulator, JavaAccumulatorFunctionExecutor, MVELAccumulator, MVELAccumulatorFunctionExecutor

public interface Accumulator
extends Invoker

Accumulator Created: 04/06/2006

Version:

$Id$

Method Summary

void	accumulate(Object workingMemoryContext, Object context, Tuple leftTuple, InternalFactHandle handle, Declaration[] declarations, Declaration[] innerDeclarations, WorkingMemory workingMemory) Executes the accumulate (action) code for the given fact handle
Serializable	createContext() Creates the context object for an accumulator session.
Object	createWorkingMemoryContext() Creates and return a context object for each working memory instance
Object	getResult(Object workingMemoryContext, Object context, Tuple leftTuple, Declaration[] declarations, WorkingMemory workingMemory) Gets the result of the accummulation
void	init(Object workingMemoryContext, Object context, Tuple leftTuple, Declaration[] declarations, WorkingMemory workingMemory) Executes the initialization block of code
void	reverse(Object workingMemoryContext, Object context, Tuple leftTuple, InternalFactHandle handle, Declaration[] declarations, Declaration[] innerDeclarations, WorkingMemory workingMemory) Reverses the accumulate action for the given fact handle
boolean	supportsReverse() Returns true if this accumulator supports operation reversal

Method Detail

createWorkingMemoryContext

Object createWorkingMemoryContext()

Creates and return a context object for each working memory instance

Returns:

createContext

Serializable createContext()

Creates the context object for an accumulator session. The context is passed as a parameter to every subsequent accumulator method call in the same session.

Returns:

init

void init(Object workingMemoryContext,
          Object context,
          Tuple leftTuple,
          Declaration[] declarations,
          WorkingMemory workingMemory)
          throws Exception

Executes the initialization block of code

Parameters:

leftTuple - tuple causing the rule fire

declarations - previous declarations

workingMemory -

Throws:

Exception

accumulate

void accumulate(Object workingMemoryContext,
                Object context,
                Tuple leftTuple,
                InternalFactHandle handle,
                Declaration[] declarations,
                Declaration[] innerDeclarations,
                WorkingMemory workingMemory)
                throws Exception

Executes the accumulate (action) code for the given fact handle

Parameters:

leftTuple -

handle -

declarations -

innerDeclarations -

workingMemory -

Throws:

Exception

supportsReverse

boolean supportsReverse()

Returns true if this accumulator supports operation reversal

Returns:

reverse

void reverse(Object workingMemoryContext,
             Object context,
             Tuple leftTuple,
             InternalFactHandle handle,
             Declaration[] declarations,
             Declaration[] innerDeclarations,
             WorkingMemory workingMemory)
             throws Exception

Reverses the accumulate action for the given fact handle

Parameters:

context -

leftTuple -

handle -

declarations -

innerDeclarations -

workingMemory -

Throws:

Exception

getResult

Object getResult(Object workingMemoryContext,
                 Object context,
                 Tuple leftTuple,
                 Declaration[] declarations,
                 WorkingMemory workingMemory)
                 throws Exception

Gets the result of the accummulation

Parameters:

leftTuple -

declarations -

workingMemory -

Returns:

Throws:

Exception