org.drools.core.spi

Interface Accumulator

All Superinterfaces:

Invoker, RuleComponent

All Known Subinterfaces:

MvelAccumulator

All Known Implementing Classes:

Accumulator.SafeAccumulator, CollectAccumulator, JavaAccumulatorFunctionExecutor

public interface Accumulator
extends Invoker

Accumulator Created: 04/06/2006

Version:

$Id$

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Accumulator.SafeAccumulator This class is used as a wrapper delegate when a security policy is in place.

Method Summary

Modifier and Type	Method and Description
Object	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
Object	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
Object	init(Object workingMemoryContext, Object context, Tuple leftTuple, Declaration[] declarations, WorkingMemory workingMemory) Executes the initialization block of code
static boolean	isCompiledInvoker(Accumulator accumulator)
boolean	supportsReverse() Returns true if this accumulator supports operation reversal
boolean	tryReverse(Object workingMemoryContext, Object context, Tuple leftTuple, InternalFactHandle handle, Object value, Declaration[] declarations, Declaration[] innerDeclarations, WorkingMemory workingMemory) Reverses the accumulate action for the given fact handle

Method Detail

createWorkingMemoryContext

Object createWorkingMemoryContext()

Creates and return a context object for each working memory instance

Returns:

createContext

Object 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

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

Executes the initialization block of code

Parameters:

leftTuple - tuple causing the rule fire

declarations - previous declarations

workingMemory -

Throws:

Exception

accumulate

Object 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

Parameters:

leftTuple -

handle -

declarations -

innerDeclarations -

workingMemory -

Throws:

Exception

supportsReverse

boolean supportsReverse()

Returns true if this accumulator supports operation reversal

Returns:

tryReverse

boolean tryReverse(Object workingMemoryContext,
                   Object context,
                   Tuple leftTuple,
                   InternalFactHandle handle,
                   Object value,
                   Declaration[] declarations,
                   Declaration[] innerDeclarations,
                   WorkingMemory workingMemory)

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)

Gets the result of the accummulation

Parameters:

leftTuple -

declarations -

workingMemory -

Returns:

Throws:

Exception

isCompiledInvoker

static boolean isCompiledInvoker(Accumulator accumulator)