Package net.sf.saxon.expr.accum

Class AccumulatorManager

java.lang.Object

net.sf.saxon.expr.accum.AccumulatorManager

public class AccumulatorManager
extends java.lang.Object

Manager for accumulator functions (XSLT 3.0).

In principle there is a dataset containing accumulator values for every accumulator/document pair. In addition, if the same stylesheet is run concurrently in multiple transformations, and a document is shared between these transformations, the data values for the accumulator can differ between the two transformations, because the accumulator rules can depend on values of stylesheet parameters or on context variables such as current-dateTime.

It is important that the accumulator data for a tree does not cause the tree to be locked in memory for the duration of a transformation. We therefore keep a weak reference to the tree. For each tree, until it is garbage collected, there is a map from accumulator names to accumulator data.

Constructor Summary

Constructors

Constructor	Description
AccumulatorManager()

Method Summary

Modifier and Type	Method	Description
void	addAccumulatorData(TreeInfo doc, Accumulator acc, IAccumulatorData accData)	Add the accumulator data for a particular accumulator, if it does not already exist
IAccumulatorData	getAccumulatorData(TreeInfo doc, Accumulator acc, XPathContext context)	Get the data relating to a particular accumulator for a particular unstreamed document tree
boolean	isApplicable(TreeInfo tree, Accumulator accumulator)	Ask whether a particular accumulator is applicable to a particular tree
void	setApplicableAccumulators(TreeInfo tree, java.util.Set<? extends Accumulator> accumulators)	By default, all accumulators are applicable to any given tree.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AccumulatorManager

public AccumulatorManager()

Method Detail

setApplicableAccumulators

public void setApplicableAccumulators(TreeInfo tree,
                                      java.util.Set<? extends Accumulator> accumulators)

By default, all accumulators are applicable to any given tree. If this method is called, a specific set of accumulators are registered as applicable. This set may be empty.

Parameters:

tree - the document tree in question

accumulators - the set of accumulators that are appicable

isApplicable

public boolean isApplicable(TreeInfo tree,
                            Accumulator accumulator)

Ask whether a particular accumulator is applicable to a particular tree

Parameters:

tree - the tree in question

accumulator - the accumulator in question

Returns:

true if the accumulator is applicable to this tree, otherwise false

getAccumulatorData

public IAccumulatorData getAccumulatorData(TreeInfo doc,
                                           Accumulator acc,
                                           XPathContext context)
                                    throws XPathException

Get the data relating to a particular accumulator for a particular unstreamed document tree

Parameters:

doc - the source document tree in question

acc - the required accumulator

context - the XPath dynamic evaluation context

Returns:

a data structure holding the evaluated values of the accumulator for this source document

Throws:

XPathException - if any dynamic error occurs

addAccumulatorData

public void addAccumulatorData(TreeInfo doc,
                               Accumulator acc,
                               IAccumulatorData accData)

Add the accumulator data for a particular accumulator, if it does not already exist

Parameters:

doc - the document/tree whose accumulator data is being added

acc - the accumulator in question

accData - the data holding the values of the accumulator for the nodes in this tree