com.saxonica.ee.stream.feed

Class CopyOfFeed

java.lang.Object

com.saxonica.ee.stream.feed.ItemFeed

com.saxonica.ee.stream.feed.AbsorptionFeed

com.saxonica.ee.stream.feed.CopyOfFeed

All Implemented Interfaces:

Feed

public class CopyOfFeed
extends AbsorptionFeed

This class is used when optimizing a streaming copy, that is, when evaluating a construct of the form saxon:stream(doc('a.xml')/a/b/c). When the matched element (c in this example) is encountered, this Watch detects the fact, and activates a Receiver to receive subsequent events and construct a tree being a copy of the subtree rooted at c. On completion, this tree is written to the supplied SequenceWriter. This will often be a Conduit, where hopefully an iterator is waiting for it on another thread.

Nested Class Summary

Nested classes/interfaces inherited from class com.saxonica.ee.stream.feed.AbsorptionFeed

AbsorptionFeed.PendingItem

Constructor Summary

Constructors

Constructor and Description
CopyOfFeed(Feed result, XPathContext context)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Finish evaluating the expression.
void	dynamicError(XPathException error) Report a dynamic error.
SequenceReceiver	getReceiver() Get a receiver to which start and end events for documents and elements can be written.
static Trigger	getWatch(Feed result, Pattern selection, WatchManager wm, XPathContext context) Create a Watch whose effect is to create copies of the selected (streamed) nodes and pass them to the supplied feed
protected AbsorptionFeed.PendingItem	makePendingItem(int sequenceNr, FleetingParentNode node) Create a pending item (appropriate to the subclass) containing the data needed to compute the result value for one node in the streamed input sequence
protected Sequence	processGroundedItem(Item item) Process a grounded item in the input sequence: either a streamed leaf node such as an attribute or text node, or an atomic value, or a non-streamed element or document node injected into the sequence for example by use of the comma operator.
void	setCopyNamespaces(boolean copy) Say whether unused namespaces are to be copied
void	setValidationOptions(int validation, SchemaType type) Set the options for schema validation

Methods inherited from class com.saxonica.ee.stream.feed.AbsorptionFeed

endSelectedParentNode, processItem, setHasFailed, startSelectedParentNode

Methods inherited from class com.saxonica.ee.stream.feed.ItemFeed

getContext, getExpression, getPipelineConfiguration, getResult, getTerminator, hasFailed, open, processItems, setExpression, setPipelineConfiguration, setTerminator

Methods inherited from class java.lang.Object

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

Constructor Detail

CopyOfFeed

public CopyOfFeed(Feed result,
          XPathContext context)

Method Detail

getWatch

public static Trigger getWatch(Feed result,
               Pattern selection,
               WatchManager wm,
               XPathContext context)

Create a Watch whose effect is to create copies of the selected (streamed) nodes and pass them to the supplied feed

Parameters:

result - The feed to which the copied nodes should be supplied

selection - defines the nodes to be selected

wm - The WatchManager that will notify the selected nodes

context - the XPath evaluation context

Returns:

the new Watch

close

public void close()
           throws XPathException

Description copied from class: ItemFeed

Finish evaluating the expression. The default implementation does nothing.

Specified by:

close in interface Feed

Overrides:

close in class ItemFeed

Throws:

XPathException - if a dynamic error occurs

setCopyNamespaces

public void setCopyNamespaces(boolean copy)

Say whether unused namespaces are to be copied

Parameters:

copy - true if unused namespace declarations should be copied to the result tree (this is the default

setValidationOptions

public void setValidationOptions(int validation,
                        SchemaType type)

Set the options for schema validation

Parameters:

validation - the validation mode, e.g. strict, lax, preserve, strip

type - the type to validate against

getReceiver

public SequenceReceiver getReceiver()

Get a receiver to which start and end events for documents and elements can be written. By default this will be the same as the receiver for the result feed, because very few XSLT constructs (specifically, variables and functions) allow the results of document and element constructors to be captured for further processing. A construct that does need to process these events will intercept them by providing its own receiver, typically a SequenceOutputter.

Specified by:

getReceiver in interface Feed

Overrides:

getReceiver in class ItemFeed

Returns:

the receiver

makePendingItem

protected AbsorptionFeed.PendingItem makePendingItem(int sequenceNr,
                                         FleetingParentNode node)

Description copied from class: AbsorptionFeed

Create a pending item (appropriate to the subclass) containing the data needed to compute the result value for one node in the streamed input sequence

Specified by:

makePendingItem in class AbsorptionFeed

Parameters:

sequenceNr - the sequence number of this node within a set of nested nodes

node - the streamed input node

Returns:

the data needed to process this node

processGroundedItem

protected Sequence processGroundedItem(Item item)
                                throws XPathException

Description copied from class: AbsorptionFeed

Process a grounded item in the input sequence: either a streamed leaf node such as an attribute or text node, or an atomic value, or a non-streamed element or document node injected into the sequence for example by use of the comma operator.

Specified by:

processGroundedItem in class AbsorptionFeed

Parameters:

item - the grounded item

Returns:

the result of processing the grounded item

Throws:

XPathException - if a dynamic error occurs

dynamicError

public void dynamicError(XPathException error)
                  throws XPathException

Report a dynamic error. This requires searching up the "feed" pipeline to see if there is a try/catch expression interested in being notified of this error; if there is none, the error is thrown as an exception

Overrides:

dynamicError in class ItemFeed

Parameters:

error - the exception representing the dynamic error

Throws:

XPathException - if there is no try/catch expression wanting to catch this error