com.saxonica.stream.feed
Class EventFeed

java.lang.Object
  com.saxonica.stream.feed.EventFeed

All Implemented Interfaces:

Feed

Direct Known Subclasses:

ComplexNodeEventFeed, ForkingFeed

public abstract class EventFeed
extends Object
implements Feed

An EventFeed evaluates an expression in "decomposed push" mode. Its streaming input is supplied via a sequence of calls that notify individual events in the input sequence, and its output is (in most cases) delivered via a sequence of calls to the receiver representing the parent expression. The exception is the FeedToReceiver class which appends the supplied items to a Receiver.

Constructor Summary

EventFeed(Expression exp, Feed result, Stack<XPathContext> contextStack)

Method Summary

void	append(Item item) Append an item (node or atomic value) to the output
void	close() Finish evaluating the expression.
XPathContext	getContext() Get the dynamic evaluation context
Stack<XPathContext>	getContextStack() Get the stack of XPathContext objects
Expression	getExpression() Get the expression being evaluated by this EventFeed
PipelineConfiguration	getPipelineConfiguration() Get the pipeline configuration
Feed	getResult() Get the parent expression feed
void	open() Start evaluating the expression.
void	setPipelineConfiguration(PipelineConfiguration pipe) Set the pipeline configuration

Methods inherited from class java.lang.Object

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

Constructor Detail

EventFeed

public EventFeed(Expression exp,
                 Feed result,
                 Stack<XPathContext> contextStack)

Method Detail

setPipelineConfiguration

public void setPipelineConfiguration(PipelineConfiguration pipe)

Set the pipeline configuration

Parameters:

pipe - the pipeline configuration

getPipelineConfiguration

public PipelineConfiguration getPipelineConfiguration()

Get the pipeline configuration

Specified by:

getPipelineConfiguration in interface Feed

Returns:

the pipeline configuration

getResult

public Feed getResult()

Get the parent expression feed

getExpression

public Expression getExpression()

Get the expression being evaluated by this EventFeed

Returns:

the expression being evaluated

getContext

public XPathContext getContext()

Get the dynamic evaluation context

Returns:

the dynamic evaluation context

getContextStack

public Stack<XPathContext> getContextStack()

Get the stack of XPathContext objects

Returns:

the context stack

open

public void open()
          throws XPathException

Start evaluating the expression. This must call open() on the parent expression feed before it does anything else. For the default implementation, this is all that it does. Note that it does not open the destination receiver.

Specified by:

open in interface Feed

Throws:

XPathException - if a dynamic error occurs

append

public void append(Item item)
            throws XPathException

Append an item (node or atomic value) to the output

Specified by:

append in interface Feed

Parameters:

item - the item to be appended

Throws:

XPathException - to report any failure

close

public void close()
           throws XPathException

Finish evaluating the expression. This must call close() on the parent expression feed as the last thing it does. For the default implementation, this is all that it does. Note that it does not close the destination receiver.

Specified by:

close in interface Feed

Throws:

XPathException - if a dynamic error occurs