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An OSGi bundle for Saxon-HE
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2013 Saxonica Limited.
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.s9api;
import net.sf.saxon.Configuration;
import net.sf.saxon.event.Builder;
import net.sf.saxon.event.PipelineConfiguration;
import net.sf.saxon.event.ProxyReceiver;
import net.sf.saxon.event.Receiver;
import net.sf.saxon.om.Item;
import net.sf.saxon.om.NodeInfo;
import net.sf.saxon.om.NodeName;
import net.sf.saxon.om.TreeModel;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.SchemaType;
import java.net.URI;
/**
* An XdmDestination is a {@link Destination} in which an {@link XdmNode}
* is constructed to hold the output of a query or transformation:
* that is, a tree using Saxon's implementation of the XDM data model
*
* No data needs to be supplied to the XdmDestination object. The query or transformation
* populates an XdmNode, which may then be retrieved using the getXdmNode
* method.
*
* An XdmDestination is designed to hold a single tree rooted at a document or element node.
* It should therefore not be used as the destination of a query that produces multiple
* documents, multiple elements, nodes other than elements and documents, or atomic values. If the query
* does produce such a result, an exception will be thrown.
*
* An XdmDestination can be reused to hold the results of a second query or transformation only
* if the {@link #reset} method is first called to reset its state.
*
* If an XDM tree is to be built from a lexical XML document, or programmatically from the application
* by writing a sequence of events, the recommended mechanism is to use a {@link DocumentBuilder} rather
* than this class.
*/
public class XdmDestination implements Destination {
TreeModel treeModel = TreeModel.TINY_TREE;
URI baseURI;
Builder builder;
public XdmDestination() {
//builder = new TinyBuilder();
}
/**
* Set the base URI for the document node that will be created when the XdmDestination is written to.
* This method must be called before writing to the destination; it has no effect on an XdmNode that
* has already been constructed.
* @param baseURI the base URI for the node that will be constructed when the XdmDestination is written to.
* This must be an absolute URI
* @throws IllegalArgumentException if the baseURI supplied is not an absolute URI
* @since 9.1
*/
public void setBaseURI(URI baseURI) {
if (!baseURI.isAbsolute()) {
throw new IllegalArgumentException("Supplied base URI must be absolute");
}
//builder.setBaseURI(baseURI.toString());
this.baseURI = baseURI;
}
/**
* Get the base URI that will be used for the document node when the XdmDestination is written to.
* @return the base URI that will be used for the node that is constructed when the XdmDestination is written to.
* @since 9.1
*/
public URI getBaseURI() {
return baseURI;
}
/**
* Set the tree model to be used for documents constructed using this XdmDestination.
* By default, the TinyTree is used.
* @param model typically one of the constants {@link net.sf.saxon.om.TreeModel#TINY_TREE},
* {@link TreeModel#TINY_TREE_CONDENSED}, or {@link TreeModel#LINKED_TREE}. However, in principle
* a user-defined tree model can be used.
* @since 9.2
*/
public void setTreeModel(TreeModel model) {
this.treeModel = model;
}
/**
* Get the tree model to be used for documents constructed using this XdmDestination.
* By default, the TinyTree is used.
* @return the tree model in use: typically one of the constants {@link net.sf.saxon.om.TreeModel#TINY_TREE},
* {@link net.sf.saxon.om.TreeModel#TINY_TREE_CONDENSED}, or {@link TreeModel#LINKED_TREE}. However, in principle
* a user-defined tree model can be used.
* @since 9.2
*/
public TreeModel getTreeModel() {
return treeModel;
}
/**
* Return a Receiver. Saxon calls this method to obtain a Receiver, to which it then sends
* a sequence of events representing the content of an XML document.
* @param config The Saxon configuration. This is supplied so that the destination can
* use information from the configuration (for example, a reference to the name pool)
* to construct or configure the returned Receiver.
* @return the Receiver to which events are to be sent.
* @throws net.sf.saxon.s9api.SaxonApiException
* if the Receiver cannot be created
*/
public Receiver getReceiver(Configuration config) throws SaxonApiException {
TreeModel model = treeModel;
if (model == null) {
model = TreeModel.getTreeModel(config.getTreeModel());
}
PipelineConfiguration pipe = config.makePipelineConfiguration();
builder = model.makeBuilder(pipe);
if (baseURI != null) {
builder.setBaseURI(baseURI.toString());
}
return new TreeProtector(builder);
}
/**
* Close the destination, allowing resources to be released. Saxon calls this method when
* it has finished writing to the destination.
*/
public void close() throws SaxonApiException {
// no action
}
/**
* Return the node at the root of the tree, after it has been constructed.
*
* This method should not be called while the tree is under construction.
* @return the root node of the tree (always a document or element node); or null if
* nothing is written to the tree (for example, the result of a query that returns the
* empty sequence)
* @throws IllegalStateException if called during the execution of the process that
* is writing the tree.
*/
public XdmNode getXdmNode() {
if (builder == null) {
throw new IllegalStateException("The document has not yet been built");
}
NodeInfo node = builder.getCurrentRoot();
return (node == null ? null : (XdmNode)XdmValue.wrap(node));
}
/**
* Allow the XdmDestination to be reused, without resetting other properties
* of the destination.
*/
public void reset() {
builder = null;
}
/**
* TreeProtector is a filter that ensures that the events reaching the Builder constitute a single
* tree rooted at an element or document node (because anything else will crash the builder)
*/
private static class TreeProtector extends ProxyReceiver {
private int level = 0;
private boolean ended = false;
public TreeProtector(Receiver next) {
super(next);
}
@Override
public void startDocument(int properties) throws XPathException {
if (ended) {
throw new XPathException("Only a single document can be written to an XdmDestination");
}
super.startDocument(properties);
level++;
}
@Override
public void endDocument() throws XPathException {
super.endDocument();
level--;
if (level == 0) {
ended = true;
}
}
@Override
public void startElement(NodeName nameCode, SchemaType typeCode, int locationId, int properties) throws XPathException {
if (ended) {
throw new XPathException("Only a single root node can be written to an XdmDestination");
}
super.startElement(nameCode, typeCode, locationId, properties);
level++;
}
@Override
public void endElement() throws XPathException {
super.endElement();
level--;
if (level == 0) {
ended = true;
}
}
@Override
public void characters(CharSequence chars, int locationId, int properties) throws XPathException {
if (level == 0) {
throw new XPathException("When writing to an XdmDestination, text nodes are only allowed within a document or element node");
}
super.characters(chars, locationId, properties);
}
@Override
public void processingInstruction(String target, CharSequence data, int locationId, int properties) throws XPathException {
if (level == 0) {
throw new XPathException("When writing to an XdmDestination, processing instructions are only allowed within a document or element node");
}
super.processingInstruction(target, data, locationId, properties);
}
@Override
public void comment(CharSequence chars, int locationId, int properties) throws XPathException {
if (level == 0) {
throw new XPathException("When writing to an XdmDestination, comment nodes are only allowed within a document or element node");
}
super.comment(chars, locationId, properties);
}
@Override
public void append(Item item, int locationId, int copyNamespaces) throws XPathException {
if (level == 0) {
throw new XPathException("When writing to an XdmDestination, atomic values are only allowed within a document or element node");
}
super.append(item, locationId, copyNamespaces);
}
}
}