net.sf.saxon.option.axiom.AxiomObjectModel Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of Saxon-HE Show documentation
Show all versions of Saxon-HE Show documentation
The XSLT and XQuery Processor
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2018-2022 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.option.axiom;
import net.sf.saxon.Configuration;
import net.sf.saxon.event.Builder;
import net.sf.saxon.event.PipelineConfiguration;
import net.sf.saxon.event.Receiver;
import net.sf.saxon.expr.JPConverter;
import net.sf.saxon.expr.PJConverter;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.lib.ExternalObjectModel;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.om.GroundedValue;
import net.sf.saxon.om.NodeInfo;
import net.sf.saxon.om.Sequence;
import net.sf.saxon.om.TreeModel;
import net.sf.saxon.pattern.AnyNodeTest;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.tree.wrapper.VirtualNode;
import net.sf.saxon.type.ItemType;
import org.apache.axiom.om.*;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
/**
* This interface must be implemented by any third-party object model that can
* be wrapped with a wrapper that implements the Saxon Object Model (the NodeInfo interface).
* This implementation of the interface supports wrapping of Axiom Documents.
*/
public class AxiomObjectModel extends TreeModel implements ExternalObjectModel {
private static final AxiomObjectModel THE_INSTANCE = new AxiomObjectModel();
public static AxiomObjectModel getInstance() {
return THE_INSTANCE;
}
public AxiomObjectModel() {
}
/**
* Get the name of a characteristic class, which, if it can be loaded, indicates that the supporting libraries
* for this object model implementation are available on the classpath
*
* @return by convention (but not necessarily) the class that implements a document node in the relevant
* external model
*/
@Override
public String getDocumentClassName() {
return "org.apache.axiom.om.OMDocument";
}
/**
* Get the URI of the external object model as used in the JAXP factory interfaces for obtaining
* an XPath implementation
*/
@Override
public String getIdentifyingURI() {
return NamespaceConstant.OBJECT_MODEL_AXIOM;
}
@Override
public Builder makeBuilder(PipelineConfiguration pipe) {
return new AxiomWriter(pipe);
}
@Override
public int getSymbolicValue() {
return Builder.AXIOM_TREE;
}
@Override
public String getName() {
return "Axiom";
}
/**
* Test whether this object model recognizes a given node as one of its own
*
* @param object the object in question
* @return true if the object is a JDOM node
*/
private static boolean isRecognizedNode(Object object) {
return object instanceof OMDocument ||
object instanceof OMElement ||
object instanceof OMAttribute ||
object instanceof OMText ||
object instanceof OMComment ||
object instanceof OMProcessingInstruction ||
object instanceof OMNamespace;
}
/*@Nullable*/
@Override
public PJConverter getPJConverter(Class targetClass) {
if (isRecognizedNodeClass(targetClass)) {
return new PJConverter() {
@Override
public Object convert(Sequence value, Class targetClass, XPathContext context) {
return convertXPathValueToObject(value, targetClass);
}
};
} else {
return null;
}
}
@Override
public JPConverter getJPConverter(Class sourceClass, Configuration config) {
if (isRecognizedNodeClass(sourceClass)) {
return new JPConverter() {
@Override
public GroundedValue convert(Object object, XPathContext context) throws XPathException {
return convertObjectToXPathValue(object, context.getConfiguration());
}
@Override
public ItemType getItemType() {
return AnyNodeTest.getInstance();
}
};
} else {
return null;
}
}
/**
* Get a converter that converts a sequence of XPath nodes to this model's representation
* of a node list.
*
* @param node an example of the kind of node used in this model
* @return if the model does not recognize this node as one of its own, return null. Otherwise
* return a PJConverter that takes a list of XPath nodes (represented as NodeInfo objects) and
* returns a collection of nodes in this object model
*/
@Override
public PJConverter getNodeListCreator(Object node) {
return null;
}
/**
* Test whether this object model recognizes a given class as representing a
* node in that object model. This method will generally be called at compile time.
*
* @param nodeClass A class that possibly represents nodes
* @return true if the class is used to represent nodes in this object model
*/
private boolean isRecognizedNodeClass(Class nodeClass) {
return OMDocument.class.isAssignableFrom(nodeClass) ||
OMElement.class.isAssignableFrom(nodeClass) ||
OMAttribute.class.isAssignableFrom(nodeClass) ||
OMText.class.isAssignableFrom(nodeClass) ||
OMComment.class.isAssignableFrom(nodeClass) ||
OMProcessingInstruction.class.isAssignableFrom(nodeClass) ||
OMNamespace.class.isAssignableFrom(nodeClass);
}
/**
* Test whether this object model recognizes a particular kind of JAXP Result object,
* and if it does, return a Receiver that builds an instance of this data model from
* a sequence of events. If the Result is not recognized, return null.
* @return Always null, because no Axiom Result implementation is recognized.
*/
@Override
public Receiver getDocumentBuilder(Result result) {
return null;
}
/**
* Wrap or unwrap a node using this object model to return the corresponding Saxon node. If the supplied
* source does not belong to this object model, return null
*/
@Override
public NodeInfo unravel(Source source, Configuration config) {
return null;
}
/**
* Convert a Java object to an XPath value. If the supplied object is recognized as a representation
* of a value using this object model, the object model should convert the value to an XPath value
* and return this as the result. If not, it should return null. If the object is recognized but cannot
* be converted, an exception should be thrown
*
* @param object the object to be converted . If this is not a JDOM node, the method returns null
* @param config the Saxon Configuration
* @return either an XPath node that wraps the supplied JDOM node, or null
*/
/*@Nullable*/
private GroundedValue convertObjectToXPathValue(Object object, Configuration config) {
if (isRecognizedNode(object)) {
if (object instanceof OMDocument) {
return new AxiomDocument((OMDocument) object, "", config).getRootNode();
} else if (object instanceof OMNode) {
AxiomDocument docWrapper = new AxiomDocument(getOMDocument((OMNode) object), "", config);
return wrapNode(docWrapper, object);
} else if (object instanceof OMAttribute) {
AxiomDocument docWrapper = new AxiomDocument(
getOMDocument(((OMAttribute) object).getOwner()), "", config);
return wrapNode(docWrapper, object);
} else {
return null;
}
} else {
return null;
}
}
private static OMDocument getOMDocument(OMNode node) {
OMContainer parent;
if (node instanceof OMContainer) {
parent = (OMContainer) node;
} else {
parent = node.getParent();
}
while (!(parent instanceof OMDocument) && parent != null) {
parent = node.getParent();
}
return (OMDocument) parent;
}
/**
* Convert an XPath value to an object in this object model. If the supplied value can be converted
* to an object in this model, of the specified class, then the conversion should be done and the
* resulting object returned. If the value cannot be converted, the method should return null. Note
* that the supplied class might be a List, in which case the method should inspect the contents of the
* Value to see whether they belong to this object model.
*
* @param value the XPath value to be converted
* @param target the Java class required for the result of the conversion
* @return the object that results from conversion if conversion is possible, or null otherwise
*/
/*@Nullable*/
private Object convertXPathValueToObject(Sequence value, Class target) {
if (value instanceof VirtualNode) {
Object u = ((VirtualNode) value).getRealNode();
if (target.isAssignableFrom(u.getClass())) {
return u;
}
}
return null;
}
/**
* Wrap a node within the external object model in a node wrapper that implements the Saxon
* VirtualNode interface (which is an extension of NodeInfo)
*
* @param document the document wrapper, as a DocumentInfo object
* @param node the node to be wrapped. This must be a node within the document wrapped by the
* DocumentInfo provided in the first argument
* @return the wrapper for the node, as an instance of VirtualNode
*/
public NodeInfo wrapNode(AxiomDocument document, Object node) {
if (node instanceof OMDocument) {
return document.getRootNode();
} else if (node instanceof OMNode) {
return AxiomDocument.makeWrapper((OMNode) node, document, null, -1);
} else if (node instanceof OMAttribute) {
AxiomElementNodeWrapper elem = (AxiomElementNodeWrapper) wrapNode(document, ((OMAttribute) node).getOwner());
return new AxiomAttributeWrapper((OMAttribute) node, elem, -1);
} else {
throw new IllegalArgumentException();
}
}
}