org.apache.ws.commons.schema.docpath.SaxWalkerOverDom Maven / Gradle / Ivy
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Code to walk an XML Schema and confirm an XML Document conforms to it.
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.ws.commons.schema.docpath;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.xml.namespace.QName;
import org.apache.ws.commons.schema.constants.Constants;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
/**
* Walks over a {@link Document} in a SAX style, notifying listeners with SAX
* events.
*
* Because the document has already been processed, only the following methods
* in the {@link ContentHandler} will be called:
*
* - {@link ContentHandler#startDocument()}
* - {@link ContentHandler#startPrefixMapping(String, String)}
* - {@link ContentHandler#startElement(String, String, String, Attributes)}
* - {@link ContentHandler#characters(char[], int, int)}
* - {@link ContentHandler#endElement(String, String, String)}
* - {@link ContentHandler#endPrefixMapping(String)}
* - {@link ContentHandler#endDocument()}
*
*
*/
public final class SaxWalkerOverDom {
private List listeners;
private static class Attr {
final QName qName;
final String qualifiedName;
final String value;
Attr(String namespace, String localName, String qualName, String val) {
qName = new QName(namespace, localName);
qualifiedName = qualName;
value = val;
}
Attr(Node node) {
this(node.getNamespaceURI(), node.getLocalName(), node.getNodeName(), node.getNodeValue());
}
}
private static class DomAttrsAsSax implements org.xml.sax.Attributes {
private final List attributes;
private final Map attrsByQualifiedName;
private final Map attrsByQName;
private final Map indexByQualifiedName;
private final Map indexByQName;
DomAttrsAsSax(NamedNodeMap domAttrs) throws SAXException {
attributes = new ArrayList();
attrsByQualifiedName = new HashMap();
attrsByQName = new HashMap();
indexByQualifiedName = new HashMap();
indexByQName = new HashMap();
if (domAttrs != null) {
for (int attrIdx = 0; attrIdx < domAttrs.getLength(); ++attrIdx) {
final Node domAttr = domAttrs.item(attrIdx);
if (Constants.XMLNS_ATTRIBUTE_NS_URI.equals(domAttr.getNamespaceURI())) {
// Namespace declarations will be handled separately.
continue;
}
final Attr attribute = new Attr(domAttr);
attributes.add(attribute);
attrsByQualifiedName.put(attribute.qualifiedName, attribute);
attrsByQName.put(attribute.qName, attribute);
indexByQualifiedName.put(attribute.qualifiedName, attrIdx);
indexByQName.put(attribute.qName, attrIdx);
}
}
}
@Override
public int getLength() {
return attributes.size();
}
@Override
public String getURI(int index) {
if (attributes.size() <= index) {
return null;
} else {
return attributes.get(index).qName.getNamespaceURI();
}
}
@Override
public String getLocalName(int index) {
if (attributes.size() <= index) {
return null;
} else {
return attributes.get(index).qName.getLocalPart();
}
}
@Override
public String getQName(int index) {
if (attributes.size() <= index) {
return null;
} else {
return attributes.get(index).qualifiedName;
}
}
@Override
public String getType(int index) {
if (attributes.size() <= index) {
return null;
} else {
return "CDATA"; // We do not know the type information.
}
}
@Override
public String getValue(int index) {
if (attributes.size() <= index) {
return null;
} else {
return attributes.get(index).value;
}
}
@Override
public int getIndex(String uri, String localName) {
if ((uri == null) || (localName == null)) {
return -1;
}
final QName qName = new QName(uri, localName);
final Integer index = indexByQName.get(qName);
if (index == null) {
return -1;
} else {
return index;
}
}
@Override
public int getIndex(String qName) {
if (qName == null) {
return -1;
}
final Integer index = indexByQualifiedName.get(qName);
if (index == null) {
return -1;
} else {
return index;
}
}
@Override
public String getType(String uri, String localName) {
if ((uri == null) || (localName == null)) {
return null;
} else {
final Attr attr = attrsByQName.get(new QName(uri, localName));
return (attr == null) ? null : "CDATA";
}
}
@Override
public String getType(String qName) {
if (qName == null) {
return null;
} else {
final Attr attr = attrsByQualifiedName.get(qName);
return (attr == null) ? null : "CDATA";
}
}
@Override
public String getValue(String uri, String localName) {
if ((uri == null) || (localName == null)) {
return null;
} else {
final Attr attr = attrsByQName.get(new QName(uri, localName));
return (attr == null) ? null : attr.value;
}
}
@Override
public String getValue(String qName) {
if (qName == null) {
return null;
} else {
final Attr attr = attrsByQualifiedName.get(qName);
return (attr == null) ? null : attr.value;
}
}
}
/**
* Constructs a new SaxWalkerOverDom.
*/
public SaxWalkerOverDom() {
listeners = null;
}
/**
* Constructs a new SaxWalkerOverDom with the provided
* {@link ContentHandler} to send SAX events.
*
* @param contentHandler The content handler to send events to.
*/
public SaxWalkerOverDom(ContentHandler contentHandler) {
this();
listeners = new ArrayList(1);
listeners.add(contentHandler);
}
/**
* Constructs a new SaxWalkerOverDom, taking ownership of the
* list of {@link ContentHandler}s to send events to.
*
* @param contentHandlers The list of content handlers to send events to.
*/
public SaxWalkerOverDom(List contentHandlers) {
this();
listeners = contentHandlers;
}
/**
* Adds the provided {@link ContentHandler} to the list of content handlers
* to send events to. If this content handler was already added, it will be
* sent events twice (or more often).
*
* @param contentHandler The content handler to send events to.
*/
public void addContentHandler(ContentHandler contentHandler) {
if (listeners == null) {
listeners = new ArrayList(1);
}
listeners.add(contentHandler);
}
/**
* Removes the first instance of the provided {@link ContentHandler} from
* the set of handlers to send events to. If the content handler was added
* more than once, it will continue to receive events.
*
* @param contentHandler The content handler to stop sending events to.
* @return true if it was found, false if not.
*/
public boolean removeContentHandler(ContentHandler contentHandler) {
if (listeners != null) {
return listeners.remove(contentHandler);
}
return false;
}
/**
* Walks the provided {@link Document}, sending events to all of the
* {@link ContentHandler}s as it traverses. If there are no content
* handlers, this method is a no-op.
*
* @param document The {@link Document} to traverse.
* @param systemId The system ID of this {@link Document}.
* @throws SAXException if an exception occurs when notifying the handlers.
*/
public void walk(Document document) throws SAXException {
if (document == null) {
throw new IllegalArgumentException("Document cannot be null.");
}
if ((listeners == null) || listeners.isEmpty()) {
return;
}
for (ContentHandler listener : listeners) {
listener.startDocument();
}
final List prefixes = startPrefixMappings(document);
walk(document.getDocumentElement());
for (ContentHandler listener : listeners) {
for (String prefix : prefixes) {
listener.endPrefixMapping(prefix);
}
listener.endDocument();
}
}
private void walk(Element element) throws SAXException {
DomAttrsAsSax attrs = new DomAttrsAsSax(element.getAttributes());
final List prefixes = startPrefixMappings(element);
for (ContentHandler listener : listeners) {
listener.startElement(convertNullToEmptyString(element.getNamespaceURI()),
convertNullToEmptyString(element.getLocalName()),
convertNullToEmptyString(element.getNodeName()), attrs);
}
NodeList children = element.getChildNodes();
for (int childIndex = 0; childIndex < children.getLength(); ++childIndex) {
Node node = children.item(childIndex);
if (node instanceof Element) {
walk((Element)node);
} else if (node instanceof Text) {
walk((Text)node);
} else if (node instanceof org.w3c.dom.Comment) {
// Ignored.
} else {
throw new SAXException("Unrecognized child of " + element.getTagName() + " of type "
+ node.getClass().getName());
}
}
for (ContentHandler listener : listeners) {
listener.endElement(convertNullToEmptyString(element.getNamespaceURI()),
convertNullToEmptyString(element.getLocalName()),
convertNullToEmptyString(element.getNodeName()));
for (String prefix : prefixes) {
listener.endPrefixMapping(prefix);
}
}
}
private void walk(Text text) throws SAXException {
/*
* TODO: getData() may throw a org.w3c.dom.DOMException if the actual
* text data is too large to fit into a single DOMString (the DOM impl's
* internal storage of text data). If that's the case, substringData()
* must be called to retrieve the data in pieces. The documentation does
* not supply information on the maximum DOMString size; it appears to
* require trial & error.
*/
if (text.getLength() > 0) {
char[] data = text.getData().toCharArray();
for (ContentHandler listener : listeners) {
listener.characters(data, 0, data.length);
}
}
}
private static String convertNullToEmptyString(String input) {
if (input == null) {
return "";
}
return input;
}
private List startPrefixMappings(Node node) throws DOMException, SAXException {
switch (node.getNodeType()) {
case Node.DOCUMENT_NODE:
case Node.ELEMENT_NODE:
break;
default:
throw new IllegalArgumentException("Cannot start prefix mappings for a node of type "
+ node.getNodeType());
}
final ArrayList prefixes = new ArrayList();
final NamedNodeMap attrs = node.getAttributes();
if (attrs == null) {
return prefixes;
}
for (int attrIndex = 0; attrIndex < attrs.getLength(); ++attrIndex) {
final Node attr = attrs.item(attrIndex);
final String attrUri = attr.getNamespaceURI();
if (Constants.XMLNS_ATTRIBUTE_NS_URI.equals(attrUri)) {
final String localName = attr.getLocalName();
String prefix = null;
if (Constants.XMLNS_ATTRIBUTE.equals(localName)) {
prefix = Constants.DEFAULT_NS_PREFIX;
} else {
prefix = localName;
}
prefixes.add(prefix);
for (ContentHandler listener : listeners) {
listener.startPrefixMapping(prefix, attr.getNodeValue());
}
}
}
return prefixes;
}
}
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