/*
* Copyright 2014 Attila Szegedi, Daniel Dekany, Jonathan Revusky
*
* Licensed 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 freemarker.ext.dom;
import java.io.File;
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.net.MalformedURLException;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Attr;
import org.w3c.dom.CDATASection;
import org.w3c.dom.CharacterData;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.ProcessingInstruction;
import org.w3c.dom.Text;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import freemarker.core._UnexpectedTypeErrorExplainerTemplateModel;
import freemarker.ext.util.WrapperTemplateModel;
import freemarker.log.Logger;
import freemarker.template.AdapterTemplateModel;
import freemarker.template.DefaultObjectWrapper;
import freemarker.template.SimpleScalar;
import freemarker.template.TemplateBooleanModel;
import freemarker.template.TemplateDateModel;
import freemarker.template.TemplateHashModel;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateNodeModel;
import freemarker.template.TemplateNumberModel;
import freemarker.template.TemplateSequenceModel;
/**
* A base class for wrapping a W3C DOM Node as a FreeMarker template model.
*
* <p>
* Note that {@link DefaultObjectWrapper} automatically wraps W3C DOM {@link Node}-s into this, so you may not need to
* do that with this class manually. Though, before dropping the {@link Node}-s into the data-model, you may want to
* apply {@link NodeModel#simplify(Node)} on them.
*/
abstract public class NodeModel
implements TemplateNodeModel, TemplateHashModel, TemplateSequenceModel,
AdapterTemplateModel, WrapperTemplateModel, _UnexpectedTypeErrorExplainerTemplateModel {
static private final Logger LOG = Logger.getLogger("freemarker.dom");
private static final Object STATIC_LOCK = new Object();
static private DocumentBuilderFactory docBuilderFactory;
static private final Map xpathSupportMap = Collections.synchronizedMap(new WeakHashMap());
static private XPathSupport jaxenXPathSupport;
static private ErrorHandler errorHandler;
static Class xpathSupportClass;
static {
try {
useDefaultXPathSupport();
} catch (Exception e) {
// do nothing
}
if (xpathSupportClass == null && LOG.isWarnEnabled()) {
LOG.warn("No XPath support is available.");
}
}
/**
* The W3C DOM Node being wrapped.
*/
final Node node;
private TemplateSequenceModel children;
private NodeModel parent;
/**
* Sets the DOM Parser implementation to be used when building NodeModel
* objects from XML files.
*/
static public void setDocumentBuilderFactory(DocumentBuilderFactory docBuilderFactory) {
synchronized (STATIC_LOCK) {
NodeModel.docBuilderFactory = docBuilderFactory;
}
}
/**
* @return the DOM Parser implementation that is used when
* building NodeModel objects from XML files.
*/
static public DocumentBuilderFactory getDocumentBuilderFactory() {
synchronized (STATIC_LOCK) {
if (docBuilderFactory == null) {
DocumentBuilderFactory newFactory = DocumentBuilderFactory.newInstance();
newFactory.setNamespaceAware(true);
newFactory.setIgnoringElementContentWhitespace(true);
docBuilderFactory = newFactory; // We only write it out when the initialization was full
}
return docBuilderFactory;
}
}
/**
* sets the error handler to use when parsing the document.
*/
static public void setErrorHandler(ErrorHandler errorHandler) {
synchronized (STATIC_LOCK) {
NodeModel.errorHandler = errorHandler;
}
}
/**
* @since 2.3.20
*/
static public ErrorHandler getErrorHandler() {
synchronized (STATIC_LOCK) {
return NodeModel.errorHandler;
}
}
/**
* Create a NodeModel from a SAX input source. Adjacent text nodes will be merged (and CDATA sections
* are considered as text nodes).
* @param removeComments whether to remove all comment nodes
* (recursively) from the tree before processing
* @param removePIs whether to remove all processing instruction nodes
* (recursively from the tree before processing
*/
static public NodeModel parse(InputSource is, boolean removeComments, boolean removePIs)
throws SAXException, IOException, ParserConfigurationException {
DocumentBuilder builder = getDocumentBuilderFactory().newDocumentBuilder();
ErrorHandler errorHandler = getErrorHandler();
if (errorHandler != null) builder.setErrorHandler(errorHandler);
final Document doc;
try {
doc = builder.parse(is);
} catch (MalformedURLException e) {
// This typical error has an error message that is hard to understand, so let's translate it:
if (is.getSystemId() == null && is.getCharacterStream() == null && is.getByteStream() == null) {
throw new MalformedURLException(
"The SAX InputSource has systemId == null && characterStream == null && byteStream == null. "
+ "This is often because it was created with a null InputStream or Reader, which is often because "
+ "the XML file it should point to was not found. "
+ "(The original exception was: " + e + ")");
} else {
throw e;
}
}
if (removeComments && removePIs) {
simplify(doc);
} else {
if (removeComments) {
removeComments(doc);
}
if (removePIs) {
removePIs(doc);
}
mergeAdjacentText(doc);
}
return wrap(doc);
}
/**
* Create a NodeModel from an XML input source. By default,
* all comments and processing instruction nodes are
* stripped from the tree.
*/
static public NodeModel parse(InputSource is)
throws SAXException, IOException, ParserConfigurationException {
return parse(is, true, true);
}
/**
* Create a NodeModel from an XML file.
* @param removeComments whether to remove all comment nodes
* (recursively) from the tree before processing
* @param removePIs whether to remove all processing instruction nodes
* (recursively from the tree before processing
*/
static public NodeModel parse(File f, boolean removeComments, boolean removePIs)
throws SAXException, IOException, ParserConfigurationException {
DocumentBuilder builder = getDocumentBuilderFactory().newDocumentBuilder();
ErrorHandler errorHandler = getErrorHandler();
if (errorHandler != null) builder.setErrorHandler(errorHandler);
Document doc = builder.parse(f);
if (removeComments) {
removeComments(doc);
}
if (removePIs) {
removePIs(doc);
}
mergeAdjacentText(doc);
return wrap(doc);
}
/**
* Create a NodeModel from an XML file. By default,
* all comments and processing instruction nodes are
* stripped from the tree.
*/
static public NodeModel parse(File f)
throws SAXException, IOException, ParserConfigurationException {
return parse(f, true, true);
}
protected NodeModel(Node node) {
this.node = node;
}
/**
* @return the underling W3C DOM Node object that this TemplateNodeModel
* is wrapping.
*/
public Node getNode() {
return node;
}
public TemplateModel get(String key) throws TemplateModelException {
if (key.startsWith("@@")) {
if (key.equals("@@text")) {
return new SimpleScalar(getText(node));
}
if (key.equals("@@namespace")) {
String nsURI = node.getNamespaceURI();
return nsURI == null ? null : new SimpleScalar(nsURI);
}
if (key.equals("@@local_name")) {
String localName = node.getLocalName();
if (localName == null) {
localName = getNodeName();
}
return new SimpleScalar(localName);
}
if (key.equals("@@markup")) {
StringBuilder buf = new StringBuilder();
NodeOutputter nu = new NodeOutputter(node);
nu.outputContent(node, buf);
return new SimpleScalar(buf.toString());
}
if (key.equals("@@nested_markup")) {
StringBuilder buf = new StringBuilder();
NodeOutputter nu = new NodeOutputter(node);
nu.outputContent(node.getChildNodes(), buf);
return new SimpleScalar(buf.toString());
}
if (key.equals("@@qname")) {
String qname = getQualifiedName();
return qname == null ? null : new SimpleScalar(qname);
}
}
XPathSupport xps = getXPathSupport();
if (xps != null) {
return xps.executeQuery(node, key);
} else {
throw new TemplateModelException(
"Can't try to resolve the XML query key, because no XPath support is available. "
+ "It's either malformed or an XPath expression: " + key);
}
}
public TemplateNodeModel getParentNode() {
if (parent == null) {
Node parentNode = node.getParentNode();
if (parentNode == null) {
if (node instanceof Attr) {
parentNode = ((Attr) node).getOwnerElement();
}
}
parent = wrap(parentNode);
}
return parent;
}
public TemplateSequenceModel getChildNodes() {
if (children == null) {
children = new NodeListModel(node.getChildNodes(), this);
}
return children;
}
public final String getNodeType() throws TemplateModelException {
short nodeType = node.getNodeType();
switch (nodeType) {
case Node.ATTRIBUTE_NODE : return "attribute";
case Node.CDATA_SECTION_NODE : return "text";
case Node.COMMENT_NODE : return "comment";
case Node.DOCUMENT_FRAGMENT_NODE : return "document_fragment";
case Node.DOCUMENT_NODE : return "document";
case Node.DOCUMENT_TYPE_NODE : return "document_type";
case Node.ELEMENT_NODE : return "element";
case Node.ENTITY_NODE : return "entity";
case Node.ENTITY_REFERENCE_NODE : return "entity_reference";
case Node.NOTATION_NODE : return "notation";
case Node.PROCESSING_INSTRUCTION_NODE : return "pi";
case Node.TEXT_NODE : return "text";
}
throw new TemplateModelException("Unknown node type: " + nodeType + ". This should be impossible!");
}
public TemplateModel exec(List args) throws TemplateModelException {
if (args.size() != 1) {
throw new TemplateModelException("Expecting exactly one arguments");
}
String query = (String) args.get(0);
// Now, we try to behave as if this is an XPath expression
XPathSupport xps = getXPathSupport();
if (xps == null) {
throw new TemplateModelException("No XPath support available");
}
return xps.executeQuery(node, query);
}
public final int size() {return 1;}
public final TemplateModel get(int i) {
return i == 0 ? this : null;
}
public String getNodeNamespace() {
int nodeType = node.getNodeType();
if (nodeType != Node.ATTRIBUTE_NODE && nodeType != Node.ELEMENT_NODE) {
return null;
}
String result = node.getNamespaceURI();
if (result == null && nodeType == Node.ELEMENT_NODE) {
result = "";
} else if ("".equals(result) && nodeType == Node.ATTRIBUTE_NODE) {
result = null;
}
return result;
}
@Override
public final int hashCode() {
return node.hashCode();
}
@Override
public boolean equals(Object other) {
if (other == null) return false;
return other.getClass() == this.getClass()
&& ((NodeModel) other).node.equals(this.node);
}
static public NodeModel wrap(Node node) {
if (node == null) {
return null;
}
NodeModel result = null;
switch (node.getNodeType()) {
case Node.DOCUMENT_NODE : result = new DocumentModel((Document) node); break;
case Node.ELEMENT_NODE : result = new ElementModel((Element) node); break;
case Node.ATTRIBUTE_NODE : result = new AttributeNodeModel((Attr) node); break;
case Node.CDATA_SECTION_NODE :
case Node.COMMENT_NODE :
case Node.TEXT_NODE : result = new CharacterDataNodeModel((org.w3c.dom.CharacterData) node); break;
case Node.PROCESSING_INSTRUCTION_NODE : result = new PINodeModel((ProcessingInstruction) node); break;
case Node.DOCUMENT_TYPE_NODE : result = new DocumentTypeModel((DocumentType) node); break;
}
return result;
}
/**
* Recursively removes all comment nodes
* from the subtree.
*
* @see #simplify
*/
static public void removeComments(Node node) {
NodeList children = node.getChildNodes();
int i = 0;
int len = children.getLength();
while (i < len) {
Node child = children.item(i);
if (child.hasChildNodes()) {
removeComments(child);
i++;
} else {
if (child.getNodeType() == Node.COMMENT_NODE) {
node.removeChild(child);
len--;
} else {
i++;
}
}
}
}
/**
* Recursively removes all processing instruction nodes
* from the subtree.
*
* @see #simplify
*/
static public void removePIs(Node node) {
NodeList children = node.getChildNodes();
int i = 0;
int len = children.getLength();
while (i < len) {
Node child = children.item(i);
if (child.hasChildNodes()) {
removePIs(child);
i++;
} else {
if (child.getNodeType() == Node.PROCESSING_INSTRUCTION_NODE) {
node.removeChild(child);
len--;
} else {
i++;
}
}
}
}
/**
* Merges adjacent text/cdata nodes, so that there are no
* adjacent text/cdata nodes. Operates recursively
* on the entire subtree. You thus lose information
* about any CDATA sections occurring in the doc.
*
* @see #simplify
*/
static public void mergeAdjacentText(Node node) {
Node child = node.getFirstChild();
while (child != null) {
if (child instanceof Text || child instanceof CDATASection) {
Node next = child.getNextSibling();
if (next instanceof Text || next instanceof CDATASection) {
String fullText = child.getNodeValue() + next.getNodeValue();
((CharacterData) child).setData(fullText);
node.removeChild(next);
}
} else {
mergeAdjacentText(child);
}
child = child.getNextSibling();
}
}
/**
* Removes comments and processing instruction, and then unites adjacent text nodes.
* Note that CDATA sections count as text nodes.
*/
static public void simplify(Node node) {
NodeList children = node.getChildNodes();
int i = 0;
int len = children.getLength();
Node prevTextChild = null;
while (i < len) {
Node child = children.item(i);
if (child.hasChildNodes()) {
simplify(child);
prevTextChild = null;
i++;
} else {
int type = child.getNodeType();
if (type == Node.PROCESSING_INSTRUCTION_NODE) {
node.removeChild(child);
len--;
} else if (type == Node.COMMENT_NODE) {
node.removeChild(child);
len--;
} else if (type == Node.TEXT_NODE || type == Node.CDATA_SECTION_NODE ) {
if (prevTextChild != null) {
CharacterData ptc = (CharacterData) prevTextChild;
ptc.setData(ptc.getNodeValue() + child.getNodeValue());
node.removeChild(child);
len--;
} else {
prevTextChild = child;
i++;
}
} else {
prevTextChild = null;
i++;
}
}
}
}
NodeModel getDocumentNodeModel() {
if (node instanceof Document) {
return this;
} else {
return wrap(node.getOwnerDocument());
}
}
/**
* Tells the system to use (restore) the default (initial) XPath system used by
* this FreeMarker version on this system.
*/
static public void useDefaultXPathSupport() {
synchronized (STATIC_LOCK) {
xpathSupportClass = null;
jaxenXPathSupport = null;
try {
useXalanXPathSupport();
} catch (Exception e) {
; // ignore
}
if (xpathSupportClass == null) try {
useSunInternalXPathSupport();
} catch (Exception e) {
; // ignore
}
if (xpathSupportClass == null) try {
useJaxenXPathSupport();
} catch (Exception e) {
; // ignore
}
}
}
/**
* Convenience method. Tells the system to use Jaxen for XPath queries.
* @throws Exception if the Jaxen classes are not present.
*/
static public void useJaxenXPathSupport() throws Exception {
Class.forName("org.jaxen.dom.DOMXPath");
Class c = Class.forName("freemarker.ext.dom.JaxenXPathSupport");
jaxenXPathSupport = (XPathSupport) c.newInstance();
synchronized (STATIC_LOCK) {
xpathSupportClass = c;
}
if (LOG.isDebugEnabled()) {
LOG.debug("Using Jaxen classes for XPath support");
}
}
/**
* Convenience method. Tells the system to use Xalan for XPath queries.
* @throws Exception if the Xalan XPath classes are not present.
*/
static public void useXalanXPathSupport() throws Exception {
Class.forName("org.apache.xpath.XPath");
Class c = Class.forName("freemarker.ext.dom.XalanXPathSupport");
synchronized (STATIC_LOCK) {
xpathSupportClass = c;
}
if (LOG.isDebugEnabled()) {
LOG.debug("Using Xalan classes for XPath support");
}
}
static public void useSunInternalXPathSupport() throws Exception {
Class.forName("com.sun.org.apache.xpath.internal.XPath");
Class c = Class.forName("freemarker.ext.dom.SunInternalXalanXPathSupport");
synchronized (STATIC_LOCK) {
xpathSupportClass = c;
}
if (LOG.isDebugEnabled()) {
LOG.debug("Using Sun's internal Xalan classes for XPath support");
}
}
/**
* Set an alternative implementation of freemarker.ext.dom.XPathSupport to use
* as the XPath engine.
* @param cl the class, or <code>null</code> to disable XPath support.
*/
static public void setXPathSupportClass(Class cl) {
if (cl != null && !XPathSupport.class.isAssignableFrom(cl)) {
throw new RuntimeException("Class " + cl.getName()
+ " does not implement freemarker.ext.dom.XPathSupport");
}
synchronized (STATIC_LOCK) {
xpathSupportClass = cl;
}
}
/**
* Get the currently used freemarker.ext.dom.XPathSupport used as the XPath engine.
* Returns <code>null</code> if XPath support is disabled.
*/
static public Class getXPathSupportClass() {
synchronized (STATIC_LOCK) {
return xpathSupportClass;
}
}
static private String getText(Node node) {
String result = "";
if (node instanceof Text || node instanceof CDATASection) {
result = ((org.w3c.dom.CharacterData) node).getData();
} else if (node instanceof Element) {
NodeList children = node.getChildNodes();
for (int i = 0; i < children.getLength(); i++) {
result += getText(children.item(i));
}
} else if (node instanceof Document) {
result = getText(((Document) node).getDocumentElement());
}
return result;
}
XPathSupport getXPathSupport() {
if (jaxenXPathSupport != null) {
return jaxenXPathSupport;
}
XPathSupport xps = null;
Document doc = node.getOwnerDocument();
if (doc == null) {
doc = (Document) node;
}
synchronized (doc) {
WeakReference ref = (WeakReference) xpathSupportMap.get(doc);
if (ref != null) {
xps = (XPathSupport) ref.get();
}
if (xps == null) {
try {
xps = (XPathSupport) xpathSupportClass.newInstance();
xpathSupportMap.put(doc, new WeakReference(xps));
} catch (Exception e) {
LOG.error("Error instantiating xpathSupport class", e);
}
}
}
return xps;
}
String getQualifiedName() throws TemplateModelException {
return getNodeName();
}
public Object getAdaptedObject(Class hint) {
return node;
}
public Object getWrappedObject() {
return node;
}
public Object[] explainTypeError(Class[] expectedClasses) {
for (int i = 0; i < expectedClasses.length; i++) {
Class expectedClass = expectedClasses[i];
if (TemplateDateModel.class.isAssignableFrom(expectedClass)
|| TemplateNumberModel.class.isAssignableFrom(expectedClass)
|| TemplateBooleanModel.class.isAssignableFrom(expectedClass)) {
return new Object[] {
"XML node values are always strings (text), that is, they can't be used as number, "
+ "date/time/datetime or boolean without explicit conversion (such as "
+ "someNode?number, someNode?datetime.xs, someNode?date.xs, someNode?time.xs, "
+ "someNode?boolean).",
};
}
}
return null;
}
}