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Modern server-side Java template engine for both web and standalone environments
/*
* =============================================================================
*
* Copyright (c) 2011, The THYMELEAF team (http://www.thymeleaf.org)
*
* 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 org.thymeleaf;
import java.util.Set;
import org.thymeleaf.exceptions.ParsingException;
import org.thymeleaf.processor.attr.IAttrProcessor;
import org.thymeleaf.processor.tag.ITagProcessor;
import org.thymeleaf.util.Validate;
import org.w3c.dom.Attr;
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;
/**
*
* Preprocess template DOM, setting executability flags where required.
*
*
* During cache storage of a template, all nodes in the template's DOM are scanned
* in order to detect which ones the engine can safely skip during normal operation, and
* flags are set consequently.
*
*
* @author Daniel Fernández
*
* @since 1.1
*
*/
final class DOMDocumentPreprocessor {
/**
*
* Preprocesses the (recently parsed) document,
* setting executability flags as appropiate for each node.
*
*
* @param configuration the configuration currently being used for the Template Engine.
* @param document the document to be preprocessed
*/
static void preprocess(
final Configuration configuration, final Document document) {
Validate.notNull(configuration, "Configuration cannot be null");
Validate.notNull(document, "Document cannot be null");
Element rootElement = null;
final NodeList docChildren = document.getChildNodes();
if (docChildren.getLength() < 1) {
throw new ParsingException(
"Invalid document structure: no root element found.");
}
if (docChildren.getLength() == 1) {
rootElement = (Element) docChildren.item(0);
} else if (docChildren.getLength() >= 2) {
for (int i = 1; rootElement == null && i < docChildren.getLength(); i++) {
if (docChildren.item(i).getNodeType() == Node.ELEMENT_NODE) {
rootElement = (Element) docChildren.item(i);
}
}
if (rootElement == null) {
throw new ParsingException(
"Invalid document structure: No valid root element found.");
}
} else {
throw new ParsingException(
"Invalid document structure: No more than two top-level elements are allowed " +
"(either root element, or doctype + root element).");
}
unsafePreprocessNode(configuration, rootElement);
}
private static boolean unsafePreprocessNode(
final Configuration configuration, final Node node) {
if (node.getNodeType() == Node.ELEMENT_NODE) {
boolean isNodeExecutable = false;
final Element element = (Element) node;
final String elementName = element.getNodeName();
final Set dialectsForTagName =
configuration.getDialectsForTagName(elementName);
if (dialectsForTagName != null) {
// This tag name is (potentially) processed by some of our dialects
final ITagProcessor elementProcessor = configuration.getTagProcessor(dialectsForTagName, element);
if (elementProcessor != null) {
isNodeExecutable = true;
}
}
if (!isNodeExecutable) {
final NamedNodeMap attributes = element.getAttributes();
for (int i = 0; !isNodeExecutable && i < attributes.getLength(); i++) {
final Attr attribute = (Attr) attributes.item(i);
final String attributeName = attribute.getName();
final Set dialectsForAttrName =
configuration.getDialectsForAttrName(attributeName);
if (dialectsForAttrName != null) {
// This attr name is (potentially) processed by some of our dialects
final IAttrProcessor attrProcessor = configuration.getAttrProcessor(dialectsForAttrName, element, attribute);
if (attrProcessor != null) {
isNodeExecutable = true;
}
}
}
}
if (!isNodeExecutable) {
// We already know this node is not executable.
DOMExecution.setExecutableNode(node, false);
}
/*
* Scan the node's children
*/
boolean isTreeExecutable = isNodeExecutable;
final NodeList children = node.getChildNodes();
for (int i = 0; i < children.getLength(); i++) {
if (unsafePreprocessNode(configuration, children.item(i))) {
// Tree is executable when at least one child is executable
isTreeExecutable = true;
}
}
if (!isTreeExecutable) {
// There is nothing to execute in this whole tree
DOMExecution.setExecutableTree(node, false);
}
return isTreeExecutable;
}
/*
* By default, any non-element node is non-executable.
*
* The only special case in which it could be executable is when an inliner has been
* set for any of its parents. But in that case, the processor setting the inliner
* should have cleared the "executability" flag for all the children of the
* tag that the inliner is being set at.
*/
DOMExecution.setExecutableNode(node, false);
return false;
}
}
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