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XML/XHTML/HTML5 template engine for Java
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/*
* =============================================================================
*
* Copyright (c) 2011-2013, 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.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.thymeleaf.cache.ICache;
import org.thymeleaf.cache.ICacheManager;
import org.thymeleaf.dom.Document;
import org.thymeleaf.dom.Node;
import org.thymeleaf.exceptions.TemplateInputException;
import org.thymeleaf.resourceresolver.IResourceResolver;
import org.thymeleaf.templatemode.ITemplateModeHandler;
import org.thymeleaf.templateparser.ITemplateParser;
import org.thymeleaf.templateresolver.ITemplateResolver;
import org.thymeleaf.templateresolver.TemplateResolution;
import org.thymeleaf.util.StringUtils;
import org.thymeleaf.util.Validate;
/**
*
* The template repository is an internal utility class that is responsible before the
* Template Engine of retrieving templates (parsed) and fragments, performing all the necessary
* operations against the caches in order to obtain the required data.
*
*
* Each {@link TemplateEngine} uses a single object of this class.
*
*
* @author Daniel Fernández
*
* @since 2.0.0
*
*/
public final class TemplateRepository {
private static final Logger logger = LoggerFactory.getLogger(TemplateRepository.class);
private final ICache templateCache; // might be null! (= no cache)
private final ICache> fragmentCache; // might be null! (= no cache)
private final Map parsersByTemplateMode;
/**
*
* This constructor should only be called directly for
testing purposes
.
*
*
* @param configuration the configuration being currently used.
*/
public TemplateRepository(final Configuration configuration) {
super();
Validate.notNull(configuration, "Configuration object cannot be null");
final ICacheManager cacheManager = configuration.getCacheManager();
if (cacheManager == null) {
this.templateCache = null;
this.fragmentCache = null;
} else {
this.templateCache = cacheManager.getTemplateCache();
this.fragmentCache = cacheManager.getFragmentCache();
}
this.parsersByTemplateMode = new HashMap(10, 1.0f);
for (final ITemplateModeHandler handler : configuration.getTemplateModeHandlers()) {
this.parsersByTemplateMode.put(handler.getTemplateModeName(), handler.getTemplateParser());
}
}
/**
*
* Clears the template cache.
*
*/
public void clearTemplateCache() {
if (this.templateCache != null) {
this.templateCache.clear();
}
}
/**
*
* Clears any existing entries for template of the specified
* name at the template cache.
*
*
* @param templateName the name of the template whose entries have to be cleared.
*/
public void clearTemplateCacheFor(final String templateName) {
if (this.templateCache != null) {
this.templateCache.clearKey(templateName);
}
}
/**
*
* Clears the fragments cache.
*
*/
public void clearFragmentCache() {
if (this.fragmentCache != null) {
this.fragmentCache.clear();
}
}
/**
*
* Clears a specific entry at the fragment cache.
*
*
* @param fragment the fragment to be cleared.
*/
public void clearFragmentCacheFor(final String fragment) {
if (this.fragmentCache != null) {
this.fragmentCache.clearKey(fragment);
}
}
/**
*
* Obtains a template. This method is responsible of providing a {@link Template} to the
* {@link TemplateEngine} by following these steps:
*
*
* - Try to get the template from the cache (if it exists).
* - Querying all the configured {@link ITemplateResolver} objects until one of them resolves
* the template.
* - If resolved, use the associated {@link IResourceResolver} object to obtain an {@link InputStream}
* on it.
* - Obtain the {@link ITemplateModeHandler} object associated to the template mode assigned
* to the resolved template (by the template resolver).
* - Use the {@link ITemplateParser} of the selected {@link ITemplateModeHandler} to read and
* parse the template into a {@link Document}.
* - If required and allowed by configuration, put the resolved template into the cache.
*
*
* @param templateProcessingParameters the parameters object containing all the necessary pieces of
* data in order to adequately resolve the template.
* @return the resolved and parsed Template.
*/
public Template getTemplate(final TemplateProcessingParameters templateProcessingParameters) {
Validate.notNull(templateProcessingParameters, "Template Processing Parameters cannot be null");
final String templateName = templateProcessingParameters.getTemplateName();
if (this.templateCache != null) {
final Template cached =
this.templateCache.get(templateName);
if (cached != null) {
return cached.createDuplicate();
}
}
final Configuration configuration = templateProcessingParameters.getConfiguration();
final Set templateResolvers = configuration.getTemplateResolvers();
TemplateResolution templateResolution = null;
InputStream templateInputStream = null;
for (final ITemplateResolver templateResolver : templateResolvers) {
templateResolution = templateResolver.resolveTemplate(templateProcessingParameters);
if (templateResolution != null) {
final String resourceName = templateResolution.getResourceName();
final IResourceResolver resourceResolver = templateResolution.getResourceResolver();
if (logger.isTraceEnabled()) {
logger.trace("[THYMELEAF][{}] Trying to resolve template \"{}\" as resource \"{}\" with resource resolver \"{}\"", new Object[] {TemplateEngine.threadIndex(), templateName, resourceName, resourceResolver.getName()});
}
templateInputStream =
resourceResolver.getResourceAsStream(templateProcessingParameters, resourceName);
if (templateInputStream == null) {
if (logger.isTraceEnabled()) {
logger.trace("[THYMELEAF][{}] Template \"{}\" could not be resolved as resource \"{}\" with resource resolver \"{}\"", new Object[] {TemplateEngine.threadIndex(), templateName, resourceName, resourceResolver.getName()});
}
} else {
if (logger.isDebugEnabled()) {
logger.debug("[THYMELEAF][{}] Template \"{}\" was correctly resolved as resource \"{}\" in mode {} with resource resolver \"{}\"", new Object[] {TemplateEngine.threadIndex(), templateName, resourceName, templateResolution.getTemplateMode(), resourceResolver.getName()});
}
break;
}
} else {
if (logger.isTraceEnabled()) {
logger.trace("[THYMELEAF][{}] Skipping template resolver \"{}\" for template \"{}\"", new Object[] {TemplateEngine.threadIndex(), templateResolver.getName(), templateName});
}
}
}
if (templateResolution == null || templateInputStream == null) {
throw new TemplateInputException(
"Error resolving template \"" + templateProcessingParameters.getTemplateName() + "\", " +
"template might not exist or might not be accessible by " +
"any of the configured Template Resolvers");
}
final String templateMode = templateResolution.getTemplateMode();
final ITemplateParser templateParser = this.parsersByTemplateMode.get(templateMode);
if (templateParser == null) {
throw new TemplateInputException(
"Template mode \"" + templateMode + "\" has not been configured");
}
if (logger.isTraceEnabled()) {
logger.trace("[THYMELEAF][{}] Starting parsing of template \"{}\"", TemplateEngine.threadIndex(), templateName);
}
final String characterEncoding = templateResolution.getCharacterEncoding();
Reader reader = null;
if (!StringUtils.isEmptyOrWhitespace(characterEncoding)) {
try {
reader = new InputStreamReader(templateInputStream, characterEncoding);
} catch (final UnsupportedEncodingException e) {
throw new TemplateInputException("Exception parsing document", e);
}
} else {
reader = new InputStreamReader(templateInputStream);
}
final Document document =
templateParser.parseTemplate(configuration, templateName, reader);
if (logger.isTraceEnabled()) {
logger.trace("[THYMELEAF][{}] Finished parsing of template \"{}\"", TemplateEngine.threadIndex(), templateName);
}
document.precompute(configuration);
final Template template =
new Template(templateName, templateResolution, document);
if (this.templateCache != null) {
if (templateResolution.getValidity().isCacheable()) {
this.templateCache.put(templateName, template);
return template.createDuplicate();
}
}
return template;
}
/**
*
* Obtains a fragment. A fragment is a piece of template code that is usually
* read from a different source and needs parsing for converting it into a DOM subtree.
*
*
* Common examples of fragments are the messages in a Messages.properties
* file that contain tags like <strong> <u>, etc. and are included in thymeleaf
* templates via an attribute like th:utext.
*
*
* @param arguments the execution arguments
* @param fragment the fragment to be processed
* @return the result of processing the fragment: a list of {@link Node} that can be linked
* to the DOM being processed.
*/
public List getFragment(final Arguments arguments, final String fragment) {
Validate.notNull(arguments, "Arguments cannot be null");
Validate.notNull(fragment, "Fragment cannot be null");
final String templateMode = arguments.getTemplateResolution().getTemplateMode();
final String cacheKey = computeFragmentCacheKey(templateMode, fragment);
if (this.fragmentCache != null) {
final List fragmentNodes = this.fragmentCache.get(cacheKey);
if (fragmentNodes != null) {
return cloneFragmentNodes(fragmentNodes);
}
}
final Configuration configuration = arguments.getConfiguration();
final ITemplateParser templateParser =
configuration.getTemplateModeHandler(templateMode).getTemplateParser();
final List fragmentNodes = templateParser.parseFragment(configuration, fragment);
if (this.fragmentCache != null) {
this.fragmentCache.put(cacheKey, fragmentNodes);
return cloneFragmentNodes(fragmentNodes);
}
return fragmentNodes;
}
private static String computeFragmentCacheKey(final String templateMode, final String fragment) {
return '{' + templateMode + '}' + fragment;
}
private static List cloneFragmentNodes(final List fragmentNodes) {
if (fragmentNodes == null) {
return null;
}
final List clonedNodes = new ArrayList(fragmentNodes.size() + 2);
for (final Node fragmentNode : fragmentNodes) {
clonedNodes.add(fragmentNode.cloneNode(null, false));
}
return clonedNodes;
}
}