CachingLocaleUrlDefinitionDAO.java
/*
* 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.tiles.core.definition.dao;
import org.apache.tiles.api.Definition;
import org.apache.tiles.core.definition.pattern.PatternDefinitionResolver;
import org.apache.tiles.core.definition.pattern.PatternDefinitionResolverAware;
import org.apache.tiles.request.ApplicationContext;
import org.apache.tiles.request.ApplicationResource;
import org.apache.tiles.request.locale.LocaleUtil;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Locale;
import java.util.Map;
/**
* <p>
* A definitions DAO (loading URLs and using Locale as a customization key) that
* caches definitions that have been loaded in a raw way (i.e. with inheritance
* that is not resolved).
* </p>
* <p>
* It can check if the URLs change, but by default this feature is turned off.
* </p>
*
* @since 2.1.0
*/
public class CachingLocaleUrlDefinitionDAO extends BaseLocaleUrlDefinitionDAO implements PatternDefinitionResolverAware<Locale> {
/**
* Initialization parameter to set whether we want to refresh URLs when they
* change.
*
* @since 2.1.0
*/
public static final String CHECK_REFRESH_INIT_PARAMETER = "org.apache.tiles.definition.dao.LocaleUrlDefinitionDAO.CHECK_REFRESH";
/**
* The locale-specific set of definitions objects.
*
* @since 2.1.0
*/
protected Map<Locale, Map<String, Definition>> locale2definitionMap;
/**
* Flag that, when <code>true</code>, enables automatic checking of URLs
* changing.
*
* @since 2.1.0
*/
protected boolean checkRefresh = false;
/**
* Resolves definitions using patterns.
*
* @since 2.2.0
*/
protected PatternDefinitionResolver<Locale> definitionResolver;
/**
* Constructor.
*
* @since 2.1.0
*/
public CachingLocaleUrlDefinitionDAO(ApplicationContext applicationContext) {
super(applicationContext);
locale2definitionMap = new HashMap<>();
}
/**
* {@inheritDoc}
*/
public void setPatternDefinitionResolver(
PatternDefinitionResolver<Locale> definitionResolver) {
this.definitionResolver = definitionResolver;
}
/**
* {@inheritDoc}
*/
public Definition getDefinition(String name, Locale customizationKey) {
Definition retValue = null;
if (customizationKey == null) {
customizationKey = Locale.ROOT;
}
Map<String, Definition> definitions = getDefinitions(customizationKey);
if (definitions != null) {
retValue = definitions.get(name);
if (retValue == null) {
retValue = getDefinitionFromResolver(name, customizationKey);
if (retValue != null) {
synchronized (definitions) {
definitions.put(name, retValue);
}
}
}
}
return retValue;
}
/**
* {@inheritDoc}
*/
public Map<String, Definition> getDefinitions(Locale customizationKey) {
if (customizationKey == null) {
customizationKey = Locale.ROOT;
}
Map<String, Definition> retValue = locale2definitionMap
.get(customizationKey);
if (retValue == null || (checkRefresh && refreshRequired())) {
retValue = checkAndloadDefinitions(customizationKey);
}
return retValue;
}
/**
* Sets the flag to check source refresh. If not called, the default is
* <code>false</code>.
*
* @param checkRefresh When <code>true</code>, enables automatic checking
* of sources changing.
* @since 2.1.0
*/
public void setCheckRefresh(boolean checkRefresh) {
this.checkRefresh = checkRefresh;
}
/**
* Returns a definition from the definition resolver.
*
* @param name The name of the definition.
* @param customizationKey The customization key to use.
* @return The resolved definition.
*/
protected Definition getDefinitionFromResolver(String name,
Locale customizationKey) {
return definitionResolver.resolveDefinition(name,
customizationKey);
}
/**
* Checks if sources have changed. If yes, it clears the cache. Then continues
* loading definitions.
*
* @param customizationKey The locale to use when loading sources.
* @return The loaded definitions.
* @since 2.1.0
*/
protected synchronized Map<String, Definition> checkAndloadDefinitions(Locale customizationKey) {
Map<String, Definition> existingDefinitions = locale2definitionMap.get(customizationKey);
boolean definitionsAlreadyLoaded = existingDefinitions != null;
if (definitionsAlreadyLoaded) {
return existingDefinitions;
}
if (checkRefresh && refreshRequired()) {
locale2definitionMap.clear();
definitionResolver.clearPatternPaths(customizationKey);
}
loadDefinitions(customizationKey);
return locale2definitionMap.get(customizationKey);
}
/**
* Tries to load definitions if necessary.
*
* @param customizationKey The locale to use when loading sources.
* @return The loaded definitions.
* @since 2.1.0
*/
protected Map<String, Definition> loadDefinitions(Locale customizationKey) {
Map<String, Definition> localeDefsMap = locale2definitionMap
.get(customizationKey);
if (localeDefsMap != null) {
return localeDefsMap;
}
return loadDefinitionsFromResources(customizationKey);
}
/**
* Loads definitions from the sources.
*
* @param customizationKey The locale to use when loading Resources.
* @return The loaded definitions.
* @since 2.1.0
*/
protected Map<String, Definition> loadDefinitionsFromResources(Locale customizationKey) {
Map<String, Definition> localeDefsMap = loadRawDefinitionsFromResources(customizationKey);
Map<String, Definition> defsMap = definitionResolver
.storeDefinitionPatterns(copyDefinitionMap(localeDefsMap),
customizationKey);
locale2definitionMap.put(customizationKey, defsMap);
return localeDefsMap;
}
/**
* Loads the raw definitions from the sources associated with a locale.
*
* @param customizationKey The locale to use when loading Resources.
* @return The loaded definitions.
* @since 2.1.3
*/
protected Map<String, Definition> loadRawDefinitionsFromResources(Locale customizationKey) {
Map<String, Definition> localeDefsMap;
Locale parentLocale = LocaleUtil.getParentLocale(customizationKey);
localeDefsMap = new LinkedHashMap<>();
if (parentLocale != null) {
Map<String, Definition> parentDefs = loadRawDefinitionsFromResources(parentLocale);
if (parentDefs != null) {
localeDefsMap.putAll(parentDefs);
}
}
// For each source, the resource must be loaded.
for (ApplicationResource resource : sources) {
ApplicationResource newResource = applicationContext.getResource(resource, customizationKey);
if (newResource != null) {
Map<String, Definition> defsMap = loadDefinitionsFromResource(newResource);
if (defsMap != null) {
localeDefsMap.putAll(defsMap);
}
}
}
return localeDefsMap;
}
/**
* Loads parent definitions, i.e. definitions mapped to a parent locale.
*
* @param parentLocale The locale to use when loading URLs.
* @return The loaded parent definitions.
* @since 2.1.0
*/
protected Map<String, Definition> loadParentDefinitions(Locale parentLocale) {
return loadDefinitions(parentLocale);
}
/**
* Copies the definition map to be passed to a higher level of customization
* key.
*
* @param localeDefsMap The map of definition to be copied.
* @return The copy of the definition map. This particular implementation
* return the <code>localeDefsMap</code> itself.
* @since 2.1.4
*/
protected Map<String, Definition> copyDefinitionMap(
Map<String, Definition> localeDefsMap) {
return localeDefsMap;
}
}