/*
* $Id: CachingLocaleUrlDefinitionDAO.java 784982 2009-06-15 21:12:59Z apetrelli $
*
* 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.definition.dao;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import org.apache.tiles.Attribute;
import org.apache.tiles.Definition;
import org.apache.tiles.definition.DefinitionsFactoryException;
import org.apache.tiles.definition.NoSuchDefinitionException;
import org.apache.tiles.definition.Refreshable;
import org.apache.tiles.util.LocaleUtil;
import org.apache.tiles.util.WildcardHelper;
/**
* <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>
*
* @version $Rev: 784982 $ $Date: 2009-06-15 23:12:59 +0200 (lun, 15 giu 2009) $
* @since 2.1.0
*/
public class CachingLocaleUrlDefinitionDAO extends BaseLocaleUrlDefinitionDAO
implements Refreshable {
/**
* 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;
/**
* An object that helps in resolving definitions with wildcards.
*
* @since 2.1.0
*/
protected WildcardHelper wildcardHelper = new WildcardHelper();
/**
* Stores patterns depending on the locale they refer to.
*
* @since 2.1.0
*/
protected Map<Locale, List<WildcardMapping>> localePatternPaths =
new HashMap<Locale, List<WildcardMapping>>();
/**
* Constructor.
*
* @since 2.1.0
*/
public CachingLocaleUrlDefinitionDAO() {
locale2definitionMap = new HashMap<Locale, Map<String, Definition>>();
}
/** {@inheritDoc} */
@Override
public void init(Map<String, String> params) {
super.init(params);
String param = params.get(CHECK_REFRESH_INIT_PARAMETER);
checkRefresh = "true".equals(param);
}
/** {@inheritDoc} */
public Definition getDefinition(String name, Locale customizationKey) {
Definition retValue = null;
if (customizationKey == null) {
customizationKey = LocaleUtil.NULL_LOCALE;
}
Map<String, Definition> definitions = getDefinitions(customizationKey);
if (definitions != null) {
retValue = definitions.get(name);
if (retValue == null
&& localePatternPaths.containsKey(customizationKey)) {
retValue = resolveWildcardDefinition(localePatternPaths
.get(customizationKey), name);
if (retValue != null) {
try {
synchronized (definitions) {
definitions.put(name, retValue);
}
} catch (NoSuchDefinitionException ex) {
throw new IllegalStateException("Unable to resolve wildcard mapping", ex);
}
}
}
}
return retValue;
}
/** {@inheritDoc} */
public Map<String, Definition> getDefinitions(Locale customizationKey) {
if (customizationKey == null) {
customizationKey = LocaleUtil.NULL_LOCALE;
}
Map<String, Definition> retValue = locale2definitionMap
.get(customizationKey);
if (retValue == null || (checkRefresh && refreshRequired())) {
retValue = checkAndloadDefinitions(customizationKey);
}
return retValue;
}
/** {@inheritDoc} */
public synchronized void refresh() {
if (refreshRequired()) {
locale2definitionMap.clear();
}
}
/**
* Sets the flag to check URL refresh. If not called, the default is
* <code>false</code>.
*
* @param checkRefresh When <code>true</code>, enables automatic checking
* of URLs changing.
* @since 2.1.0
*/
public void setCheckRefresh(boolean checkRefresh) {
this.checkRefresh = checkRefresh;
}
/**
* Checks if URLs have changed. If yes, it clears the cache. Then continues
* loading definitions.
*
* @param customizationKey The locale to use when loading URLs.
* @return The loaded definitions.
* @since 2.1.0
*/
protected synchronized Map<String, Definition> checkAndloadDefinitions(
Locale customizationKey) {
if (checkRefresh && refreshRequired()) {
locale2definitionMap.clear();
}
return loadDefinitions(customizationKey);
}
/**
* Tries to load definitions if necessary.
*
* @param customizationKey The locale to use when loading URLs.
* @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;
}
localeDefsMap = loadDefinitionsFromURLs(customizationKey);
return localeDefsMap;
}
/**
* Loads definitions from the URLs.
*
* @param customizationKey The locale to use when loading URLs.
* @return The loaded definitions.
* @since 2.1.0
*/
protected Map<String, Definition> loadDefinitionsFromURLs(Locale customizationKey) {
Map<String, Definition> localeDefsMap = loadRawDefinitionsFromURLs(customizationKey);
postDefinitionLoadOperations(localeDefsMap, customizationKey);
return localeDefsMap;
}
/**
* Loads the raw definitions from the URLs associated with a locale.
*
* @param customizationKey The locale to use when loading URLs.
* @return The loaded definitions.
* @since 2.1.3
*/
protected Map<String, Definition> loadRawDefinitionsFromURLs(
Locale customizationKey) {
Map<String, Definition> localeDefsMap;
String postfix = LocaleUtil.calculatePostfix(customizationKey);
Locale parentLocale = LocaleUtil.getParentLocale(customizationKey);
localeDefsMap = new LinkedHashMap<String, Definition>();
if (parentLocale != null) {
Map<String, Definition> parentDefs = loadParentDefinitions(parentLocale);
if (parentDefs != null) {
localeDefsMap.putAll(parentDefs);
}
}
// For each source, the URL must be loaded.
for (URL url : sourceURLs) {
String path = url.toExternalForm();
String newPath = LocaleUtil.concatPostfix(path, postfix);
try {
URL newUrl = new URL(newPath);
Map<String, Definition> defsMap = loadDefinitionsFromURL(newUrl);
if (defsMap != null) {
localeDefsMap.putAll(defsMap);
}
} catch (MalformedURLException e) {
throw new DefinitionsFactoryException("Error parsing URL "
+ newPath, e);
}
}
locale2definitionMap.put(customizationKey, localeDefsMap);
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);
}
/**
* Operations to be done after definitions are loaded.
*
* @param localeDefsMap The loaded definitions.
* @param customizationKey The locale to use when loading URLs.
* @since 2.1.0
*/
protected void postDefinitionLoadOperations(
Map<String, Definition> localeDefsMap, Locale customizationKey) {
List<WildcardMapping> lpaths = localePatternPaths
.get(customizationKey);
if (lpaths == null) {
lpaths = new ArrayList<WildcardMapping>();
localePatternPaths.put(customizationKey, lpaths);
}
addWildcardPaths(lpaths, localeDefsMap);
}
/**
* Adds wildcard paths that are stored inside a normal definition map.
*
* @param paths The list containing the currently stored paths.
* @param defsMap The definition map to parse.
* @since 2.1.0
*/
protected void addWildcardPaths(List<WildcardMapping> paths,
Map<String, Definition> defsMap) {
for (Map.Entry<String, Definition> de : defsMap.entrySet()) {
if (de.getKey().
indexOf('*') != -1) {
paths.add(new WildcardMapping(de.getKey(), de.getValue()));
}
}
}
/**
* Try to resolve a wildcard definition.
*
* @param paths The list containing the currently stored paths.
* @param name The name of the definition to resolve.
* @return A definition, if found, or <code>null</code> if not.
* @since 2.1.0
*/
protected Definition resolveWildcardDefinition(
List<WildcardMapping> paths, String name) {
Map<Integer, String> vars = new HashMap<Integer, String>();
Definition d = null;
for (WildcardMapping wm : paths) {
if (wildcardHelper.match(vars, name, wm.getPattern())) {
d = replaceDefinition(wm.getDefinition(), name, vars);
break;
}
}
return d;
}
/**
* Creates a definition given its representation with wildcards.
*
* @param d The definition to replace.
* @param name The name of the definition to be created.
* @param vars The variables to be substituted.
* @return The definition that can be rendered.
* @since 2.1.0
*/
protected Definition replaceDefinition(Definition d, String name,
Map<Integer, String> vars) {
Definition nudef = new Definition();
nudef.setExtends(replace(d.getExtends(), vars));
nudef.setName(name);
nudef.setPreparer(replace(d.getPreparer(), vars));
nudef.setTemplateAttribute(replaceVarsInAttribute(d
.getTemplateAttribute(), vars));
Set<String> localAttributeNames = d.getLocalAttributeNames();
if (localAttributeNames != null && !localAttributeNames.isEmpty()) {
for (String attributeName : localAttributeNames) {
Attribute attr = d.getLocalAttribute(attributeName);
Attribute nuattr = replaceVarsInAttribute(attr, vars);
nudef.putAttribute(replace(attributeName, vars), nuattr);
}
}
return nudef;
}
/**
* Replaces variables into an attribute.
*
* @param attr The attribute to be used as a basis, containing placeholders
* for variables.
* @param vars The variables to replace.
* @return A new instance of an attribute, whose properties have been
* replaced with variables' values.
*/
private Attribute replaceVarsInAttribute(Attribute attr,
Map<Integer, String> vars) {
Attribute nuattr = new Attribute();
nuattr.setRole(replace(attr.getRole(), vars));
nuattr.setRenderer(attr.getRenderer());
nuattr.setExpression(attr.getExpression());
Object value = attr.getValue();
if (value instanceof String) {
value = replace((String) value, vars);
}
nuattr.setValue(value);
return nuattr;
}
/**
* Replaces a string with placeholders using values of a variable map.
*
* @param st The string to replace.
* @param vars The variables.
* @return The replaced string.
* @since 2.1.0
*/
protected String replace(String st, Map<Integer, String> vars) {
return org.apache.tiles.util.WildcardHelper.convertParam(st, vars);
}
/**
* Maps a pattern with a definition in cache.
*
* @since 2.1.0
*/
protected class WildcardMapping {
/**
* The compiled pattern.
*/
private int[] pattern;
/**
* The definition that matches the pattern.
*/
private Definition definition;
/**
* Constructor.
*
* @param pattern The compiled pattern.
* @param definition A definition that matches the pattern.
*
* @since 2.1.0
*/
public WildcardMapping(String pattern, Definition definition) {
this.pattern = wildcardHelper.compilePattern(pattern);
this.definition = definition;
}
/**
* Returns the definition.
*
* @return The definition.
* @since 2.1.0
*/
public Definition getDefinition() {
return definition;
}
/**
* Returns the compiled pattern.
*
* @return The pattern.
* @since 2.1.0
*/
public int[] getPattern() {
return pattern;
}
}
}