org.springframework.context.support.ResourceBundleMessageSource Maven / Gradle / Ivy
/*
* Copyright 2002-2016 the original author or authors.
*
* 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.springframework.context.support;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.net.URLConnection;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.PropertyResourceBundle;
import java.util.ResourceBundle;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
/**
* {@link org.springframework.context.MessageSource} implementation that
* accesses resource bundles using specified basenames. This class relies
* on the underlying JDK's {@link java.util.ResourceBundle} implementation,
* in combination with the JDK's standard message parsing provided by
* {@link java.text.MessageFormat}.
*
* This MessageSource caches both the accessed ResourceBundle instances and
* the generated MessageFormats for each message. It also implements rendering of
* no-arg messages without MessageFormat, as supported by the AbstractMessageSource
* base class. The caching provided by this MessageSource is significantly faster
* than the built-in caching of the {@code java.util.ResourceBundle} class.
*
*
The basenames follow {@link java.util.ResourceBundle} conventions: essentially,
* a fully-qualified classpath location. If it doesn't contain a package qualifier
* (such as {@code org.mypackage}), it will be resolved from the classpath root.
* Note that the JDK's standard ResourceBundle treats dots as package separators:
* This means that "test.theme" is effectively equivalent to "test/theme".
*
* @author Rod Johnson
* @author Juergen Hoeller
* @see #setBasenames
* @see ReloadableResourceBundleMessageSource
* @see java.util.ResourceBundle
* @see java.text.MessageFormat
*/
public class ResourceBundleMessageSource extends AbstractMessageSource implements BeanClassLoaderAware {
private String[] basenames = new String[0];
private String defaultEncoding = "ISO-8859-1";
private boolean fallbackToSystemLocale = true;
private long cacheMillis = -1;
private ClassLoader bundleClassLoader;
private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();
/**
* Cache to hold loaded ResourceBundles.
* This Map is keyed with the bundle basename, which holds a Map that is
* keyed with the Locale and in turn holds the ResourceBundle instances.
* This allows for very efficient hash lookups, significantly faster
* than the ResourceBundle class's own cache.
*/
private final Map> cachedResourceBundles =
new HashMap>();
/**
* Cache to hold already generated MessageFormats.
* This Map is keyed with the ResourceBundle, which holds a Map that is
* keyed with the message code, which in turn holds a Map that is keyed
* with the Locale and holds the MessageFormat values. This allows for
* very efficient hash lookups without concatenated keys.
* @see #getMessageFormat
*/
private final Map>> cachedBundleMessageFormats =
new HashMap>>();
/**
* Set a single basename, following {@link java.util.ResourceBundle} conventions:
* essentially, a fully-qualified classpath location. If it doesn't contain a
* package qualifier (such as {@code org.mypackage}), it will be resolved
* from the classpath root.
* Messages will normally be held in the "/lib" or "/classes" directory of
* a web application's WAR structure. They can also be held in jar files on
* the class path.
*
Note that ResourceBundle names are effectively classpath locations: As a
* consequence, the JDK's standard ResourceBundle treats dots as package separators.
* This means that "test.theme" is effectively equivalent to "test/theme",
* just like it is for programmatic {@code java.util.ResourceBundle} usage.
* @see #setBasenames
* @see java.util.ResourceBundle#getBundle(String)
*/
public void setBasename(String basename) {
setBasenames(basename);
}
/**
* Set an array of basenames, each following {@link java.util.ResourceBundle}
* conventions: essentially, a fully-qualified classpath location. If it
* doesn't contain a package qualifier (such as {@code org.mypackage}),
* it will be resolved from the classpath root.
*
The associated resource bundles will be checked sequentially
* when resolving a message code. Note that message definitions in a
* previous resource bundle will override ones in a later bundle,
* due to the sequential lookup.
*
Note that ResourceBundle names are effectively classpath locations: As a
* consequence, the JDK's standard ResourceBundle treats dots as package separators.
* This means that "test.theme" is effectively equivalent to "test/theme",
* just like it is for programmatic {@code java.util.ResourceBundle} usage.
* @see #setBasename
* @see java.util.ResourceBundle#getBundle(String)
*/
public void setBasenames(String... basenames) {
if (basenames != null) {
this.basenames = new String[basenames.length];
for (int i = 0; i < basenames.length; i++) {
String basename = basenames[i];
Assert.hasText(basename, "Basename must not be empty");
this.basenames[i] = basename.trim();
}
}
else {
this.basenames = new String[0];
}
}
/**
* Set the default charset to use for parsing resource bundle files.
*
Default is the {@code java.util.ResourceBundle} default encoding:
* ISO-8859-1.
* @since 3.1.3
*/
public void setDefaultEncoding(String defaultEncoding) {
this.defaultEncoding = defaultEncoding;
}
/**
* Set whether to fall back to the system Locale if no files for a specific
* Locale have been found. Default is "true"; if this is turned off, the only
* fallback will be the default file (e.g. "messages.properties" for
* basename "messages").
*
Falling back to the system Locale is the default behavior of
* {@code java.util.ResourceBundle}. However, this is often not desirable
* in an application server environment, where the system Locale is not relevant
* to the application at all: Set this flag to "false" in such a scenario.
* @since 3.1.3
*/
public void setFallbackToSystemLocale(boolean fallbackToSystemLocale) {
this.fallbackToSystemLocale = fallbackToSystemLocale;
}
/**
* Set the number of seconds to cache loaded resource bundle files.
*
* - Default is "-1", indicating to cache forever.
*
- A positive number will expire resource bundles after the given
* number of seconds. This is essentially the interval between refresh checks.
* Note that a refresh attempt will first check the last-modified timestamp
* of the file before actually reloading it; so if files don't change, this
* interval can be set rather low, as refresh attempts will not actually reload.
*
- A value of "0" will check the last-modified timestamp of the file on
* every message access. Do not use this in a production environment!
*
- Note that depending on your ClassLoader, expiration might not work reliably
* since the ClassLoader may hold on to a cached version of the bundle file.
* Consider {@link ReloadableResourceBundleMessageSource} in combination
* with resource bundle files in a non-classpath location.
*
* @since 3.1.3
*/
public void setCacheSeconds(int cacheSeconds) {
this.cacheMillis = (cacheSeconds * 1000);
}
/**
* Set the ClassLoader to load resource bundles with.
* Default is the containing BeanFactory's
* {@link org.springframework.beans.factory.BeanClassLoaderAware bean ClassLoader},
* or the default ClassLoader determined by
* {@link org.springframework.util.ClassUtils#getDefaultClassLoader()}
* if not running within a BeanFactory.
*/
public void setBundleClassLoader(ClassLoader classLoader) {
this.bundleClassLoader = classLoader;
}
/**
* Return the ClassLoader to load resource bundles with.
*
Default is the containing BeanFactory's bean ClassLoader.
* @see #setBundleClassLoader
*/
protected ClassLoader getBundleClassLoader() {
return (this.bundleClassLoader != null ? this.bundleClassLoader : this.beanClassLoader);
}
@Override
public void setBeanClassLoader(ClassLoader classLoader) {
this.beanClassLoader = (classLoader != null ? classLoader : ClassUtils.getDefaultClassLoader());
}
/**
* Resolves the given message code as key in the registered resource bundles,
* returning the value found in the bundle as-is (without MessageFormat parsing).
*/
@Override
protected String resolveCodeWithoutArguments(String code, Locale locale) {
String result = null;
for (int i = 0; result == null && i < this.basenames.length; i++) {
ResourceBundle bundle = getResourceBundle(this.basenames[i], locale);
if (bundle != null) {
result = getStringOrNull(bundle, code);
}
}
return result;
}
/**
* Resolves the given message code as key in the registered resource bundles,
* using a cached MessageFormat instance per message code.
*/
@Override
protected MessageFormat resolveCode(String code, Locale locale) {
MessageFormat messageFormat = null;
for (int i = 0; messageFormat == null && i < this.basenames.length; i++) {
ResourceBundle bundle = getResourceBundle(this.basenames[i], locale);
if (bundle != null) {
messageFormat = getMessageFormat(bundle, code, locale);
}
}
return messageFormat;
}
/**
* Return a ResourceBundle for the given basename and code,
* fetching already generated MessageFormats from the cache.
* @param basename the basename of the ResourceBundle
* @param locale the Locale to find the ResourceBundle for
* @return the resulting ResourceBundle, or {@code null} if none
* found for the given basename and Locale
*/
protected ResourceBundle getResourceBundle(String basename, Locale locale) {
if (this.cacheMillis >= 0) {
// Fresh ResourceBundle.getBundle call in order to let ResourceBundle
// do its native caching, at the expense of more extensive lookup steps.
return doGetBundle(basename, locale);
}
else {
// Cache forever: prefer locale cache over repeated getBundle calls.
synchronized (this.cachedResourceBundles) {
Map localeMap = this.cachedResourceBundles.get(basename);
if (localeMap != null) {
ResourceBundle bundle = localeMap.get(locale);
if (bundle != null) {
return bundle;
}
}
try {
ResourceBundle bundle = doGetBundle(basename, locale);
if (localeMap == null) {
localeMap = new HashMap();
this.cachedResourceBundles.put(basename, localeMap);
}
localeMap.put(locale, bundle);
return bundle;
}
catch (MissingResourceException ex) {
if (logger.isWarnEnabled()) {
logger.warn("ResourceBundle [" + basename + "] not found for MessageSource: " + ex.getMessage());
}
// Assume bundle not found
// -> do NOT throw the exception to allow for checking parent message source.
return null;
}
}
}
}
/**
* Obtain the resource bundle for the given basename and Locale.
* @param basename the basename to look for
* @param locale the Locale to look for
* @return the corresponding ResourceBundle
* @throws MissingResourceException if no matching bundle could be found
* @see java.util.ResourceBundle#getBundle(String, Locale, ClassLoader)
* @see #getBundleClassLoader()
*/
protected ResourceBundle doGetBundle(String basename, Locale locale) throws MissingResourceException {
return ResourceBundle.getBundle(basename, locale, getBundleClassLoader(), new MessageSourceControl());
}
/**
* Load a property-based resource bundle from the given reader.
* The default implementation returns a {@link PropertyResourceBundle}.
* @param reader the reader for the target resource
* @return the fully loaded bundle
* @throws IOException in case of I/O failure
* @since 4.2
* @see PropertyResourceBundle#PropertyResourceBundle(Reader)
*/
protected ResourceBundle loadBundle(Reader reader) throws IOException {
return new PropertyResourceBundle(reader);
}
/**
* Return a MessageFormat for the given bundle and code,
* fetching already generated MessageFormats from the cache.
* @param bundle the ResourceBundle to work on
* @param code the message code to retrieve
* @param locale the Locale to use to build the MessageFormat
* @return the resulting MessageFormat, or {@code null} if no message
* defined for the given code
* @throws MissingResourceException if thrown by the ResourceBundle
*/
protected MessageFormat getMessageFormat(ResourceBundle bundle, String code, Locale locale)
throws MissingResourceException {
synchronized (this.cachedBundleMessageFormats) {
Map> codeMap = this.cachedBundleMessageFormats.get(bundle);
Map localeMap = null;
if (codeMap != null) {
localeMap = codeMap.get(code);
if (localeMap != null) {
MessageFormat result = localeMap.get(locale);
if (result != null) {
return result;
}
}
}
String msg = getStringOrNull(bundle, code);
if (msg != null) {
if (codeMap == null) {
codeMap = new HashMap>();
this.cachedBundleMessageFormats.put(bundle, codeMap);
}
if (localeMap == null) {
localeMap = new HashMap();
codeMap.put(code, localeMap);
}
MessageFormat result = createMessageFormat(msg, locale);
localeMap.put(locale, result);
return result;
}
return null;
}
}
/**
* Efficiently retrieve the String value for the specified key,
* or return {@code null} if not found.
* As of 4.2, the default implementation checks {@code containsKey}
* before it attempts to call {@code getString} (which would require
* catching {@code MissingResourceException} for key not found).
*
Can be overridden in subclasses.
* @param bundle the ResourceBundle to perform the lookup in
* @param key the key to look up
* @return the associated value, or {@code null} if none
* @since 4.2
* @see ResourceBundle#getString(String)
* @see ResourceBundle#containsKey(String)
*/
protected String getStringOrNull(ResourceBundle bundle, String key) {
if (bundle.containsKey(key)) {
try {
return bundle.getString(key);
}
catch (MissingResourceException ex){
// Assume key not found for some other reason
// -> do NOT throw the exception to allow for checking parent message source.
}
}
return null;
}
/**
* Show the configuration of this MessageSource.
*/
@Override
public String toString() {
return getClass().getName() + ": basenames=[" + StringUtils.arrayToCommaDelimitedString(this.basenames) + "]";
}
/**
* Custom implementation of Java 6's {@code ResourceBundle.Control},
* adding support for custom file encodings, deactivating the fallback to the
* system locale and activating ResourceBundle's native cache, if desired.
*/
private class MessageSourceControl extends ResourceBundle.Control {
@Override
public ResourceBundle newBundle(String baseName, Locale locale, String format, ClassLoader loader, boolean reload)
throws IllegalAccessException, InstantiationException, IOException {
// Special handling of default encoding
if (format.equals("java.properties")) {
String bundleName = toBundleName(baseName, locale);
final String resourceName = toResourceName(bundleName, "properties");
final ClassLoader classLoader = loader;
final boolean reloadFlag = reload;
InputStream stream;
try {
stream = AccessController.doPrivileged(
new PrivilegedExceptionAction() {
@Override
public InputStream run() throws IOException {
InputStream is = null;
if (reloadFlag) {
URL url = classLoader.getResource(resourceName);
if (url != null) {
URLConnection connection = url.openConnection();
if (connection != null) {
connection.setUseCaches(false);
is = connection.getInputStream();
}
}
}
else {
is = classLoader.getResourceAsStream(resourceName);
}
return is;
}
});
}
catch (PrivilegedActionException ex) {
throw (IOException) ex.getException();
}
if (stream != null) {
try {
return loadBundle(new InputStreamReader(stream, defaultEncoding));
}
finally {
stream.close();
}
}
else {
return null;
}
}
else {
// Delegate handling of "java.class" format to standard Control
return super.newBundle(baseName, locale, format, loader, reload);
}
}
@Override
public Locale getFallbackLocale(String baseName, Locale locale) {
return (fallbackToSystemLocale ? super.getFallbackLocale(baseName, locale) : null);
}
@Override
public long getTimeToLive(String baseName, Locale locale) {
return (cacheMillis >= 0 ? cacheMillis : super.getTimeToLive(baseName, locale));
}
@Override
public boolean needsReload(String baseName, Locale locale, String format, ClassLoader loader, ResourceBundle bundle, long loadTime) {
if (super.needsReload(baseName, locale, format, loader, bundle, loadTime)) {
cachedBundleMessageFormats.remove(bundle);
return true;
}
else {
return false;
}
}
}
}