/*
* 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.util.LinkedHashSet;
import java.util.Set;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
/**
* Abstract base class for {@code MessageSource} implementations based on
* resource bundle conventions, such as {@link ResourceBundleMessageSource}
* and {@link ReloadableResourceBundleMessageSource}. Provides common
* configuration methods and corresponding semantic definitions.
*
* @author Juergen Hoeller
* @since 4.3
* @see ResourceBundleMessageSource
* @see ReloadableResourceBundleMessageSource
*/
public abstract class AbstractResourceBasedMessageSource extends AbstractMessageSource {
private final Set<String> basenameSet = new LinkedHashSet<>(4);
private String defaultEncoding;
private boolean fallbackToSystemLocale = true;
private long cacheMillis = -1;
/**
* Set a single basename, following the basic ResourceBundle convention
* of not specifying file extension or language codes. The resource location
* format is up to the specific {@code MessageSource} implementation.
* <p>Regular and XMl properties files are supported: e.g. "messages" will find
* a "messages.properties", "messages_en.properties" etc arrangement as well
* as "messages.xml", "messages_en.xml" etc.
* @param basename the single basename
* @see #setBasenames
* @see org.springframework.core.io.ResourceEditor
* @see java.util.ResourceBundle
*/
public void setBasename(String basename) {
setBasenames(basename);
}
/**
* Set an array of basenames, each following the basic ResourceBundle convention
* of not specifying file extension or language codes. The resource location
* format is up to the specific {@code MessageSource} implementation.
* <p>Regular and XMl properties files are supported: e.g. "messages" will find
* a "messages.properties", "messages_en.properties" etc arrangement as well
* as "messages.xml", "messages_en.xml" etc.
* <p>The associated resource bundles will be checked sequentially when resolving
* a message code. Note that message definitions in a <i>previous</i> resource
* bundle will override ones in a later bundle, due to the sequential lookup.
* <p>Note: In contrast to {@link #addBasenames}, this replaces existing entries
* with the given names and can therefore also be used to reset the configuration.
* @param basenames an array of basenames
* @see #setBasename
* @see java.util.ResourceBundle
*/
public void setBasenames(String... basenames) {
this.basenameSet.clear();
addBasenames(basenames);
}
/**
* Add the specified basenames to the existing basename configuration.
* <p>Note: If a given basename already exists, the position of its entry
* will remain as in the original set. New entries will be added at the
* end of the list, to be searched after existing basenames.
* @since 4.3
* @see #setBasenames
* @see java.util.ResourceBundle
*/
public void addBasenames(String... basenames) {
if (!ObjectUtils.isEmpty(basenames)) {
for (String basename : basenames) {
Assert.hasText(basename, "Basename must not be empty");
this.basenameSet.add(basename.trim());
}
}
}
/**
* Return this {@code MessageSource}'s basename set, containing entries
* in the order of registration.
* <p>Calling code may introspect this set as well as add or remove entries.
* @since 4.3
* @see #addBasenames
*/
public Set<String> getBasenameSet() {
return this.basenameSet;
}
/**
* Set the default charset to use for parsing properties files.
* Used if no file-specific charset is specified for a file.
* <p>Default is none, using the {@code java.util.Properties}
* default encoding: ISO-8859-1.
* <p>Only applies to classic properties files, not to XML files.
* @param defaultEncoding the default charset
*/
public void setDefaultEncoding(String defaultEncoding) {
this.defaultEncoding = defaultEncoding;
}
/**
* Return the default charset to use for parsing properties files, if any.
* @since 4.3
*/
protected String getDefaultEncoding() {
return this.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").
* <p>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.
*/
public void setFallbackToSystemLocale(boolean fallbackToSystemLocale) {
this.fallbackToSystemLocale = fallbackToSystemLocale;
}
/**
* Return whether to fall back to the system Locale if no files for a specific
* Locale have been found.
* @since 4.3
*/
protected boolean isFallbackToSystemLocale() {
return this.fallbackToSystemLocale;
}
/**
* Set the number of seconds to cache loaded properties files.
* <ul>
* <li>Default is "-1", indicating to cache forever (just like
* {@code java.util.ResourceBundle}).
* <li>A positive number will cache loaded properties files for 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.
* <li>A value of "0" will check the last-modified timestamp of the file on
* every message access. <b>Do not use this in a production environment!</b>
* </ul>
* <p><b>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.</b>
* Prefer {@link ReloadableResourceBundleMessageSource} over
* {@link ResourceBundleMessageSource} in such a scenario, in combination with
* a non-classpath location.
*/
public void setCacheSeconds(int cacheSeconds) {
this.cacheMillis = (cacheSeconds * 1000);
}
/**
* Set the number of milliseconds to cache loaded properties files.
* Note that it is common to set seconds instead: {@link #setCacheSeconds}.
* <ul>
* <li>Default is "-1", indicating to cache forever (just like
* {@code java.util.ResourceBundle}).
* <li>A positive number will cache loaded properties files for the given
* number of milliseconds. 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.
* <li>A value of "0" will check the last-modified timestamp of the file on
* every message access. <b>Do not use this in a production environment!</b>
* </ul>
* @since 4.3
* @see #setCacheSeconds
*/
public void setCacheMillis(long cacheMillis) {
this.cacheMillis = cacheMillis;
}
/**
* Return the number of milliseconds to cache loaded properties files.
* @since 4.3
*/
protected long getCacheMillis() {
return this.cacheMillis;
}
}