org.springframework.integration.expression

Class ReloadableResourceBundleExpressionSource

java.lang.Object

org.springframework.integration.expression.ReloadableResourceBundleExpressionSource

All Implemented Interfaces:

Aware, ResourceLoaderAware, ExpressionSource

public class ReloadableResourceBundleExpressionSource
extends Object
implements ExpressionSource, ResourceLoaderAware

ExpressionSource implementation that accesses resource bundles using specified basenames. This class uses Properties instances as its custom data structure for expressions, loading them via a PropertiesPersister strategy: The default strategy is capable of loading properties files with a specific character encoding, if desired.

Since:

2.0

Author:

Juergen Hoeller, Mark Fisher, Gary Russell, Artem Bilan

See Also:

setCacheSeconds(int), setBasenames(java.lang.String[]), setDefaultEncoding(java.lang.String), setFileEncodings(java.util.Properties), setPropertiesPersister(org.springframework.util.PropertiesPersister), setResourceLoader(org.springframework.core.io.ResourceLoader), DefaultPropertiesPersister, DefaultResourceLoader, ResourceBundle

Constructor Summary

Constructors

Constructor and Description
ReloadableResourceBundleExpressionSource()

Method Summary

Modifier and Type	Method and Description
void	clearCache() Clear the resource bundle cache.
Expression	getExpression(String key, Locale locale) Resolves the given key in the retrieved bundle files to an Expression.
void	setBasename(String basename) Set a single basename, following the basic ResourceBundle convention of not specifying file extension or language codes, but referring to a Spring resource location: e.g.
void	setBasenames(String[] basenames) Set an array of basenames, each following the basic ResourceBundle convention of not specifying file extension or language codes, but referring to a Spring resource location: e.g.
void	setCacheSeconds(int cacheSeconds) Set the number of seconds to cache loaded properties files.
void	setDefaultEncoding(String defaultEncoding) Set the default charset to use for parsing properties files.
void	setFallbackToSystemLocale(boolean fallbackToSystemLocale) Set whether to fall back to the system Locale if no files for a specific Locale have been found.
void	setFileEncodings(Properties fileEncodings) Set per-file charsets to use for parsing properties files.
void	setPropertiesPersister(PropertiesPersister propertiesPersister) Set the PropertiesPersister to use for parsing properties files.
void	setResourceLoader(ResourceLoader resourceLoader) Set the ResourceLoader to use for loading bundle properties files.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ReloadableResourceBundleExpressionSource

public ReloadableResourceBundleExpressionSource()

Method Detail

setBasename

public void setBasename(String basename)

Set a single basename, following the basic ResourceBundle convention of not specifying file extension or language codes, but referring to a Spring resource location: e.g. "META-INF/expressions" for "META-INF/expressions.properties", "META-INF/expressions_en.properties", etc.

XML properties files are also supported: .g. "META-INF/expressions" will find and load "META-INF/expressions.xml", "META-INF/expressions_en.xml", etc as well.

Parameters:

basename - the single basename

See Also:

setBasenames(java.lang.String[]), ResourceEditor, ResourceBundle

setBasenames

public void setBasenames(@Nullable
                         String[] basenames)

Set an array of basenames, each following the basic ResourceBundle convention of not specifying file extension or language codes, but referring to a Spring resource location: e.g. "META-INF/expressions" for "META-INF/expressions.properties", "META-INF/expressions_en.properties", etc.

XML properties files are also supported: .g. "META-INF/expressions" will find and load "META-INF/expressions.xml", "META-INF/expressions_en.xml", etc as well.

The associated resource bundles will be checked sequentially when resolving an expression key. Note that expression definitions in a previous resource bundle will override ones in a later bundle, due to the sequential lookup.

Parameters:

basenames - an array of basenames

See Also:

setBasename(java.lang.String), ResourceBundle

setDefaultEncoding

public void setDefaultEncoding(String defaultEncoding)

Set the default charset to use for parsing properties files. Used if no file-specific charset is specified for a file.

Default is none, using the java.util.Properties default encoding.

Only applies to classic properties files, not to XML files.

Parameters:

defaultEncoding - the default charset

See Also:

setFileEncodings(java.util.Properties), PropertiesPersister.load(java.util.Properties, java.io.InputStream)

setFileEncodings

public void setFileEncodings(Properties fileEncodings)

Set per-file charsets to use for parsing properties files.

Only applies to classic properties files, not to XML files.

Parameters:

fileEncodings - Properties with filenames as keys and charset names as values. Filenames have to match the basename syntax, with optional locale-specific appendices: e.g. "META-INF/expressions" or "META-INF/expressions_en".

See Also:

setBasenames(java.lang.String[]), PropertiesPersister.load(java.util.Properties, java.io.InputStream)

setFallbackToSystemLocale

public void setFallbackToSystemLocale(boolean fallbackToSystemLocale)

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. "expressions.properties" for basename "expressions").

Falling back to the system Locale is the default behavior of 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.

Parameters:

fallbackToSystemLocale - true to fall back.

setCacheSeconds

public void setCacheSeconds(int cacheSeconds)

Set the number of seconds to cache loaded properties files.

• Default is "-1", indicating to cache forever (just like java.util.ResourceBundle).
• 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.
• A value of "0" will check the last-modified timestamp of the file on every expression access. Do not use this in a production environment!

Parameters:

cacheSeconds - The cache seconds.

setPropertiesPersister

public void setPropertiesPersister(@Nullable
                                   PropertiesPersister propertiesPersister)

Set the PropertiesPersister to use for parsing properties files.

The default is a DefaultPropertiesPersister.

Parameters:

propertiesPersister - The properties persister.

See Also:

DefaultPropertiesPersister

setResourceLoader

public void setResourceLoader(@Nullable
                              ResourceLoader resourceLoader)

Set the ResourceLoader to use for loading bundle properties files.

The default is a DefaultResourceLoader. Will get overridden by the ApplicationContext if running in a context, as it implements the ResourceLoaderAware interface. Can be manually overridden when running outside of an ApplicationContext.

Specified by:

setResourceLoader in interface ResourceLoaderAware

See Also:

DefaultResourceLoader, ResourceLoaderAware

getExpression

public Expression getExpression(String key,
                                Locale locale)

Resolves the given key in the retrieved bundle files to an Expression.

Specified by:

getExpression in interface ExpressionSource

clearCache

public void clearCache()

Clear the resource bundle cache. Subsequent resolve calls will lead to reloading of the properties files.

toString

public String toString()

Overrides:

toString in class Object