Database Resource Bundle Message Source Spring Boot Starter

This is a Spring Boot autoconfiguration and starter artifact for Database Resource Bundle which is an database backed implementation of java.util.ResourceBundle.

Quick Start

1. Add dependency via Jitpack
2. Create a JPA entity class which implements BundleEntity
3. Populate the table which corresponds to the entity class you've declared in step 2 and you're ready to roll.

See usage demo project for code samples.

Usage

This starter instantiates a bean of JpaBundleContentLoaderStrategy if there is no bean of type BundleContentLoaderStrategy is present in context.

Using JpaBundleContentLoaderStrategy (Default with this starter)

When using JpaBundleContentLoaderStrategy you need to have an entity which implements BundleEntity.

By default, this starter will scan for an entity which implements BundleEntity. However, this takes time (~1s) and decrease your startup time (but has no effect on runtime performance). If startup time is important for you then you can instantiate a bean of JpaBundleContentLoaderStrategy where you explicitly declare your entity class. So that there won't be any scanning.

Instantiating JpaBundleContentLoaderStrategy manually

@Bean
BundleContentLoaderStrategy bundleContentLoaderStrategy(EntityManager entityManager) {
  return new JpaBundleContentLoaderStrategy<>(entityManager, MyBundleEntity.class);
}

Using DefaultBundleContentLoaderStrategy

DefaultBundleContentLoaderStrategy uses a prepared statement to load resource content.

By default it assumes you have a table in your database which is created via database-resource-bundle.jar/create.sql. Hence uses following queries:

DEFAULT_LOAD_QUERY = "SELECT DISTINCT b.key, b.value FROM " + DEFAULT_TABLE_NAME + " b WHERE name = ? AND language = ? AND country = ? AND variant = ? ;"
DEFAULT_NEEDS_RELOAD_QUERY = "SELECT MAX(last_modified) FROM " + DEFAULT_TABLE_NAME + " b WHERE name = ? ;";

DEFAULT_TABLE_NAME is Bundle and coming from BundleContentLoaderStrategy.DEFAULT_TABLE_NAME.

Using a different Table name or completely different Table structure

You can override those queries by using DefaultBundleContentLoaderStrategy's 3-parameter constructor. When you do this, you can use any database table structure or name as you like as long as you conform to expected return values of the queries.

Expected return values of the load query is a key-value string pair.

Expected return values of the needs reload query is a long value which represents the epoch milliseconds of latest change on the table.

Defaults

This starter;

1. Instantiates a bean of JpaBundleContentLoaderStrategy if there is no bean of type BundleContentLoaderStrategy is present in context. If there is a bean of type BundleContentLoaderStrategy, for example DefaultBundleContentLoaderStrategy or your custom implementation, then JpaBundleContentLoaderStrategy is not instantiated (hence there won't be a class scanning for an entity class implementing BundleEntity) and the existing bean is used.
2. Configures a DatabaseResourceBundleMessageSource which uses the BundleContentLoaderStrategy implementation.
3. DatabaseResourceBundleMessageSource is a MessageSource so you don't need to configure anything else, just use Spring's messages.properties support as before but this time instead of a properties file it's backed by a database table.

Configuration

You can use Spring Boot's message source properties to change DatabaseResourceBundleMessageSource's behavior:

spring.messages.always-use-message-format=false # Whether to always apply the MessageFormat rules, parsing even messages without arguments.
spring.messages.basename=messages # Comma-separated list of basenames (essentially a fully-qualified classpath location), each following the ResourceBundle convention with relaxed support for slash based locations.
spring.messages.cache-duration= # Loaded resource bundle files cache duration. When not set, bundles are cached forever. If a duration suffix is not specified, seconds will be used.
spring.messages.encoding=UTF-8 # Message bundles encoding.
spring.messages.fallback-to-system-locale=true # Whether to fall back to the system Locale if no files for a specific Locale have been found.
spring.messages.use-code-as-default-message=false # Whether to use the message code as the default message instead of throwing a "NoSuchMessageException". Recommended during development only.

See also MessageSourceProperties;

LICENSE

© Copyright 2018 Kod Gemisi Ltd.

Mozilla Public License 2.0 (MPL-2.0)

https://tldrlegal.com/license/mozilla-public-license-2.0-(mpl-2)

MPL is a copyleft license that is easy to comply with. You must make the source code for any of your changes available under MPL, but you can combine the MPL software with proprietary code, as long as you keep the MPL code in separate files. Version 2.0 is, by default, compatible with LGPL and GPL version 2 or greater. You can distribute binaries under a proprietary license, as long as you make the source available under MPL.

See Full License Here