[jboss-jira] [JBoss JIRA] (LOGTOOL-132) Support low-metaspace bundles/classes

Support low-metaspace bundles/classes ------------------------------------- Key: LOGTOOL-132 URL: https://issues.jboss.org/browse/LOGTOOL-132 Project: Log Tool Issue Type: Enhancement Reporter: David Lloyd Priority: Critical Metaspace is at a premium in the application server environment, and the number one consumer is presently generated log classes. Introduce a leaner variation on generated classes with the following requirements: * The generated class must be {{final}} * The generated class must contain no message strings * The generated class must accept both a {{Logger}} and a {{Locale}}, and load its resources from a file based on that information * The usage of Java 8's locale lookup functionality should be considered, to support language tags etc.; a helper utility could be introduced into {{jboss-logging}} for this Here are some implementation ideas: * Option 1: The resource files contain only messages, one per line, loaded directly into a {{String[]}} instance field in the implementation class; each logging method uses a hard-coded array index to access its message ** A key advantage is that the implementation class is very small, and consumes very little metaspace; also, it is fast, requiring only an array lookup to acquire the string ** A disadvantage is, any change to the message set invalidates all the locale files, which must then be regenerated ** Also, each locale file must contain all messages, unless a fallback mechanism is used (e.g. an empty line signifies that the string should come from the parent locale) * Option 2: The resource files contain key-value pairs, with the key being equal to the method name ** Advantage: the file is not invalidated if a key is added, and sub-locales can inherit more easily from parent locales ** Disadvantage: the added overhead of mapping lines to methods (for example, using a switch statement to map method names to fixed indexes, or loading the messages into a hash table e.g. {{HashMap}}) will fill metaspace or impact performance, or both