[LOG4J2-1507] Allow Builders to be completely generic

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.7
• Component/s: Configurators
• Assignee: Gary D. Gregory
• Reporter: Gary D. Gregory
• Created: 10/Aug/16 00:34
• Updated: 10/Aug/16 10:59
• Resolved: 10/Aug/16 00:36

Description

Allow Builders to be completely generic. This is not just supporting Builder<T>, which works in 2.6.2, but to allow declarations like Builder<B extends Builder<B>> combined with setters that return B.

    public static class Builder<B extends Builder<B>> implements org.apache.logging.log4j.core.util.Builder<ValidatingPluginWithGenericBuilder> {

        @PluginBuilderAttribute
        @Required(message = "The name given by the builder is null")
        private String name;

        public B withName(final String name) {
            this.name = name;
            return asBuilder();
        }

        @SuppressWarnings("unchecked")
        private B asBuilder() {
            return (B) this;
        }

        @Override
        public ValidatingPluginWithGenericBuilder build() {
            return new ValidatingPluginWithGenericBuilder(name);
        }
    }

(I have a patch for this)

(The next step (and ticket) will be to allow to use a Builder that extends another Builder.)

Issue Links

• is required by: LOG4J2-1508 Allow a Builder to subclass another Builder