public DozerBeanMapperBuilder withELEngine(ELEngine elEngine) {
        this.elEngine = elEngine;
        return this;
    }
Registers a {@link ELEngine} for the mapper.
Which can be used to resolve expressions within the defined mappings.
<p>
By default, {@link NoopELEngine} is registered,
unless {@link com.sun.el.ExpressionFactoryImpl} is detected on classpath, then {@link DefaultELEngine}

@param elEngine elEngine to use
@return modified builder to be further configured.
core/src/main/java/com/github/dozermapper/core/DozerBeanMapperBuilder.java