protected static ExpressionFactory getUserDefinedExpressionFactory(ExternalContext externalContext)
    {
        String expressionFactoryClassName
                = WebConfigParamUtils.getStringInitParameter(externalContext, EXPRESSION_FACTORY);
        if (expressionFactoryClassName != null
                && expressionFactoryClassName.trim().length() > 0)
        {
            if (log.isLoggable(Level.FINE))
            {
                log.fine("Attempting to load the ExpressionFactory implementation "
                        + "you've specified: '" + expressionFactoryClassName + "'.");
            }

            return loadExpressionFactory(expressionFactoryClassName);
        }

        return null;
    }
protected static ExpressionFactory getUserDefinedExpressionFactory ( ExternalContext externalContext ) { String expressionFactoryClassName = WebConfigParamUtils . getStringInitParameter ( externalContext , EXPRESSION_FACTORY ) ; if ( expressionFactoryClassName != null && expressionFactoryClassName . trim ( ) . length ( ) > 0 ) { if ( log . isLoggable ( Level . FINE ) ) { log . fine ( "Attempting to load the ExpressionFactory implementation " + "you've specified: '" + expressionFactoryClassName + "'." ) ; } return loadExpressionFactory ( expressionFactoryClassName ) ; } return null ; }
Try to load user-definied ExpressionFactory. Returns <code>null</code>,
if no custom ExpressionFactory was specified.

@param externalContext the current ExternalContext
@return User-specified ExpressionFactory, or
<code>null</code>, if no no custom implementation was specified