protected void setLogoutProcessorIfUndefined(final LogoutProcessor logoutProcessor) {
        if (this.logoutProcessor == null) {
            this.logoutProcessor = logoutProcessor;
        }
    }
<p>setLogoutProcessorIfUndefined.</p>

@param logoutProcessor a {@link LogoutProcessor} object
pac4j-core/src/main/java/org/pac4j/core/client/IndirectClient.java