Mercurial > hg > LightPIT / changeset

     1.1 --- a/src/main/java/de/uapcore/lightpit/AbstractLightPITServlet.java	Mon May 18 21:05:57 2020 +0200
     1.2 +++ b/src/main/java/de/uapcore/lightpit/AbstractLightPITServlet.java	Mon May 18 21:06:38 2020 +0200
     1.3 @@ -45,6 +45,7 @@
     1.4  import java.sql.Connection;
     1.5  import java.sql.SQLException;
     1.6  import java.util.*;
     1.7 +import java.util.function.Function;
     1.8  
     1.9  /**
    1.10   * A special implementation of a HTTPServlet which is focused on implementing
    1.11 @@ -61,6 +62,25 @@
    1.12       */
    1.13      private LightPITModule.ELProxy moduleInfo = null;
    1.14  
    1.15 +    @FunctionalInterface
    1.16 +    protected interface SQLFindFunction<K, T> {
    1.17 +        T apply(K key) throws SQLException;
    1.18 +
    1.19 +        default <V> SQLFindFunction<V, T> compose(Function<? super V, ? extends K> before) throws SQLException {
    1.20 +            Objects.requireNonNull(before);
    1.21 +            return (v) -> this.apply(before.apply(v));
    1.22 +        }
    1.23 +
    1.24 +        default <V> SQLFindFunction<K, V> andThen(Function<? super T, ? extends V> after) throws SQLException {
    1.25 +            Objects.requireNonNull(after);
    1.26 +            return (t) -> after.apply(this.apply(t));
    1.27 +        }
    1.28 +
    1.29 +        static <K> Function<K, K> identity() {
    1.30 +            return (t) -> t;
    1.31 +        }
    1.32 +    }
    1.33 +
    1.34      /**
    1.35       * Invocation mapping gathered from the {@link RequestMapping} annotations.
    1.36       * <p>
    1.37 @@ -224,7 +244,7 @@
    1.38       * @param fragmentName the name of the fragment
    1.39       * @see Constants#DYN_FRAGMENT_PATH_PREFIX
    1.40       */
    1.41 -    public void setDynamicFragment(HttpServletRequest req, String fragmentName) {
    1.42 +    protected void setDynamicFragment(HttpServletRequest req, String fragmentName) {
    1.43          req.setAttribute(Constants.REQ_ATTR_FRAGMENT, Functions.dynFragmentPath(fragmentName));
    1.44      }
    1.45  
    1.46 @@ -233,7 +253,7 @@
    1.47       * @param location the location where to redirect
    1.48       * @see Constants#REQ_ATTR_REDIRECT_LOCATION
    1.49       */
    1.50 -    public void setRedirectLocation(HttpServletRequest req, String location) {
    1.51 +    protected void setRedirectLocation(HttpServletRequest req, String location) {
    1.52          if (location.startsWith("./")) {
    1.53              location = location.replaceFirst("\\./", Functions.baseHref(req));
    1.54          }
    1.55 @@ -267,7 +287,7 @@
    1.56       * @param <T> the expected type
    1.57       * @return the parameter value or an empty optional, if no parameter with the specified name was found
    1.58       */
    1.59 -    public<T> Optional<T> getParameter(HttpServletRequest req, Class<T> clazz, String name) {
    1.60 +    protected<T> Optional<T> getParameter(HttpServletRequest req, Class<T> clazz, String name) {
    1.61          final String paramValue = req.getParameter(name);
    1.62          if (paramValue == null) return Optional.empty();
    1.63          if (clazz.equals(String.class)) return Optional.of((T)paramValue);
    1.64 @@ -280,6 +300,27 @@
    1.65  
    1.66      }
    1.67  
    1.68 +    /**
    1.69 +     * Tries to look up an entity with a key obtained from a request parameter.
    1.70 +     *
    1.71 +     * @param req the servlet request object
    1.72 +     * @param clazz the class representing the type of the request parameter
    1.73 +     * @param name the name of the request parameter
    1.74 +     * @param find the find function (typically a DAO function)
    1.75 +     * @param <T> the type of the request parameter
    1.76 +     * @param <R> the type of the looked up entity
    1.77 +     * @return the retrieved entity or an empty optional if there is no such entity or the request parameter was missing
    1.78 +     * @throws SQLException if the find function throws an exception
    1.79 +     */
    1.80 +    protected<T,R> Optional<R> findByParameter(HttpServletRequest req, Class<T> clazz, String name, SQLFindFunction<? super T, ? extends R> find) throws SQLException {
    1.81 +        final var param = getParameter(req, clazz, name);
    1.82 +        if (param.isPresent()) {
    1.83 +            return Optional.ofNullable(find.apply(param.get()));
    1.84 +        } else {
    1.85 +            return Optional.empty();
    1.86 +        }
    1.87 +    }
    1.88 +
    1.89      private void forwardToFullView(HttpServletRequest req, HttpServletResponse resp)
    1.90              throws IOException, ServletException {
    1.91