Issue #1941 – Improvements to Rendering Customiser

dev-misc/scripts/fix-rendering-customisers.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+command grep -l -E --include='*.java' 'implements\s+IRenderingCustomiser<Map<String,\s*Object>>' -R . \
+    | xargs sed -E -i \
+    -e '10a import ua.com.fielden.platform.web.centre.api.resultset.CssRenderingCustomiser;' \
+    -e 's/implements\s+IRenderingCustomiser<Map<String,\s*Object>>/extends CssRenderingCustomiser/g' \
+    -e 's/Optional<Map<String,\s*Object>>\s+getCustomRenderingFor/Map<String, Object> getCustomRenderingFor/g'

platform-web-resources/src/main/java/ua/com/fielden/platform/web/resources/webui/CriteriaResource.java

@@ -760,7 +760,7 @@ private List<Integer> createPrimaryActionIndices(final List<?> entities) {
     }
 
     /**
-     * Calculates rendering hints for {@code entities}.
+     * Calculates rendering hints for {@code entities}. The returned list must be either empty or strictly of the same length as the input list.
      *
      * @param entities
      * @return
@@ -771,7 +771,7 @@ private List<Object> createRenderingHints(final List<?> entities) {
             final IRenderingCustomiser<?> renderer = renderingCustomiser.get();
             final List<Object> renderingHints = new ArrayList<>();
             for (final Object entity : entities) {
-                renderingHints.add(renderer.getCustomRenderingFor((AbstractEntity<?>)entity).get());
+                renderingHints.add(renderer.getCustomRenderingFor((AbstractEntity<?>)entity));
             }
             return renderingHints;
         } else {

platform-web-resources/src/main/java/ua/com/fielden/platform/web/test/server/TestRenderingCustomiser.java

@@ -4,13 +4,12 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Optional;
 
 import ua.com.fielden.platform.entity.AbstractEntity;
 import ua.com.fielden.platform.sample.domain.TgPersistentStatus;
-import ua.com.fielden.platform.web.centre.api.resultset.IRenderingCustomiser;
+import ua.com.fielden.platform.web.centre.api.resultset.CssRenderingCustomiser;
 
-public class TestRenderingCustomiser implements IRenderingCustomiser<Map<String, Object>> {
+public class TestRenderingCustomiser extends CssRenderingCustomiser {
     private final Map<String, String> statusColouringScheme = new HashMap<String, String>() {
         {
             put("dR", "yellow");
@@ -33,7 +32,7 @@ public class TestRenderingCustomiser implements IRenderingCustomiser<Map<String,
     };
 
     @Override
-    public Optional<Map<String, Object>> getCustomRenderingFor(final AbstractEntity<?> entity) {
+    public Map<String, Object> getCustomRenderingFor(final AbstractEntity<?> entity) {
         final Map<String, Object> res = new HashMap<>();
         for (final String propName : properties) {
             final Map<String, Map<String, String>> propStyle = new HashMap<>();
@@ -54,23 +53,23 @@ public Optional<Map<String, Object>> getCustomRenderingFor(final AbstractEntity<
 
         final TgPersistentStatus currentStatus = entity.get("status");
         for (final Map.Entry<String, String> entry : statusColouringScheme.entrySet()) {
-            
+
             final Map<String, Map<String, String>> propStyle = new HashMap<>();
             res.put(entry.getKey(), propStyle);
-            
+
             final Map<String, String> backgroundStyles = new HashMap<>();
             final Map<String, String> valueStyles = new HashMap<>();
             propStyle.put("backgroundStyles", backgroundStyles);
             propStyle.put("valueStyles", valueStyles);
-            
+
             // TODO uncomment to hide the "X" value in calculated properties, which is really needed only for data export
             //valueStyles.put("visibility", "hidden");
             if (currentStatus != null && entry.getKey().equalsIgnoreCase(currentStatus.getKey())) {
                backgroundStyles.put("background-color", entry.getValue());
             }
-
-
         }
-        return Optional.of(res);
-    };
+
+        return res;
+    }
+
 }

platform-web-ui/src/main/java/ua/com/fielden/platform/web/centre/api/resultset/CssRenderingCustomiser.java

@@ -0,0 +1,24 @@
+package ua.com.fielden.platform.web.centre.api.resultset;
+
+import java.util.Collections;
+import java.util.Map;
+
+/**
+ * An abstract base class for implementation of CSS rendering customisers, used by the Entity Centre DSL.
+ *
+ * @see IRenderingCustomiser
+ * @author TG Team
+ */
+public abstract class CssRenderingCustomiser implements IRenderingCustomiser<Map<String, Object>> {
+
+    protected static final String BACKGROUND_STYLES = "backgroundStyles";
+    protected static final String VALUE_STYLES = "valueStyles";
+
+    private static final Map<String, Object> EMPTY_HINTS = Collections.emptyMap();
+
+    @Override
+    public final Map<String, Object> empty() {
+        return EMPTY_HINTS;
+    }
+
+}

platform-web-ui/src/main/java/ua/com/fielden/platform/web/centre/api/resultset/IRenderingCustomiser.java

@@ -1,7 +1,5 @@
 package ua.com.fielden.platform.web.centre.api.resultset;
 
-import java.util.Optional;
-
 import ua.com.fielden.platform.entity.AbstractEntity;
 
 /**
@@ -13,23 +11,29 @@
  * <p>
  * This contract should be view as a function that returns rendering hints for a single passed as an argument entity.
  * <p>
- * This type is not parameterized by <code>T extends AbstractEntity<?></code> specifically to reflect the fact that the entities, which are handled by entity centres are derived from a concrete entity type, but are not polymorphic with it. 
+ * This type is not parameterized by <code>T extends AbstractEntity<?></code> specifically to reflect the fact that the entities, which are handled by entity centres are derived from a concrete entity type, but are not polymorphic with it.
  *
  * @author TG Team
  *
- * @param <R>
+ * @param <R> the type of the structure of rendering hints
  */
 public interface IRenderingCustomiser<R> {
 
     /**
      * Accepts an entity instance and computes rendering hints for its representation, and representation of its properties.
      * <p>
      * There could be a situation where an entity instance does not require customisation of its rendering.
-     * In such cases an empty {@link Optional} instance should be returned, which is the default implementation of this contract.
+     * In such cases the result of {@link #empty()} should be returned, which is the default implementation of this contract.
      *
      * @param entity
      */
-    default Optional<R> getCustomRenderingFor(final AbstractEntity<?> entity) {
-        return Optional.empty();
+    default R getCustomRenderingFor(final AbstractEntity<?> entity) {
+        return empty();
     }
+
+    /**
+     * Returns an empty structure of rendering hints.
+     */
+    R empty();
+
 }