ViewColumn/ViewLayout usability improvements

#717

src/main/java/de/metas/ui/web/view/descriptor/ViewLayout.java

@@ -599,6 +599,15 @@ public <T extends IViewRow> Builder addElementsFromViewRowClass(final Class<T> v
 			return this;
 		}
 
+		public <T extends IViewRow> Builder addElementsFromViewRowClassAndFieldNames(final Class<T> viewRowClass, final String... fieldNames)
+		{
+			final List<DocumentLayoutElementDescriptor.Builder> elements = ViewColumnHelper.createLayoutElementsForClassAndFieldNames(viewRowClass, fieldNames);
+			Check.assumeNotEmpty(elements, "elements is not empty"); // shall never happen
+
+			addElements(elements);
+			return this;
+		}
+
 		public boolean hasElements()
 		{
 			return !elementBuilders.isEmpty();

src/main/java/de/metas/ui/web/view/descriptor/annotation/ViewColumn.java

@@ -53,7 +53,7 @@
 	 * If empty, the column won't be displayed in any of {@link JSONViewDataType} profiles.
 	 */
 	ViewColumnLayout[] layouts() default {};
-	
+
 	ViewEditorRenderMode editor() default ViewEditorRenderMode.NEVER;
 
 	@Target({ ElementType.FIELD })
@@ -62,6 +62,12 @@
 	{
 		JSONViewDataType when();
 
+		/**
+		 * If <code>true</code> if the column shall be displayed by default.
+		 * If <code>false</code> the column will be displayed only on demand, when it was explicitly specified.
+		 */
+		boolean displayed() default true;
+
 		/** Display sequence number */
 		int seqNo();
 	}

src/main/java/de/metas/ui/web/view/descriptor/annotation/ViewColumnHelper.java

@@ -4,7 +4,6 @@
 import java.util.Comparator;
 import java.util.LinkedHashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.stream.Stream;
@@ -104,6 +103,17 @@ public static List<DocumentLayoutElementDescriptor.Builder> createLayoutElements
 				.collect(ImmutableList.toImmutableList());
 	}
 
+	public static List<DocumentLayoutElementDescriptor.Builder> createLayoutElementsForClassAndFieldNames(@NonNull final Class<?> dataType, @NonNull final String... fieldNames)
+	{
+		Check.assumeNotEmpty(fieldNames, "fieldNames is not empty");
+
+		final ClassViewDescriptor descriptor = getDescriptor(dataType);
+		return Stream.of(fieldNames)
+				.map(descriptor::getColumnByName)
+				.map(column -> createLayoutElement(column))
+				.collect(ImmutableList.toImmutableList());
+	}
+
 	private static ClassViewDescriptor createClassViewDescriptor(final Class<?> dataType)
 	{
 		@SuppressWarnings("unchecked")
@@ -133,6 +143,7 @@ private static ClassViewColumnDescriptor createClassViewColumnDescriptor(final F
 		final ImmutableMap<JSONViewDataType, ClassViewColumnLayoutDescriptor> layoutsByViewType = Stream.of(viewColumnAnn.layouts())
 				.map(layoutAnn -> ClassViewColumnLayoutDescriptor.builder()
 						.viewType(layoutAnn.when())
+						.displayed(layoutAnn.displayed())
 						.seqNo(layoutAnn.seqNo())
 						.build())
 				.collect(GuavaCollectors.toImmutableMapByKey(ClassViewColumnLayoutDescriptor::getViewType));
@@ -160,7 +171,7 @@ private static DocumentLayoutElementDescriptor.Builder createLayoutElement(final
 	public static <T extends IViewRow> ImmutableMap<String, Object> extractJsonMap(final T row)
 	{
 		final Class<? extends IViewRow> rowClass = row.getClass();
-		final Map<String, Object> result = new LinkedHashMap<>();
+		final LinkedHashMap<String, Object> result = new LinkedHashMap<>();
 		getDescriptor(rowClass)
 				.getColumns()
 				.forEach(column -> {
@@ -215,6 +226,14 @@ private ClassViewDescriptor(@Singular ImmutableList<ClassViewColumnDescriptor> c
 			this.widgetTypesByFieldName = columns.stream()
 					.collect(ImmutableMap.toImmutableMap(ClassViewColumnDescriptor::getFieldName, ClassViewColumnDescriptor::getWidgetType));
 		}
+
+		public ClassViewColumnDescriptor getColumnByName(@NonNull final String fieldName)
+		{
+			return columns.stream()
+					.filter(column -> fieldName.equals(column.getFieldName()))
+					.findFirst()
+					.orElseThrow(() -> new AdempiereException("No column found for " + fieldName + " in " + this));
+		}
 	}
 
 	@Value
@@ -238,7 +257,7 @@ private static final class ClassViewColumnDescriptor
 		public boolean isDisplayed(final JSONViewDataType viewType)
 		{
 			final ClassViewColumnLayoutDescriptor layout = layoutsByViewType.get(viewType);
-			return layout != null;
+			return layout != null && layout.isDisplayed();
 		}
 
 		public int getSeqNo(final JSONViewDataType viewType)
@@ -260,6 +279,7 @@ private static final class ClassViewColumnLayoutDescriptor
 	{
 		@NonNull
 		private JSONViewDataType viewType;
+		private final boolean displayed;
 		private final int seqNo;
 	}
 }