Combine and rename setFilter and applyFilter (#7963)

setFilter is an unsuitable name since it looks like a setter even though
it isn't one. It's therefore renamed to withFilter.

The difference between setFilter and applyFilter is very confusing. The
original reason for the distinction was that they had incompatible
return types (Void vs F), but this is resolved by changing the
non-appendable version to use ? instead of Void.

One side effect of this change is that setFilter cannot be used on an
appendable filter provider to create a wrapped data provider without
further filtering support. This theorethical case is still supported by
using convertFilter with a Void -> F converter.

6 files changed, 16 insertions, 27 deletions

diff --git a/server/src/main/java/com/vaadin/server/data/AppendableFilterDataProvider.java b/server/src/main/java/com/vaadin/server/data/AppendableFilterDataProvider.java
index 845488d4f1..c6e20acbe4 100644
--- a/server/src/main/java/com/vaadin/server/data/AppendableFilterDataProvider.java
+++ b/server/src/main/java/com/vaadin/server/data/AppendableFilterDataProvider.java
@@ -37,7 +37,8 @@ public interface AppendableFilterDataProvider<T, F> extends DataProvider<T, F> {
      *            the applied filter; not {@code null}
      * @return new data provider with the filter applied
      */
-    public default AppendableFilterDataProvider<T, F> applyFilter(F filter) {
+    @Override
+    public default AppendableFilterDataProvider<T, F> withFilter(F filter) {
         Objects.requireNonNull(filter, "The applied filter can't be null");
         return DataProviderWrapper.chain(this, filter);
     }
diff --git a/server/src/main/java/com/vaadin/server/data/DataProvider.java b/server/src/main/java/com/vaadin/server/data/DataProvider.java
index 5c60ca0951..1a0360318b 100644
--- a/server/src/main/java/com/vaadin/server/data/DataProvider.java
+++ b/server/src/main/java/com/vaadin/server/data/DataProvider.java
@@ -111,7 +111,7 @@ public interface DataProvider<T, F> extends Serializable {
      *            the default filter
      * @return wrapped data provider with provided filter
      */
-    public default DataProvider<T, Void> setFilter(F filter) {
+    public default DataProvider<T, ?> withFilter(F filter) {
         Objects.requireNonNull(filter, "Filter can't be null");
         return DataProviderWrapper.filter(this, filter);
     }
diff --git a/server/src/main/java/com/vaadin/server/data/DataProviderWrapper.java b/server/src/main/java/com/vaadin/server/data/DataProviderWrapper.java
index a04d4a07bd..ba08ac4ef6 100644
--- a/server/src/main/java/com/vaadin/server/data/DataProviderWrapper.java
+++ b/server/src/main/java/com/vaadin/server/data/DataProviderWrapper.java
@@ -125,7 +125,7 @@ public abstract class DataProviderWrapper<T, F, M>
      * This {@code DataProvider} will deliberately ignore any possible filters
      * from the Query.
      *
-     * @see DataProvider#setFilter(Object)
+     * @see DataProvider#withFilter(Object)
      *
      * @param dataProvider
      *            the underlying data provider
@@ -145,6 +145,8 @@ public abstract class DataProviderWrapper<T, F, M>
 
             @Override
             protected F getFilter(Query<T, Void> query) {
+                assert !query.getFilter()
+                        .isPresent() : "A filter is provided to a data provider that should be unfilterable";
                 return filter;
             }
         };
diff --git a/server/src/test/java/com/vaadin/server/data/provider/DataProviderTestBase.java b/server/src/test/java/com/vaadin/server/data/provider/DataProviderTestBase.java
index d930162016..b6a6bfa11f 100644
--- a/server/src/test/java/com/vaadin/server/data/provider/DataProviderTestBase.java
+++ b/server/src/test/java/com/vaadin/server/data/provider/DataProviderTestBase.java
@@ -66,7 +66,7 @@ public abstract class DataProviderTestBase<D extends DataProvider<StrBean, Seria
     private Query<StrBean, SerializablePredicate<StrBean>> createQuery(
             List<SortOrder<String>> sortOrder, Comparator<StrBean> comp,
             SerializablePredicate<StrBean> filter) {
-        return new Query<StrBean, SerializablePredicate<StrBean>>(0,
+        return new Query<>(0,
                 Integer.MAX_VALUE, sortOrder, comp, filter);
     }
 
@@ -296,18 +296,4 @@ public abstract class DataProviderTestBase<D extends DataProvider<StrBean, Seria
         Assert.assertEquals("Unexpected number of matches for 'Foo'", 36,
                 dataProvider.size(new Query<>(fooFilter)));
     }
-
-    @Test
-    public void filteringListDataProvider_defaultFilter() {
-        // Intentionally lost filter type. Not actually filterable anymore.
-        DataProvider<StrBean, ?> filtered = dataProvider.setFilter(gt5Filter);
-
-        Assert.assertEquals("Filter not applied, unexpected item count",
-                dataProvider.size(new Query<>(gt5Filter)),
-                filtered.size(new Query<>()));
-
-        Assert.assertEquals("Further filtering succeeded",
-                filtered.size(new Query<>()),
-                filtered.size((Query) new Query<>(fooFilter)));
-    }
 }
diff --git a/server/src/test/java/com/vaadin/server/data/provider/ListDataProviderTest.java b/server/src/test/java/com/vaadin/server/data/provider/ListDataProviderTest.java
index a018148dfa..1141675ac1 100644
--- a/server/src/test/java/com/vaadin/server/data/provider/ListDataProviderTest.java
+++ b/server/src/test/java/com/vaadin/server/data/provider/ListDataProviderTest.java
@@ -24,11 +24,11 @@ public class ListDataProviderTest
     public void filteringListDataProvider_appliedFilters() {
         Assert.assertEquals("Filtering result differ",
                 data.stream().filter(fooFilter).count(),
-                dataProvider.applyFilter(fooFilter).size(new Query<>()));
+                dataProvider.withFilter(fooFilter).size(new Query<>()));
 
         Assert.assertEquals("Chained filtering result differ",
                 data.stream().filter(fooFilter.and(gt5Filter)).count(),
-                dataProvider.applyFilter(fooFilter)
+                dataProvider.withFilter(fooFilter)
                         .size(new Query<>(gt5Filter)));
     }
 
@@ -36,7 +36,7 @@ public class ListDataProviderTest
     public void filteringListDataProvider_chainedFilters() {
         Assert.assertEquals("Chained filtering result differ",
                 data.stream().filter(fooFilter.and(gt5Filter)).count(),
-                dataProvider.applyFilter(fooFilter).applyFilter(gt5Filter)
+                dataProvider.withFilter(fooFilter).withFilter(gt5Filter)
                         .size(new Query<>()));
     }
 
@@ -55,26 +55,26 @@ public class ListDataProviderTest
 
         Assert.assertEquals("Chained filtering result differ",
                 data.stream().filter(fooFilter.or(gt5Filter)).count(),
-                orFilteredDataProvider.applyFilter(fooFilter)
-                        .applyFilter(gt5Filter).size(new Query<>()));
+                orFilteredDataProvider.withFilter(fooFilter)
+                        .withFilter(gt5Filter).size(new Query<>()));
     }
 
     @Test
     public void filteringListDataProvider_appliedFilterAndConverter() {
         Assert.assertEquals("Filtering result differ with 'Foo'",
                 data.stream().filter(gt5Filter.and(fooFilter)).count(),
-                dataProvider.applyFilter(gt5Filter).convertFilter(
+                dataProvider.withFilter(gt5Filter).convertFilter(
                         text -> strBean -> strBean.getValue().equals(text))
                         .size(new Query<>("Foo")));
 
         Assert.assertEquals("Filtering result differ with 'Xyz'", data.stream()
                 .filter(gt5Filter.and(s -> s.getValue().equals("Xyz"))).count(),
-                dataProvider.applyFilter(gt5Filter).convertFilter(
+                dataProvider.withFilter(gt5Filter).convertFilter(
                         text -> strBean -> strBean.getValue().equals(text))
                         .size(new Query<>("Xyz")));
 
         Assert.assertEquals("No results should've been found", 0,
-                dataProvider.applyFilter(gt5Filter).convertFilter(
+                dataProvider.withFilter(gt5Filter).convertFilter(
                         text -> strBean -> strBean.getValue().equals(text))
                         .size(new Query<>("Zyx")));
     }
diff --git a/server/src/test/java/com/vaadin/tests/server/component/combobox/ComboBoxFilteringTest.java b/server/src/test/java/com/vaadin/tests/server/component/combobox/ComboBoxFilteringTest.java
index de03684307..9719cd43b8 100644
--- a/server/src/test/java/com/vaadin/tests/server/component/combobox/ComboBoxFilteringTest.java
+++ b/server/src/test/java/com/vaadin/tests/server/component/combobox/ComboBoxFilteringTest.java
@@ -143,7 +143,7 @@ public class ComboBoxFilteringTest {
         ListDataProvider<Person> ldp = DataProvider.create(getPersonArray());
         // Same as above, but only showing a subset of the persons
         comboBox.setDataProvider(ldp
-                .applyFilter(person -> person.getFirstName().contains("nr"))
+                .withFilter(person -> person.getFirstName().contains("nr"))
                 .convertFilter(
                         text -> person -> person.getLastName().contains(text)));