Add BackEndHierarchicalDataProvider and an abstract base class

diff --git a/server/src/main/java/com/vaadin/data/provider/AbstractBackEndHierarchicalDataProvider.java b/server/src/main/java/com/vaadin/data/provider/AbstractBackEndHierarchicalDataProvider.java
new file mode 100644 (file)
index 0000000..8cefc8a
--- /dev/null
+++ b/server/src/main/java/com/vaadin/data/provider/AbstractBackEndHierarchicalDataProvider.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.data.provider;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * Abstract base class for implementing
+ * {@link BackEndHierarchicalDataProvider}s.
+ *
+ * @author Vaadin Ltd
+ * @since 8.1
+ *
+ * @param <T>
+ *            data type
+ * @param <F>
+ *            filter type
+ */
+public abstract class AbstractBackEndHierarchicalDataProvider<T, F>
+        extends AbstractHierarchicalDataProvider<T, F>
+        implements BackEndHierarchicalDataProvider<T, F> {
+
+    private List<QuerySortOrder> sortOrders = new ArrayList<>();
+
+    private HierarchicalQuery<T, F> mixInSortOrders(
+            HierarchicalQuery<T, F> query) {
+        if (sortOrders.isEmpty()) {
+            return query;
+        }
+
+        Set<String> sortedPropertyNames = query.getSortOrders().stream()
+                .map(SortOrder::getSorted).collect(Collectors.toSet());
+
+        List<QuerySortOrder> combinedSortOrders = Stream
+                .concat(query.getSortOrders().stream(),
+                        sortOrders.stream()
+                                .filter(order -> !sortedPropertyNames
+                                        .contains(order.getSorted())))
+                .collect(Collectors.toList());
+
+        return new HierarchicalQuery<>(query.getOffset(), query.getLimit(),
+                combinedSortOrders, query.getInMemorySorting(),
+                query.getFilter().orElse(null), query.getParent());
+    }
+
+    @Override
+    public Stream<T> fetchChildren(HierarchicalQuery<T, F> query) {
+        return fetchChildrenFromBackEnd(mixInSortOrders(query));
+    }
+
+    @Override
+    public boolean isInMemory() {
+        return false;
+    }
+
+    @Override
+    public void setSortOrders(List<QuerySortOrder> sortOrders) {
+        this.sortOrders = Objects.requireNonNull(sortOrders,
+                "Sort orders cannot be null");
+        refreshAll();
+    }
+
+    /**
+     * Fetches data from the back end using the given query.
+     *
+     * @see HierarchicalQuery
+     *
+     * @param query
+     *            the query that defines sorting, filtering, paging and the
+     *            parent item to fetch children from
+     * @return a stream of items matching the query
+     */
+    protected abstract Stream<T> fetchChildrenFromBackEnd(
+            HierarchicalQuery<T, F> query);
+}

diff --git a/server/src/main/java/com/vaadin/data/provider/BackEndHierarchicalDataProvider.java b/server/src/main/java/com/vaadin/data/provider/BackEndHierarchicalDataProvider.java
new file mode 100644 (file)
index 0000000..82900bb
--- /dev/null
+++ b/server/src/main/java/com/vaadin/data/provider/BackEndHierarchicalDataProvider.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.data.provider;
+
+/**
+ * A data provider that lazy loads items from a back end containing hierarchical
+ * data.
+ *
+ * @author Vaadin Ltd
+ * @since 8.1
+ *
+ * @param <T>
+ *            data provider data type
+ * @param <F>
+ *            data provider filter type
+ */
+public interface BackEndHierarchicalDataProvider<T, F>
+        extends HierarchicalDataProvider<T, F>, BackEndDataProvider<T, F> {
+
+}

diff --git a/server/src/main/java/com/vaadin/ui/Tree.java b/server/src/main/java/com/vaadin/ui/Tree.java
index 7b8fae59ca404eed06fadc949312877a483bdba1..6ecbaac597f56fa6272fd487ffc7ada136919a7a 100644 (file)
--- a/server/src/main/java/com/vaadin/ui/Tree.java
+++ b/server/src/main/java/com/vaadin/ui/Tree.java
@@ -38,7 +38,6 @@ import com.vaadin.event.SerializableEventListener;
 import com.vaadin.event.selection.SelectionListener;
 import com.vaadin.server.ErrorMessage;
 import com.vaadin.server.Resource;
-import com.vaadin.server.SerializablePredicate;
 import com.vaadin.shared.Registration;
 import com.vaadin.shared.ui.ContentMode;
 import com.vaadin.shared.ui.grid.HeightMode;

diff --git a/uitest/src/main/java/com/vaadin/tests/components/treegrid/LazyHierarchicalDataProvider.java b/uitest/src/main/java/com/vaadin/tests/components/treegrid/LazyHierarchicalDataProvider.java
index 1fe7202d8a83ab80ced77601ec404e9eba3cb864..a468f34d2969a89d4c25617cdeb9518298b4b46e 100644 (file)
--- a/uitest/src/main/java/com/vaadin/tests/components/treegrid/LazyHierarchicalDataProvider.java
+++ b/uitest/src/main/java/com/vaadin/tests/components/treegrid/LazyHierarchicalDataProvider.java
@@ -5,12 +5,12 @@ import java.util.List;
 import java.util.Optional;
 import java.util.stream.Stream;
 
-import com.vaadin.data.provider.AbstractHierarchicalDataProvider;
+import com.vaadin.data.provider.AbstractBackEndHierarchicalDataProvider;
 import com.vaadin.data.provider.HierarchicalQuery;
 import com.vaadin.tests.data.bean.HierarchicalTestBean;
 
-public class LazyHierarchicalDataProvider
-        extends AbstractHierarchicalDataProvider<HierarchicalTestBean, Void> {
+public class LazyHierarchicalDataProvider extends
+        AbstractBackEndHierarchicalDataProvider<HierarchicalTestBean, Void> {
 
     private final int nodesPerLevel;
     private final int depth;
@@ -32,7 +32,16 @@ public class LazyHierarchicalDataProvider
     }
 
     @Override
-    public Stream<HierarchicalTestBean> fetchChildren(
+    public boolean hasChildren(HierarchicalTestBean item) {
+        return internalHasChildren(item);
+    }
+
+    private boolean internalHasChildren(HierarchicalTestBean node) {
+        return node.getDepth() < depth;
+    }
+
+    @Override
+    protected Stream<HierarchicalTestBean> fetchChildrenFromBackEnd(
             HierarchicalQuery<HierarchicalTestBean, Void> query) {
         final int depth = query.getParentOptional().isPresent()
                 ? query.getParent().getDepth() + 1 : 0;
@@ -46,18 +55,4 @@ public class LazyHierarchicalDataProvider
         }
         return list.stream();
     }
-
-    @Override
-    public boolean hasChildren(HierarchicalTestBean item) {
-        return internalHasChildren(item);
-    }
-
-    private boolean internalHasChildren(HierarchicalTestBean node) {
-        return node.getDepth() < depth;
-    }
-
-    @Override
-    public boolean isInMemory() {
-        return false;
-    }
 }