Add ItemCollapseAllowedProvider interface

4 files changed, 52 insertions, 7 deletions

diff --git a/server/src/main/java/com/vaadin/data/provider/HierarchicalDataCommunicator.java b/server/src/main/java/com/vaadin/data/provider/HierarchicalDataCommunicator.java
index df2a11c200..ce6f7db13e 100644
--- a/server/src/main/java/com/vaadin/data/provider/HierarchicalDataCommunicator.java
+++ b/server/src/main/java/com/vaadin/data/provider/HierarchicalDataCommunicator.java
@@ -31,10 +31,10 @@ import com.vaadin.data.TreeData;
 import com.vaadin.data.provider.HierarchyMapper.TreeLevelQuery;
 import com.vaadin.data.provider.HierarchyMapper.TreeNode;
 import com.vaadin.server.SerializableConsumer;
-import com.vaadin.server.SerializablePredicate;
 import com.vaadin.shared.Range;
 import com.vaadin.shared.data.HierarchicalDataCommunicatorConstants;
 import com.vaadin.shared.extension.datacommunicator.HierarchicalDataCommunicatorState;
+import com.vaadin.ui.ItemCollapseAllowedProvider;
 
 import elemental.json.Json;
 import elemental.json.JsonArray;
@@ -66,7 +66,7 @@ public class HierarchicalDataCommunicator<T> extends DataCommunicator<T> {
     /**
      * Collapse allowed provider used to allow/disallow collapsing nodes.
      */
-    private SerializablePredicate<T> itemCollapseAllowedProvider = t -> true;
+    private ItemCollapseAllowedProvider<T> itemCollapseAllowedProvider = t -> true;
 
     /**
      * The captured client side cache size.
@@ -521,7 +521,7 @@ public class HierarchicalDataCommunicator<T> extends DataCommunicator<T> {
      *            the item collapse allowed provider, not {@code null}
      */
     public void setItemCollapseAllowedProvider(
-            SerializablePredicate<T> provider) {
+            ItemCollapseAllowedProvider<T> provider) {
         Objects.requireNonNull(provider, "Provider can't be null");
         itemCollapseAllowedProvider = provider;
 
diff --git a/server/src/main/java/com/vaadin/ui/ItemCollapseAllowedProvider.java b/server/src/main/java/com/vaadin/ui/ItemCollapseAllowedProvider.java
new file mode 100644
index 0000000000..2ec0ad20e3
--- /dev/null
+++ b/server/src/main/java/com/vaadin/ui/ItemCollapseAllowedProvider.java
@@ -0,0 +1,46 @@
+/*
+ * 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.ui;
+
+import com.vaadin.server.SerializablePredicate;
+
+/**
+ * A callback interface for resolving whether client-side collapsing should be
+ * allowed for an item in a listing component that displays hierarchical data,
+ * such as {@link TreeGrid}.
+ *
+ * @author Vaadin Ltd
+ * @since 8.1
+ *
+ * @see TreeGrid#setItemCollapseAllowedProvider(ItemCollapseAllowedProvider)
+ *
+ * @param <T>
+ *            item data type
+ */
+@FunctionalInterface
+public interface ItemCollapseAllowedProvider<T> extends SerializablePredicate<T> {
+
+    /**
+     * Returns whether collapsing is allowed for the given item.
+     *
+     * @param item
+     *            the item to test
+     * @return {@code true} if collapse is allowed for the given item,
+     *         {@code false} otherwise
+     */
+    @Override
+    boolean test(T item);
+}
diff --git a/server/src/main/java/com/vaadin/ui/Tree.java b/server/src/main/java/com/vaadin/ui/Tree.java
index 9f30c010db..7b8fae59ca 100644
--- a/server/src/main/java/com/vaadin/ui/Tree.java
+++ b/server/src/main/java/com/vaadin/ui/Tree.java
@@ -470,7 +470,7 @@ public class Tree<T> extends Composite
      *            the item collapse allowed provider, not {@code null}
      */
     public void setItemCollapseAllowedProvider(
-            SerializablePredicate<T> provider) {
+            ItemCollapseAllowedProvider<T> provider) {
         treeGrid.setItemCollapseAllowedProvider(provider);
     }
 
diff --git a/server/src/main/java/com/vaadin/ui/TreeGrid.java b/server/src/main/java/com/vaadin/ui/TreeGrid.java
index f24e5ca9ec..54e8e10a6c 100644
--- a/server/src/main/java/com/vaadin/ui/TreeGrid.java
+++ b/server/src/main/java/com/vaadin/ui/TreeGrid.java
@@ -43,7 +43,6 @@ import com.vaadin.event.CollapseEvent;
 import com.vaadin.event.CollapseEvent.CollapseListener;
 import com.vaadin.event.ExpandEvent;
 import com.vaadin.event.ExpandEvent.ExpandListener;
-import com.vaadin.server.SerializablePredicate;
 import com.vaadin.shared.Registration;
 import com.vaadin.shared.ui.treegrid.FocusParentRpc;
 import com.vaadin.shared.ui.treegrid.FocusRpc;
@@ -324,10 +323,10 @@ public class TreeGrid<T> extends Grid<T>
      * @param provider
      *            the item collapse allowed provider, not {@code null}
      *
-     * @see HierarchicalDataCommunicator#setItemCollapseAllowedProvider(SerializablePredicate)
+     * @see HierarchicalDataCommunicator#setItemCollapseAllowedProvider(ItemCollapseAllowedProvider)
      */
     public void setItemCollapseAllowedProvider(
-            SerializablePredicate<T> provider) {
+            ItemCollapseAllowedProvider<T> provider) {
         getDataCommunicator().setItemCollapseAllowedProvider(provider);
     }